Biomedical subjects

Michael I Luster

Publications and source records attributed to Michael I Luster.

At least 19 recordsLinked to original sources

PubMed2006

Genetic susceptibility in pneumoconiosis.

A large number of cellular mediators such as cytokines, antioxidants and growth factors have been implicated in the pathogenesis of chronic inflammatory and fibrotic diseases. Common functional polymorphisms in these genes have been shown to influence individual susceptibility to these diseases. Silicosis, coal worker pneumoconiosis, progressive massive fibrosis and berylliosis are examples of fibrotic pneumoconiosis and are characterized by irreversible fibrotic lesions in the lung resulting from chronic dust inhalation. Although the materials are the major contributory factors of the disease pathogenesis, not all individuals exposed to similar levels develop disease. This suggests that there is a genetic predisposition to their development. Therefore, an understanding of genetic variability and the interaction between genetic and environmental factors is crucial to the identification of high-risk individuals and prevention and treatment of these diseases.

Air Pollutants, Occupational↗

PubMed2006

Immunotoxicogenomics: the potential of genomics technology in the immunotoxicity risk assessment process.

Evaluation of xenobiotic-induced changes in gene expression as a method to identify and classify potential toxicants is being pursued by industry and regulatory agencies worldwide. A workshop was held at the Research Triangle Park campus of the Environmental Protection Agency to discuss the current state-of-the-science of "immunotoxicogenomics" and to explore the potential role of genomics techniques for immunotoxicity testing. The genesis of the workshop was the current lack of widely accepted triggering criteria for Tier 1 immunotoxicity testing in the context of routine toxicity testing data, the realization that traditional screening methods would require an inordinate number of animals and are inadequate to handle the number of chemicals that may need to be screened (e.g., high production volume compounds) and the absence of an organized effort to address the state-of-the-science of toxicogenomics in the identification of immunotoxic compounds. The major focus of the meeting was on the theoretical and practical utility of genomics techniques to (1) replace or supplement current immunotoxicity screening procedures, (2) provide insight into potential modes or mechanisms of action, and (3) provide data suitable for immunotoxicity hazard identification or risk assessment. The latter goal is of considerable interest to a variety of stakeholders as a means to reduce animal use and to decrease the cost of conducting and interpreting standard toxicity tests. A number of data gaps were identified that included a lack of dose response and kinetic data for known immunotoxic compounds and a general lack of data correlating genomic alterations to functional changes observed in vivo. Participants concluded that a genomics approach to screen chemicals for immunotoxic potential or to generate data useful to risk assessors holds promise but that routine use of these methods is years in the future. However, recent progress in molecular immunology has made mode and mechanism of action studies much more practical. Furthermore, a variety of published immunotoxicity studies suggest that microarray analysis is already a practical means to explore pathway-level changes that lead to altered immune function. To help move the science of immunotoxicogenomics forward, a partnership of industry, academia, and government was suggested to address data gaps, validation, quality assurance, and protocol development.

Animals↗

PubMed2006

Deficiency of TNF receptors suppresses microglial activation and alters the susceptibility of brain regions to MPTP-induced neurotoxicity: role of TNF-alpha.

Enhanced expression of tumor necrosis factor (TNF) -alpha, is associated with the neuropathological effects underlying disease-, trauma- and chemically induced neurodegeneration. Previously, we have shown that deficiency of TNF receptors protects against MPTP-induced striatal dopaminergic neurotoxicity, findings suggestive of a role for TNF-alpha in neurodegeneration. Here, we demonstrate that deficiency of TNF receptors suppresses microglial activation and alters the susceptibility of brain regions to MPTP. MPTP-induced expression of microglia-derived factors, TNF-alpha, MCP-1, and IL-1alpha, preceded the degeneration of striatal dopaminergic nerve terminals and astrogliosis, as assessed by loss of striatal dopamine and TH, and an increase in striatal GFAP. Pharmacological neuroprotection with the dopamine reuptake inhibitor, nomifensine, abolished striatal dopaminergic neurotoxicity and associated microglial activation. Similarly, in mice lacking TNF receptors, microglial activation was suppressed, findings consistent with a role for TNF-alpha in striatal MPTP neurotoxicity. In the hippocampus, however, TNF receptor-deficient mice showed exacerbated neuronal damage after MPTP, as evidenced by Fluoro Jade-B staining (to identify degenerating neurons) and decreased microtubule-associated protein-2 (MAP-2) immunoreactivity. These effects were not accompanied by microglial activation, but were associated with increased oxidative stress (nitrosylation of tyrosine residues). These findings suggest that TNF-alpha exerts a neurotrophic/neuroprotective effect in hippocampus. The marked differences we observed in the regional density, distribution and/or activity of microglia and microglia-derived factors may influence the region-specific role for this cell type. Taken together, our results are indicative of a region-specific and dual role for TNF-alpha in the brain: a promoter of neurodegeneration in striatum and a protector against neurodegeneration in hippocampus.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2005

