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PubMed2005

An Uncaria tomentosa (cat's claw) extract protects mice against ozone-induced lung inflammation.

Ozone (O(3)) inhalation has been associated with respiratory tract inflammation and lung functional alterations. To characterize the O(3)-induced lung inflammation in mice, the effective dose and exposure time were determined. Total protein levels of bronchoalveolar lavage fluid (BALF), cytological smears, and lung histopathology and morphometry were used to assess and measure the degree of pulmonary inflammation in the mouse model. Ozone inhalation caused acute pneumonitis that was characterized by a high number of infiltrating neutrophils (PMNs) immediately after exposure and increased levels of protein in BALF in mice killed 8h after O(3) exposure. The anti-inflammatory properties of Uncaria tomentosa (UT) have been documented previously. To evaluate the anti-inflammatory effects of UT, male mice were given an UT extract for 8 days, exposed to O(3), and killed 0 or 8 h after O(3) exposure. When compared to untreated controls, UT-treated mice had significantly (p < 0.05) lower levels of protein in BALF, lower degree of epithelial necrosis, higher number of intact epithelial cell nuclei in bronchial wall, and decreased number of PMNs in the bronchiolar lumen. Therefore, UT extract appeared to prevent O(3)-induced respiratory inflammation in male mice.

Administration, Inhalation↗

PubMed2006

Effect of total phenolics from Laggera alata on acute and chronic inflammation models.

The anti-inflammatory effect of total phenolics from Laggera alata (TPLA) was evaluated with various in vivo models of both acute and chronic inflammations. In the acute inflammation tests, TPLA inhibited significantly xylene-induced mouse ear oedema, carrageenan-induced rat paw oedema and acetic acid-induced mouse vascular permeability. In the carrageenan-induced rat pleurisy model, TPLA significantly suppressed inflammatory exudate and leukocyte migration, reduced the serum levels of lysozyme (LZM) and malondialdehyde (MDA), increased the serum levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), and also decreased the contents of total protein, nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in the pleural exudates. In the chronic inflammation experiment, TPLA inhibited significantly cotton pellet-induced rat granuloma. These results indicated that TPLA possesses potent anti-inflammatory activity on acute and chronic inflammation models. Its anti-inflammatory mechanisms are probably associated with the inhibition of prostaglandin formation, the influence on the antioxidant systems, and the suppression of LZM release. Furthermore, the total phenolic content of Laggera alata and its main component type was quantified, and its principle components were isolated and authenticated. Acute toxicity studies revealed that TPLA up to an oral dose of 8.5 g/kg body weight was almost nontoxic in mice.

Acute Disease↗

PubMed2005

Neonatal chronic hind paw inflammation alters sensitization to intradermal capsaicin in adult rats: a behavioral and immunocytochemical study.

UNLABELLED: The present studies were conducted to examine functional consequences of postnatal chronic inflammation, initiated during a critical developmental period, on capsaicin-evoked hyperalgesia and neuronal activation in adulthood. Rats received a unilateral intraplantar injection of complete Freund's adjuvant (CFA; diluted 2:1 in saline) on postnatal day 0 (P0-CFA) or 14 (P14-CFA). Separate groups received an equivalent volume of saline on P0 (P0-vehicle) or were untreated (P0-untreated). Increases in capsaicin-evoked thermal and mechanical hyperalgesia and allodynia were observed in adult P0-CFA-treated rats relative to control conditions. By contrast, this enhancement was absent in P14-CFA-treated rats, suggesting that the developmental period differentially affects the appearance of the observed behavioral phenotype. Capsaicin-evoked nocifensive behavior was also lower in P14-CFA-treated rats relative to P0-CFA-treated rats. Capsaicin-evoked Fos protein expression was increased in the superficial and neck regions of the dorsal horn of adult P0-CFA-treated rats relative to P0-vehicle-treated rats. These changes were absent in the nucleus proprius and ventral horn. The present data are consistent with the hypothesis that neonatal chronic inflammation permanently alters sensitivity to pain in adulthood, consistent with modulation of primary afferent activation and central sensitization in response to a subsequent nociceptive challenge in adulthood. PERSPECTIVE: Chronic inflammation during development can induce profound alterations in sensory processing later in life. Here we show that long-term inflammation initiated at critical developmental stages sensitizes both behavioral and neuronal responses to nociceptor stimulation in adulthood. An ongoing sensitization of the spinal cord is induced by the postnatal inflammatory insult.