Maternal treatment with a high dose of CpG ODN during gestation alters fetal craniofacial and distal limb development in C57BL/6 mice.

Synthetic oligodeoxynucleotides (ODN) containing CpG motifs, characteristic of bacterial DNA, are currently being evaluated as vaccine adjuvants for inducing protective immunity. Recently, there is increasing pressure to vaccinate pregnant women against maternally transmitted diseases including AIDS and tetanus, as well as against potential bio-weapons such as anthrax. CpG vaccines are effective because they trigger transient increases in T(H)1 cytokine production. Recent literature suggests, however, that a shift toward a T(H)1 cytokine profile during pregnancy may increase the risk of fetal morphologic defects. On this basis, we hypothesized that exposure to CpG motifs during pregnancy could result in T(H)1 inflammation leading to adverse effects on fetal development. To address this hypothesis, pregnant C57BL/6 mice were injected with CpG ODN (0-300 microg/dam) and maternal and fetal outcomes were determined. Injection of dams with the highest dose of CpG ODN resulted in markedly increased fetal resorptions and craniofacial/limb defects, while lower doses had little, if any effects. Histological examination of placentas revealed cellular necrosis with mixed inflammation and calcification in the spongiotrophoblast layer and dysregulation of labyrinthine vascular development. Concomitant elevations in maternal serum cytokine levels were observed including interleukin (IL)-2, IL-10 and IL-12. Treatment with 300 microg of non-CpG ODN did not cause any adverse effects. The 300 microg dose of CpG ODN used in the present study is 30-fold higher than the highest dose that has been administered to humans during clinical trials. These results suggest that the induction of T(H)1 cytokines during pregnancy by CpG motifs may potentially increase the risk of fetal loss and morphologic defects in mice, at least at high doses, and support the need for further investigation of teratogenesis that may result from exposure to vaccine adjuvants designed to produce T(H)1 cytokine profile shifts.

Animals↗

PubMed2005

Biomarkers to assess potential developmental immunotoxicity in children.

Clinical tests are readily available for assessing severe loss of immune function in children with diseases such as AIDS or primary immunodeficiency. However tests that could reliably identify subtle immune changes, as might be expected to result from exposure to developmental immunotoxic agents, are not readily available. A number of tests are described which we believe have potential applicability for epidemiological studies involving developmental immunotoxicity. Several of the tests, such as T cell receptor rearrangement excision circles (TRECs) and cytokine measurements, while highly relevant from a biological standpoint, may be precluded from use at the current time, for either technical issues or insufficient validation. Immunophenotyping and measurement of serum immunoglobulin levels, on the other hand, are well validated. Yet they may require extraordinary care in experimental design and technical performance in order to obtain data that would consistently detect subtle changes, as these tests are not generally considered highly sensitive. Quantification of the immune response to childhood vaccine, while up to the present used sparingly, may represent an excellent indicator for developmental immunotoxicity when conducted under appropriate conditions.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Association of interleukin-1 gene polymorphisms with dementia in a community-based sample: the Honolulu-Asia Aging Study.

The interleukin-1 (IL-1) pro-inflammatory cytokine family participates in inflammatory processes and vessel damage involved in neurodegeneration. Recent studies suggest that Alzheimer's disease (AD) and vascular dementia (VaD) may share genetic risk factors. In this study, the frequency of polymorphisms in the genes coding for interleukin (IL)-1alpha, IL-1beta and the IL-1 receptor antagonist (RN) and their genotype associations with late-onset AD and VaD were determined in a Japanese-American cohort of men (n=931) participating in the Honolulu-Asia Aging Study (HAAS). A significant association was found between the IL-1beta (-511) and IL-1RN (+2018) polymorphisms and AD, suggesting that these variants confer an increased risk. Possessing the IL-1beta (-511) T/T genotype was also associated with VaD. There was no difference in the IL-1beta (+3953) frequency among the groups. Our results support the hypothesis that certain genetic variations contained within the IL-1 gene family contribute to the pathogenesis of dementia.

Aged↗

PubMed2005

Prevention of IL-1 signaling attenuates airway hyperresponsiveness and inflammation in a murine model of toluene diisocyanate-induced asthma.

BACKGROUND: IL-1 is a pleotropic cytokine that has been shown to play a prominent role in asthma induced by large-molecular-weight proteins. Increased IL-1 immunostaining in the submucosa of patients with toluene diisocyanate (TDI)-induced asthma has also been observed, suggesting that this cytokine might also be important in asthma associated with low-molecular-weight chemicals. OBJECTIVE: We sought to determine the role of IL-1 signaling in airway reactivity and inflammation by using a murine model of TDI-induced asthma. METHODS: C57BL/6 mice were exposed to TDI by means of vapor inhalation (20 ppb; 4 hours per day, 5 days per week, for 6 weeks) and then challenged 2 weeks later by inhalation with 20 ppb TDI vapor for 1 hour. RESULTS: Sensitized-challenged mice showed increased airway hyperresponsiveness (AHR), increased levels of TDI-specific IgG1 antibodies, airway epithelial thickening, inflammation consisting of infiltrating lymphocytes and eosinophils, and increased mRNA expression of IL-4, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 in the lung. Prevention of IL-1 signaling through deletion of the IL-1 receptor type I or administration of neutralizing antibodies to both IL-1beta and IL-1alpha abrogated the development of TDI-induced asthma. A partial reduction in AHR and TDI-specific IgG1 levels was observed in mice administered anti-IL-1beta, whereas anti-IL-1alpha had no effect on either parameter. Antibodies to IL-1beta or IL-1alpha alone blocked airway inflammation and the expression of IL-4 and adhesion molecules in the lung. CONCLUSIONS: These results suggest that IL-1 signaling is critical for AHR and airway inflammation, with IL-1beta and IL-1alpha having unique and overlapping roles in TDI-induced occupational asthma.

Animals↗

PubMed2004

Exposure and immunological determinants in a murine model for toluene diisocyanate (TDI) asthma.

Isocyanate-induced asthma, the most commonly reported cause of occupational asthma, has been difficult to diagnose and control, in part, because the biological mechanisms responsible for the disease and the determinants of exposure have been difficult to define. Appropriate animals models of isocyanate asthma will be instrumental to further our understanding of this disease. Previous studies have demonstrated that dermal exposure to isocyanates in mice results in systemic sensitization that leads to eosinophilic airways inflammation upon subsequent airway challenge. We hypothesized that inhalation of vapor phase toluene diisocyante (TDI) will lead to immunologic sensitization in mice and that subsequent challenge will induce pathology and immune system alterations indicative of asthma found in humans. To determine the impact of exposure dose as well as the involvement of immune (allergic) or nonimmune mechanisms, a murine model of TDI asthma was established and characterized following either low-level subchronic or high-dose acute inhalation TDI exposure. C57BL/6 J mice were exposed to TDI by inhalation either subchronically for 6 weeks (20 ppb, 4 h/day, 5 days/week) or by a 2-h acute exposure at 500 ppb. Both groups were challenged 14 days later via inhalation with 20 ppb TDI for 1 h. Mice that underwent the subchronic exposure regimen demonstrated a marked allergic response evidenced by increases in airway inflammation, eosinophilia, goblet cell metaplasia, epithelial cell alterations, airway hyperreponsiveness (AHR), T(H)1/T(H)2 cytokine expression in the lung, elevated levels of serum IgE, and TDI-specific IgG antibodies, as well as the ability to transfer these pathologies to naive mice with lymphocytes or sera from TDI exposed mice. In contrast, mice that received acute TDI exposure demonstrated increased AHR, specific IgG antibodies, and pathology in the lung consistent with asthma, but without the presence of elevated serum IgE, lung eosionophilia, or increased expression of T(H) cytokines. These results describe mouse models for TDI asthma consistent with that found in workers with occupational asthma and indicate that the pulmonary pathology associated with TDI can vary depending upon the exposure paradigm.

Adoptive Transfer↗

PubMed2004

Immune mediators in a murine model for occupational asthma: studies with toluene diisocyanate.