Afferent Pathways↗

PubMed2005

Adenosine A2A receptor activation reduces inflammation and preserves pulmonary function in an in vivo model of lung transplantation.

BACKGROUND: Reperfusion injury continues to significantly affect patients undergoing lung transplantation. Isolated lung models have demonstrated that adenosine A 2A receptor activation preserves function while decreasing inflammation. We hypothesized that adenosine A 2A receptor activation by ATL-146e during the initial reperfusion period preserves pulmonary function and attenuates inflammation in a porcine model of lung transplantation. METHODS: Mature pig lungs preserved with Viaspan (Barr Laboratories, Pomona, NY) underwent 6 hours of cold ischemia before transplantation and 4 hours of reperfusion. Animals were treated with (ATL group, n = 7) and without (IR group, n = 7) ATL-146e (0.05 microg kg -1 . min -1 ATL-146e administered intravenously for 3 hours). With occlusion of the opposite pulmonary artery, the animal was maintained for the final 30 minutes on the allograft alone. Recipient lung physiology was monitored before tissue evaluation of pulmonary edema (wet-to-dry weight ratio), myeloperoxidase assay, and tissue tumor necrosis factor alpha by means of enzyme-linked immunosorbent assay. RESULTS: When the ATL group was compared with the IR group, the ATL group had better partial pressure of carbon dioxide (43.8 +/- 4.1 vs 68.9 +/- 6.3 mm Hg, P < .01) and partial pressure of oxygen (272.3 +/- 132.7 vs 100.1 +/- 21.4 mm Hg, P < .01). ATL-146e-treated animals exhibited lower pulmonary artery pressures (33.6 +/- 2.1 vs 47.9 +/- 3.5 mm Hg, P < .01) and mean airway pressures (16.25 +/- 0.08 vs 16.64 +/- 0.15 mm Hg, P = .04). ATL-146e-treated lungs had lower wet-to-dry ratios (5.9 +/- 0.39 vs 7.3 +/- 0.38, P < .02), lower myeloperoxidase levels (2.9 x 10 -5 +/- 1.2 x 10 -5 vs 1.3 x 10 -4 +/- 4.0 x 10 -5 DeltaOD mg -1 . min -1 , P = .03), and a trend toward decreased lung tumor necrosis factor alpha levels (57 +/- 12 vs 96 +/- 15 pg/mL, P = .06). The ATL group demonstrated significantly less inflammation on histology. CONCLUSION: Adenosine A 2A activation during early reperfusion attenuated lung inflammation and preserved pulmonary function in this model of lung transplantation. ATL-146e and similar compounds could play a significant role in improving outcomes of pulmonary transplantation.

Adenosine A2 Receptor Agonists↗

PubMed2004

Inhibition of NF-kappaB mediated inflammation by siRNA expressed by recombinant adeno-associated virus.

NF-kappaB mediated inflammation is a key process to many diseases. RNA interference (RNAi) is the specific suppression of genes by short double-stranded RNA. It was the aim of the present study to modify NF-kappaBdependent inflammation by small interfering RNA (siRNA) expressed by recombinant adeno-associated virus (rAAV). To study the kinetics of rAAV mediated expression of siRNA, the expression of the luciferase gene was targeted and resulted in a significant decrease of luciferase activity as compared to a control vector in the human 293 cell line. The effect was dose dependent and was detectable 24 h after infection. rAAV coding for siRNA against the p65 subunit of NF-kappaBsignificantly reduced the p65 protein. In a cellular model of TNF-alpha induced inflammation, expression of siRNA against p65 significantly suppressed the secretion of IL-8 from BEAS-2B cells. In conclusion, rAAV vectors coding for siRNA are an useful tool for efficient gene silencing in mammalian cells and can be used to modify NF-kappaB mediated inflammation.