Isocyanate-induced asthma, which is the most common type of occupational asthma, has been difficult to diagnose and control, in part, because the biological mechanisms responsible for the disease and the determinants of exposure are not fully defined. To help address these issues, we recently established a murine model of toluene diisocyanate (TDI) asthma using inhalation exposure paradigms consistent with potential workplace exposure. In order to confirm our hypothesis that TDI-induce asthma, like allergic asthma, is predominantly a Th2 response, the ability of mice that were deficient in CD4 or CD8 cells or specific Th1 and Th2 cytokines to develop TDI asthma was examined. The development of allergic asthma was evaluated by monitoring lungs for the presence of eosinophilia, goblet cell metaplasia, epithelial cell alterations, airway hyperreactivity (AHR), and Th2 and Th1 cytokine expression, as well as serum IgE levels and TDI-specific IgG antibodies. Transgenic CD8 or CD4 knockout (KO) mice exhibited significant reductions in AHR, cytokine expression, serum antibody levels, airway inflammation, and histopathological lesions, although in a number of the endpoints the effects were more attenuated in CD4 KO mice. IFNgamma depletion ablated the increase in AHR in TDI-allergic mice, but had only slight to moderate effects on airway histopathology, serum antibody levels, and cytokine expression compared to sensitized/challenged controls. IL-4 and IL-13 deficiency had moderate inhibitory effects, while combined IL-4/IL-13 depletion effectively prevented almost all asthma-associated pathologies. Taken together, these results indicate that TDI asthma, like immune-mediated asthma produced by large-molecular-weight materials, is driven primarily by CD4+ T cells and is dependent upon the expression of Th2 cytokines. However, as with protein-induced asthma models, certain pathologies are influenced by CD8+ T cells and Th1-derived cytokines, such as AHR and cytokine production.

Allergens↗

PubMed2004

A proposed testing framework for developmental immunotoxicology (DIT).

A group of thirty immunotoxicology experts from the U.S. and E.U. representing government, industry, and academia met in May 2003, in Washington, D.C., to reach consensus regarding the most appropriate methods to assess developmental immunotoxicology (DIT) for hazard identification, including under what conditions such testing might be required. The following points represent the major conclusions from this roundtable discussion: (1) the rat is the preferred model; (2) any DIT protocol should be based on immune assays already validated; (3) DIT methods should be incorporated into standard developmental and reproductive toxicity protocols to the extent possible rather than a "stand-alone" protocol; (4) the approach to address DIT potential should be similar for chemicals and drugs, but the experimental design should be flexible and should reflect the specific questions to be answered; (5) it is possible to utilize a study design that assesses all critical windows in one protocol, with the results leading to further study of specific effects, as warranted; (6) animals should be exposed throughout the treatment protocol; (7) the triggers for DIT may include structure-activity-relationships, results from other toxicity studies, the intended use of a drug/chemical and/or its anticipated exposure of neonates and/or juveniles.

Animals↗

PubMed2004

Genotyping of single nucleotide polymorphisms in cytokine genes using real-time PCR allelic discrimination technology.

Single nucleotide polymorphisms (SNPs), particularly those within regulatory regions of genes that code for cytokines often impact expression levels and can be disease modifiers. Investigating associations between cytokine genotype and disease outcome provides valuable insight into disease etiology and potential therapeutic intervention. Traditionally, genotyping for cytokine SNPs has been conducted using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), a low throughput technique not amenable for use in large-scale cytokine SNP association studies. Recently, Taqman real-time PCR chemistry has been adapted for use in allelic discrimination assays. The present study validated the accuracy and utility of real-time PCR technology for a number of commonly studied cytokine polymorphisms known to influence chronic inflammatory diseases. We show that this technique is amenable to high-throughput genotyping and overcomes many of the problematic features associated with PCR-RFLP including post-PCR manipulation, non-standardized assay conditions, manual allelic identification and false allelic identification due to incomplete enzyme digestion. The real-time PCR assays are highly accurate with an error rate in the present study of <1% and concordance rate with PCR-RFLP genotyping of 99.4%. The public databases of cytokine polymorphisms and validated genotyping assays highlighted in the present study will greatly benefit this important field of research.

Base Sequence↗

PubMed2004

Symposium summary: children's health risk--what's so special about the developing immune system?