Cell Line↗

PubMed2005

Inflammation may be a bridge connecting hypertension and atherosclerosis.

Pathogenesis of the atherosclerotic process is deemed as multi-factorial, and characterized by chronic inflammatory response. Although hypertension is known to be one of the most important risk factors for atherosclerosis in causasians, its relative contribution to early atherosclerosis are still unknown. Increased evidence has indicated that hypertension, through the vasoactive peptides, such as angiotensin and endothelin-1, promotes and accelerates the atherosclerotic process via inflammatory mechanisms. In animal and human studies pro-inflammatory properties of angiotensin II has been demonstrated in large conduit and small arteries, in the kidney as well as in the heart. Activation of oxidative stress by angiotensin II is a key component of this process. Angiotensin II stimulates nicotinamide adenine dinucleotide phosphate/nicotinamide adenine dinucleotide oxidase in endothelium, smooth muscle cells, and the adventitia of blood vessel to generate reactive oxygen species, leading to endothelial dysfunction, growth, and inflammation, upregulation of endothelin-1, adhesion molecules, nuclear factor-kappa B, and other inflammatory mediators, as well as increased breakdown of nitric oxide and uncoupling of nitric oxide synthase, contribute to the progression of vascular disease and atherogenesis. In addition, recent advances concerning role of endothelin-1 as another important mediator of chronic inflammation in the vascular wall has been documented, and relationship between endothelin-1 and angiotensin II on vascular inflammation demonstrated. Inflammatory mechanisms, therefore, are important participants in the pathophysiology of hypertension-related cardiovascular disease, including atherosclerosis. In experimental models as well as human studies of atherosclerosis, angiotensin converting enzyme inhibitors or angiotensin II receptor blockers have demonstrated the ability to prevent or reverse the progression of atherosclerosis, which was in part associated with decreased expression of inflammatory mediators and improve endothelial functions. Based on those increasing evidence, we hypothesize that inflammation may be a bridge connecting hypertension and atherosclerosis.

Arteriosclerosis↗

PubMed2005

Is slow coronary flow associated with inflammation?

Cardiologists are familiar with the phenomenon of slow progression of angiographic contrast in the coronary arteries in the absence of stenosis in the epicardial vessels in some patients presenting with chest pain. This phenomenon is called as coronary slow flow phenomenon, and firstly described in 1972, while it remains scantily studied. The pathophysiological mechanisms of coronary slow flow phenomenon remain uncertain. Several hypotheses however, have been suggested for slow coronary flow phenomenon, including a form of early phase of atherosclerosis, small vessel dysfunction, Hagen-Poiseuille's equation model, imbalance between vasoconstrictor and vasodilatory factors, and platelet function disorder. More recently, there has been mounting evidence that inflammation plays an important role in the initiation, development as well as evolution of atherosclerosis, suggesting that atherosclerosis is an inflammation disease. New evidence has also indicated that inflammation may be involved in the development of slow coronary flow phenomenon. Coronary slow flow phenomenon is an important clinical entity because it may be the cause of angina at rest or during exercise, acute myocardial infarction, and hypertension. Despite the good prognosis of this kind of patients, the chronic, frequent nature of the persistent uncomfortable chest can significantly impair the quality of life. Whether this is really a new kind of coronary disease involving in inflammation, however, is still unknown and deserves further investigation.

Angiography↗

PubMed2006

Inflammation in variant angina: is there any evidence?