In recent years, there has been increasing regulatory pressure to protect the health of children, with the basic tenet being that children differ significantly from adults in their biological or physiological responses to chemical exposures. In a regulatory context, this has been translated to mean a requirement for an additional 10-fold safety factor for environmental contaminants, specialized tests, or both. Much of the initial focus has been on the developing endocrine and nervous systems; but increasingly, the developing immune system has been identified as a potential target organ for chemically mediated toxicity. More recently, the question has been raised regarding whether the current state of science supports the creation of developmental immunotoxicology (DIT) test guidelines. What is needed is a risk-based evaluation of the biology associated with the proposed differential sensitivity between children and adults and the impact of that assessment on additional regulatory measures to protect children in risk assessment analyses. Additionally, an understanding of whether the developing immune system shows greater susceptibility, either qualitatively or quantitatively, to chemical perturbation is critical. To address the question "What's so special about the developing immune system?" a symposium was organized for the 2003 Society of Toxicology annual meeting that brought together risk assessors, clinicians, immunologists, and toxicologists.

Adolescent↗

PubMed2004

Arsenic and urinary bladder cell proliferation.

Epidemiologic studies have demonstrated that a close association exists between the elevated levels of arsenic in drinking water and the incidence of certain cancers, including transitional cell carcinomas of the urinary bladder. We have employed in vitro and in vivo models to examine the effects of sodium arsenite on the urinary bladder epithelium. Mice exposed to 0.01% sodium arsenite in drinking water demonstrated hyperproliferation of the bladder uroepithelium within 4 weeks after initiating treatment. This occurred in the absence of amorphous precipitates and was accompanied by the accumulation of trivalent arsenite (iAs(3+)), and to a lesser extent dimethylarsenic (DMA), arsenate (iAs(5+)), and monomethylarsenic (MMA) in bladder tissue. In contrast to the bladder, urinary secretion was primarily in the form of DMA and MMA. Arsenic-induced cell proliferation in the bladder epithelium was correlated with activation of the MAP kinase pathway, leading to extracellular signal-regulated kinase (ERK) kinase activity, AP-1 activation, and expression of AP-1-associated genes involved in cell proliferation. Activation of the MAP kinase pathway involved both epidermal growth factor (EGF) receptor-dependent and -independent events, the latter involving Src activation. Studies summarized in this review suggest that arsenic accumulates in urinary bladder epithelium causing activation of specific signaling pathways that lead to chronic increased cell proliferation. This may play a non-epigenetic role in carcinogenesis by increasing the proliferation of initiated cells or increasing the mutational rate.

Animals↗

PubMed2004

Arsenic and atherosclerosis.

Epidemiological studies have demonstrated a correlation between environmental or occupational arsenic exposure and a risk of vascular diseases related to atherosclerosis. Studies summarized in this review suggest that arsenic induces endothelial dysfunction, including inflammatory and coagulating activity as well as impairs nitric oxide (NO) balance. This may provide the pathophysiological basis for atherogenic potential of arsenic. Consistent with these data, arsenic accelerates atherosclerosis in apolipoprotein E (ApoE) deficient mice, a model of human atherosclerosis.

Animals↗

PubMed2004

Role of CC chemokines in skeletal muscle functional restoration after injury.

The purpose of this study was to determine whether certain chemokines, which are highly expressed in injured skeletal muscle, are involved in the repair and functional recovery of the muscle after traumatic injury. In wild-type control mice, mRNA transcripts of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and monocyte chemoattractant protein (MCP)-1 as well as their major receptors, CCR5 and CCR2, increased after freeze injury and gradually returned to control (uninjured) levels by 14 days. Muscle function and histological characteristics were monitored in injured mice that were genetically deficient for the CCR5 receptor (a major receptor for MIP-1alpha and MIP-1beta) and also rendered MCP-1 deficient with neutralizing antibodies. To dissect the role of these chemokines, additional studies were conducted in CCR5- and CCR2-deficient mice. CCR5-/- mice injected with MCP-1 antiserum for the first 3 days after injury exhibited a twofold greater maximal isometric tetanic torque deficit at 14 days after injury than did controls (i.e., 33% vs. 17%; P = 0.002). The impaired functional recovery was accompanied with an increased fat infiltration within the regenerating muscle without a significant difference in the influx of inflammatory cells, including macrophages. Strength recovery was also impaired in mice deficient for the receptor of MCP-1, CCR2, but not in CCR5-/- mice that were not injected with MCP-1 antiserum. The data suggest that MCP-1/CCR2 plays a role in the regeneration and recovery of function after traumatic muscle injury.

Animals↗

PubMed2004

Animal models for diisocyanate asthma: answers for lingering questions.

PURPOSE OF REVIEW: Diisocyanates are the leading cause of occupational asthma, the most commonly reported lung disease associated with the workplace. Clinical studies have implicated the immune system in the pathogenesis of occupational asthma, but ethical and moral issues prevent mechanistic investigations in humans. For this reason, the development and characterization of animal models are germane to further understanding of diisocyanate occupational asthma and to identify avenues for therapeutic intervention. This review will highlight important features of existing experimental animal models with emphasis on new developments. RECENT FINDINGS: Experimental animal models of diisocyanate occupational asthma have demonstrated an immunological basis for the disease. Mice can be sensitized by dermal or respiratory exposure, suggesting that either exposure route may be important in the workplace. Recent findings show that sensitized mice develop airway hyperreactivity and inflammation, reflective of human disease. The transfer of lymphocytes or serum from sensitized mice can cause clinical disease in naive mice. Transgenic animals have identified a role for specific immunity, including the involvement of T-helper type 1/2 responses as well as CD4 and CD8 T cells in diisocyanate occupational asthma. Recent animal models have shown that sensitization can occur through subchronic inhalation of vapor-phase diisocyanate at levels as low as 20 ppb. SUMMARY: Recent progress using animal models has been instrumental in furthering current understanding of the involvement of the immune system in disease pathogenesis. The demonstration of diisocyanate occupational asthma in a murine model after sub-chronic inhalation exposure at relevant exposure levels should provide opportunities for more accurate risk assessment data.

Air Pollutants, Occupational↗

PubMed2003

Cytokine polymorphisms play a role in susceptibility to ultraviolet B-induced modulation of immune responses after hepatitis B vaccination.

UVB exposure can alter immune responses in experimental animals and humans. In an earlier human volunteer study, we demonstrated that hepatitis B-specific humoral and cellular immunity after vaccination on average were not significantly affected by UVB exposure. However, it is known that individuals differ in their susceptibility to UVB-induced immunomodulation, and it was hypothesized that polymorphisms in specific cytokines may play a role in this susceptibility. In this respect, we previously demonstrated that immune responses after hepatitis B vaccination are influenced by the minor allelic variant of IL-1 beta in the general population. For all volunteers, single nucleotide polymorphisms were determined for the following UV response-related cytokines: IL-1 receptor antagonist (+2018), IL-1 alpha (+4845), IL-1 beta (+3953), TNF-alpha (-308), and TNF-alpha (-238). Exposure to UVB significantly suppressed Ab responses to hepatitis B in individuals with the minor variant for the IL-1 beta polymorphism. Increased minimal erythema dose values (just perceptible), which resulted in higher absolute UVB exposures, were observed in the same individuals. There were no associations observed between UVB-induced immunomodulation and the other cytokine polymorphisms examined. This study indicates that individual susceptibility to UVB radiation needs to be considered when studying the effects of UVB in humans.

Adult↗

PubMed2003

Inflammatory mediators and skeletal muscle injury: a DNA microarray analysis.

Traumatic skeletal muscle injury causes a specific sequence of cellular events consisting of degeneration, inflammation, regeneration, and fibrosis. The role of early posttraumatic mechanisms, including acute inflammatory response, in muscle repair is not well understood. In the present study, oligonucleotide microarray analyses were used to examine the candidate genes that are involved in these early events of the muscle injury/repair process. cDNA was prepared from the injured and control tibialis anterior (TA) muscle of mice 24 h postinjury and labeled with the fluorescent dye Cy5 or Cy3 prior to hybridization to a DNA microarray. The microarray analysis, including 732 genes, was conducted in triplicate, and we describe only genes modulated by the injury showing a differential expression (both increased and decreased) 1.7-fold or greater (p < 0.05) from control uninjured TA muscle. Selected expression patterns were confirmed by other gene expression detection methods, including real-time reverse transcription-polymerase chain reaction (RT-PCR) and RNase protection assay (RPA) or immunohistochemistry detection methods. The upregulated genes (2.8%) were mainly associated with inflammation, oxidative stress, and cell proliferation, whereas the downregulated genes (3.2%) were related to metabolic and cell signaling pathways. In addition, the study suggested that chemokines, such as monocyte chemoattractant protein-1 (MCP-1), associated with monocyte/macrophage influx and activation, are abundantly expressed in postinjured muscle, and they might play a role in traumatic muscle injury/recovery processes.

Animals↗