Variant angina, defined as spontaneous angina pectoris associated with transient ST-segment elevation, has proved to be caused usually by episodic coronary spasm since Prinzmetal and his associates described a form of angina quite different from classic Heberden angina pectoris in 1959. Currently, coronary artery spasm is defined as reversible coronary stenosis, which limits coronary blood flow under resting conditions, and it plays an important role in ischemic heart disease, particularly in variant angina. Data available in respect of coronary vasospasm showed that it is closely related to atherosclerotic coronary artery disease, since intravascular ultrasound studies reveal atherosclerotic plaques in almost any spastic segment. Risk factors for coronary artery disease and coronary vasospasm, however, differ profoundly. Cigarette smoking is the only established risk factor. Although several candidates and predisposing factors, such as serotonin, histamine, thromboxane, and endothelin, have been described, the mediators and the pathogenesis of the disease remain unknown. There are abundant studies that inflammation plays an important role in the initiation, development as well as evolution of atherosclerosis, suggesting that atherosclerosis is an inflammation disease. The evidence regarding the role of inflammatory pathways in different clinical entities of coronary artery disease has significantly been accumulated. And also, primary studies have showed that inflammation may be a contributor for variant angina or vasospastic coronary disease is at least partially driven by inflammation. Although much more research is obviously needed, primary evidence provide us with some direction for that research.

Angina Pectoris, Variant↗

PubMed2005

Endothelial activation and inflammation in prepubertal obese Turkish children.

To investigate the degree of endothelial activation and inflammation in prepubertal obese children and to determine the relationship between the markers of endothelial activation, inflammation, and cardiovascular risk factors. In 30 obese and 28 healthy prepubertal children, soluble intercellular adhesion molecule-1 and endothelial leukocyte adhesion molecule-1 (sE-selectin) as markers of endothelial activation and soluble vascular cell adhesion molecule-1 (sVCAM-1) and C-reactive protein (CRP) as markers of endothelial inflammation in addition to cardiovascular risk factors including blood lipids, glucose, insulin, hemoglobin A1c, and systolic and diastolic blood pressure were investigated and compared. The tests were repeated after an oral glucose tolerance test in the obese group. Fasting CRP levels were found to be significantly higher in obese children. Vascular cell adhesion molecule-1 levels were found to be significantly increased in obese children after oral glucose tolerance test. Fasting CRP was positively correlated with body mass index (BMI) and low-density lipoprotein, whereas sE-selectin was positively correlated with total cholesterol. In the obese group, postload levels of soluble sE-selectin was positively correlated with low-density lipoprotein; sVCAM-1 was positively correlated with insulin and homeostasis model assessment values. Postload soluble intercellular adhesion molecule-1, sVCAM-1, and soluble sE-selectin levels were also positively correlated with each other. In the fasting state, BMI was the significant independent risk factor for CRP, and total cholesterol was the significant risk factor for soluble sE-selectin. Insulin resistance was the significant independent risk factor for postload sVCAM-1, and postload low-density lipoprotein stood as the significant independent risk factor for postload soluble sE-selectin. Endothelial inflammation is present in obese prepubertal children and is mainly associated with insulin resistance and lipid levels as well as BMI.

Body Mass Index↗

PubMed2003

Control of Mycobacterium bovis BCG infection with increased inflammation in TLR4-deficient mice.

Live mycobacteria have been reported to signal through several pattern recognition receptors (PRR), among them toll-like receptor 4 (TLR4) and TLR2 in vitro. Here, we investigated the role of TLR4 in host resistance to Mycobacterium bovis (BCG) infection in vivo. In vitro, macrophages of TLR4 mutant C3H/HeJ mice infected with BCG expressed lower levels of TNF than controls, and TNF release was further decreased, although not completely absent, in the absence of TLR2. In vivo, TLR4 mutant C3H/HeJ and control C3H/HeOUJ mice were infected with BCG (2 x 10(6) CFU i.v.). Both TLR4 mutant and wild-type mice were able to control the infection and survived 8 months post-BCG infection. Macrophage activation with abundant acid-fast bacilli and expression of inducible nitric oxide synthase (iNOS) and MHC class II antigens was seen in both groups of mice. However, TLR4 mutant mice experienced an arrest of body weight gain and showed signs of increased inflammation, with persistent splenomegaly, increase in granuloma number and augmented neutrophil infiltration. Infection of TLR4-deficient mice with higher doses of BCG (1 and 3 x 10(7) CFU, i.v.) increased the inflammation in spleen and liver, associated with a transient, higher bacterial load in the liver. In summary, TLR4 mutant mice show normal macrophage recruitment and activation, granuloma formation and control of the BCG infection, but this is associated with persistent inflammation. Therefore, TLR4 signaling is not essential for early control of BCG infection, but it may have a critical function in fine tuning of inflammation during chronic mycobacterial infection.

Animals↗

PubMed2026

Peripheral inflammation and executive function among community samples across the lifespan: A systematic review and meta-analysis.

Higher levels of peripheral inflammatory markers are proposed to disrupt cognitive processes; however, the extent to which this relationship applies to executive functions, specifically, has yet to be systematically evaluated. The current meta-analysis synthesizes all available literature measuring the association between peripheral inflammation and executive functions among community individuals across the lifespan. This systematic review searched Web of Science, PubMed, and PsycINFO for published and unpublished studies, in the English language, that assessed the association between markers of peripheral inflammation and self-report and behavioral measures of executive function. In addition to methodological and demographic information, correlation/beta coefficients were extracted from included studies to quantify the association between inflammation and executive functions. This review included 58 studies, 41 of which were included in the random-effects meta-analysis (N = 255,539). Among community individuals, higher levels of CRP and IL-6 were associated with poorer executive functioning. These results did not differ when models accounted for potential confounding variables. Meta-regressions revealed that the relationship between inflammatory biomarkers and executive function did not differ as a function of age, adiposity, or percentage of the sample who identified as female. Results of the present review indicate that higher levels of specific inflammatory markers are associated with lower performance on executive function measures; however, we observed significant heterogeneity in the study design and measurement of both inflammation and executive functioning, suggesting important considerations for future research.

Humans↗

PubMed2004

Persistent hindpaw inflammation produces coeruleospinal antinociception in the non-inflamed forepaw of rats.

In a rat model of unilateral hindpaw inflammation, it is unclear whether the coeruleospinal modulation system is active at spinal segments distant from the inflamed plantar region, such as the cervical segments. To clarify this query, in the present study we measured paw withdrawal latency (PWL) to thermal stimuli on four paws (both forepaws and both hindpaws) following induction of inflammation and compared PWLs between rats with bilateral lesions of the locus coeruleus/subcoeruleus (LC/SC) and rats with sham operation. Unilateral hindpaw inflammation was produced by a subcutaneous injection of carrageenan (2 mg in 0.15 ml saline). Prior to carrageenan injection, in all four paws, PWLs did not differ between the LC/SC-lesioned and the sham-operated rats. Four hours after carrageenan injection, PWLs in the inflamed left hindpaw decreased significantly in both the LC/SC-lesioned and the sham-operated rats. The decreased PWLs of the LC/SC-lesioned group were significantly shorter than those of the sham-operated group. These phenomena which were observed in the inflamed left hindpaw were also observed in the non-inflamed left forepaws. In the right forepaws and the right hindpaws, no significant change in PWL was observed between before and 4 h after injection in both the sham-operated and the LC/SC-lesioned rats. These results suggest that unilateral hindpaw inflammation activates the coeruleospinal modulation system and that this modulation system is active not only at the lumbar segments but also at the cervical level where spinal segments are distant from the inflamed plantar region.

Animals↗

PubMed2004

Capsaicin-evoked substance P release in rat dorsal horn increases after peripheral inflammation: a microdialysis study.

Numerous in vitro studies suggest that inflammation is associated with enhanced release of substance P (SP) in the dorsal horn. To test the hypothesis that inflammation increases the evoked concentration of SP in the intact animal, we used in vivo microdialysis with a highly sensitive radioimmunoassay to monitor SP-like immunoreactivity (SP-LI) in the dorsal horn. Seven days after the induction of persistent unilateral inflammation with hindpaw injection of complete Freund's adjuvant, perfusion of the microdialysis probe with 10 microM capsaicin (a concentration which failed to induce SP-LI release in rats without inflammation) induced a significant increase of microdialysate SP-LI. Inclusion of an NMDA antagonist in the perfusion fluid completely blocked this capsaicin-evoked SP release. Administration of a five-fold higher dose of capsaicin did not further increase SP release. These results in a rat model of chronic arthritis suggest that persistent inflammatory signaling facilitates capsaicin-evoked SP release in the dorsal horn in vivo.

Animals↗

PubMed2006

Inflammation of craniofacial muscle induces widespread mechanical allodynia.

The modulation of behavioral responses evoked by local and distant nociceptive stimuli following a discrete somatic injection of complete Freund's adjuvant (CFA) was examined in rats. Inflammation of one craniofacial muscle evoked mechanical allodynia not only in the region of inflammation but also secondary mechanical allodynia in the contralateral head, ipsilateral hindpaw, and contralateral hindpaw. In contrast to this, CFA-induced inflammation of either the hindpaw or gastrocnemius muscle evoked mechanical allodynia restricted to the hindlimb region. The widespread modulation of nocifensive behavior evoked by inflammation of deep craniofacial tissue found in this study resembles the widespread deep tissue pain reported in fibromyalgia, whiplash injury and some temporomandibular disorders and thus may provide insight into the mechanisms of these musculoskeletal pathologies.

Analysis of Variance↗

PubMed2006

Effects of bee venom peptidergic components on rat pain-related behaviors and inflammation.

To identify the active components of honeybee venom in production of inflammation and pain-related behaviors, five major peptidergic subfractions were separated, purified and identified from the whole honeybee venom. Among them, four active peptidergic components were characterized as apamin, mast-cell degranulating peptide (MCDP), phospholipase A(2) (PLA(2))-related peptide and melittin, respectively. All five subfractions were effective in production of local inflammatory responses (paw edema) in rats although the efficacies were different. Among the five identified subfractions, only MCDP, PLA(2)-related peptide and melittin were able to produce ongoing pain-related behaviors shown as paw flinches, while only apamin and melittin were potent to produce both thermal and mechanical hypersensitivity. As shown in our previous report, melittin was the most potent polypeptide in production of local inflammation as well as ongoing pain and hypersensitivity. To further explore the peripheral mechanisms underlying melittin-induced nociception and hypersensitivity, a single dose of capsazepine, a blocker of thermal nociceptor transient receptor potential vanilloid receptor 1, was treated s.c. prior to or after melittin administration. The results showed that both pre- and post-treatment of capsazepine could significantly prevent and suppress the melittin-induced ongoing nociceptive responses and thermal hypersensitivity, but were without influencing mechanical hypersensitivity. The present results suggest that the naturally occurring peptidergic substances of the whole honeybee venom have various pharmacological potencies to produce local inflammation, nociception and pain hypersensitivity in mammals, and among the five identified reverse-phase high pressure liquid chromatography subfractions (four polypeptides), melittin, a polypeptide occupying over 50% of the whole honeybee venom, plays a central role in production of local inflammation, nociception and hyperalgesia or allodynia following the experimental honeybee's sting. Peripheral transient receptor potential vanilloid receptor 1 is likely to be involved in melittin-produced ongoing pain and heat hyperalgesia, but not mechanical hyperalgesia, in rats.

Amino Acid Sequence↗

PubMed2006

Inflammation increases the excitability of masseter muscle afferents.

Temporomandibular disorder is a major health problem associated with chronic orofacial pain in the masticatory muscles and/or temporomandibular joint. Evidence suggests that changes in primary afferents innervating the muscles of mastication may contribute to temporomandibular disorder. However, there has been little systematic study of the mechanisms controlling the excitability of these muscle afferents, nor their response to inflammation. In the present study, we tested the hypotheses that inflammation increases the excitability of sensory neurons innervating the masseter muscle of the rat and that the ionic mechanisms underlying these changes are unique to these neurons. We examined inflammation-induced changes in the excitability of trigeminal ganglia muscle neurons following intramuscular injections of complete Freund's adjuvant. Three days after complete Freund's adjuvant injection acutely dissociated, retrogradely labeled trigeminal ganglia neurons were studied using whole cell patch clamp techniques. Complete Freund's adjuvant-induced inflammation was associated with an increase in neuronal excitability marked by a significant decrease in rheobase and increase in the slope of the stimulus response function assessed with depolarizing current injection. The increase in excitability was associated with significant decreases in the rate of action potential fall and the duration of the action potential afterhyperpolarization. These changes in excitability and action potential waveform were associated with significant shifts in the voltage-dependence of activation and steady-state availability of voltage-gated K(+) current as well as significant decreases in the density of voltage-gated K(+) current subject to steady-state inactivation. These data suggest that K(+) channel subtypes may provide novel targets for the treatment of pain arising from inflamed muscle. These results also support the hypothesis that the underlying mechanisms of pain arising from specific regions of the body are unique suggesting that it may be possible, if not necessary to treat pain originating from different parts of the body with specific therapeutic interventions.

4-Aminopyridine↗

PubMed2006

Interleukin-1 beta contributes to the upregulation of kappa opioid receptor mrna in dorsal root ganglia in response to peripheral inflammation.

During local painful inflammation, axonal transport of opioid receptors from dorsal root ganglia toward the periphery is increased, associated with a higher receptor density and enhanced efficacy of opioid analgesics at the injured site. To examine whether this increase is related to transcription, mRNA of the kappa opioid receptor in lumbar dorsal root ganglia was quantified by real time light cycler polymerase chain reaction. In dorsal root ganglia of naive rats, kappa opioid receptor mRNA expression was three-fold higher than previously shown for delta opioid receptor and two times lower than mu opioid receptor mRNA, respectively. After induction of unilateral paw inflammation by Freund's complete adjuvant, kappa opioid receptor mRNA was significantly upregulated with a peak at 12 h in ipsilateral dorsal root ganglia. This effect could be mimicked by intraplantar injection of the proinflammatory cytokine interleukin-1 beta. Kappa opioid receptor mRNA upregulation lasted longer in interleukin-1 beta-treated rats compared with Freund's complete adjuvant-treated rats. Furthermore, a significant increase in kappa opioid receptor positive neurons was detected by immunohistochemistry 24 h after local injection of Freund's complete adjuvant or interleukin-1 beta. In Freund's complete adjuvant-induced inflammation, kappa opioid receptor upregulation was blocked by treatment with interleukin-1 receptor antagonist without changing the leukocyte infiltration in the paw. In conclusion, kappa opioid receptor mRNA and protein in dorsal root ganglia are upregulated in response to peripheral inflammation. This effect can be mimicked by a single local injection of interleukin-1 beta, and Freund's complete adjuvant-induced upregulation in kappa opioid receptor mRNA and protein can be prevented by treatment with interleukin-1 receptor antagonist. These data suggest that the peripheral production of the proinflammatory cytokine interleukin-1 beta is a specific inducer of kappa opioid receptor expression in the dorsal root ganglia.

Animals↗

PubMed2005

Nitrative DNA damage in inflammation and its possible role in carcinogenesis.

Chronic inflammation has long been recognized as a risk factor for human cancer at various sites. Examples include Helicobacter pylori-induced gastritis for gastric cancer, inflammatory bowel disease (ulcerative colitis and Crohn's disease) for colorectal cancer and chronic viral hepatitis for liver cancer. Here we review the role in carcinogenesis of nitrative damage to nucleic acids, DNA and RNA, which occurs during inflammation through the generation of reactive nitrogen species, such as peroxynitrite, nitroxyl, and nitrogen dioxide. Enhanced formation of 8-nitroguanine, representative of nitrative damage to nucleobases, has been detected in various inflammatory conditions. The biochemical nature of DNA damage mediated by reactive nitrogen species is discussed in relation to its possible involvement in mutations, genetic instability, and cell death. Better understanding of the mechanisms and role of such nitrative damage in chronic inflammation-associated human cancer is a necessary basis to develop new strategies for cancer prevention by modulating the process of inflammation.

Chronic Disease↗