Biomedical subjects

Y Xu

Publications and source records attributed to Y Xu.

At least 163 records · Page 9Linked to original sources

PubMed2001

Altered expression of Ape1/ref-1 in germ cell tumors and overexpression in NT2 cells confers resistance to bleomycin and radiation.

The human AP endonuclease (Ape1 or ref-1) DNA base excision repair (BER) enzyme is a multifunctional protein that has an impact on a wide variety of important cellular functions including oxidative signaling, transcription factor regulation, and cell cycle control. It acts on mutagenic AP (baseless) sites in DNA as a critical member of the DNA BER repair pathway. Moreover, Ape1/ref-1 stimulates the DNA-binding activity of transcription factors (Fos-Jun, nuclear factor-kappaB, Myb, ATF/cyclic AMP-responsive element binding protein family, HIF-1alpha, HLF, PAX, and p53) through a redox mechanism and thus represents a novel component of signal transduction processes that regulate eukaryotic gene expression. Ape1/ref-1 has also been shown to be closely linked to apoptosis associated with thioredoxin, and altered levels of Ape1/ref-1 have been found in some cancers. In a pilot study, we have examined Ape1/ref-1 expression by immunohistochemistry in sections of germ cell tumors (GCTs) from 10 patients with testicular cancer of various histologies including seminomas, yolk sac tumors, and malignant teratomas. Ape1/ref-1 was expressed at relatively high levels in the tumor cells of nearly all sections. We hypothesized that elevated expression of Ape1/ref-1 is responsible in part for the resistance to therapeutic agents. To answer this hypothesis, we overexpressed the Ape1/ref-1 cDNA in the GCT cell line NT2/D1 using retroviral gene transduction with the vector LAPESN. Using an oligonucleotide cleavage assay and immunohistochemistry to assess Ape1/ref-1 repair activity and expression, respectively, we found that the repair activity and relative Ape1/ref-1 expression in GCT cell lines are directly related. NT2/D1 cells transduced with Ape1/ref-1 exhibited 2-fold higher AP endonuclease activity in the oligonucleotide cleavage assay, and this was reflected in a 2-3-fold increase in protection against bleomycin. Lesser protection was observed with gamma-irradiation. We conclude that: (a) Ape1/ref-1 is expressed at relatively high levels in some GCTs; (b) elevated expression of Ape1/ref-1 in testicular cancer cell lines results in resistance to certain therapeutic agents; and (c) Ape1/ref-1 expression in GCT cell lines determined by immunohistochemistry and repair activity assays parallels the level of protection from bleomycin. We further hypothesize that elevated Ape1/ref-1 levels observed in human testicular cancer may be related to their relative resistance to therapy and may serve as a diagnostic marker for refractory disease. To our knowledge, this is the first example of overexpressing Ape1/ref-1 in a mammalian system resulting in enhanced protection to DNA-damaging agents.

Antimetabolites, Antineoplastic↗

PubMed2001

Novel members of the human oxysterol-binding protein family bind phospholipids and regulate vesicle transport.

Oxysterol-binding proteins (OSBPs) are a family of eukaryotic intracellular lipid receptors. Mammalian OSBP1 binds oxygenated derivatives of cholesterol and mediates sterol and phospholipid synthesis through as yet poorly undefined mechanisms. The precise cellular roles for the remaining members of the oxysterol-binding protein family remain to be elucidated. In yeast, a family of OSBPs has been identified based on primary sequence similarity to the ligand binding domain of mammalian OSBP1. Yeast Kes1p, an oxysterol-binding protein family member that consists of only the ligand binding domain, has been demonstrated to regulate the Sec14p pathway for Golgi-derived vesicle transport. Specifically, inactivation of the KES1 gene resulted in the ability of yeast to survive in the absence of Sec14p, a phosphatidylinositol/phosphatidylcholine transfer protein that is normally required for cell viability due to its essential requirement in transporting vesicles from the Golgi. We cloned the two human members of the OSBP family, ORP1 and ORP2, with the highest degree of similarity to yeast Kes1p. We expressed ORP1 and ORP2 in yeast lacking Sec14p and Kes1p function and found that ORP1 complemented Kes1p function with respect to cell growth and Golgi vesicle transport, whereas ORP2 was unable to do so. Phenotypes associated with overexpression of ORP2 in yeast were a dramatic decrease in cell growth and a block in Golgi-derived vesicle transport distinct from that of ORP1. Purification of ORP1 and ORP2 for ligand binding studies demonstrated ORP1 and ORP2 did not bind 25-hydroxycholesterol but instead bound phospholipids with both proteins exhibiting strong binding to phosphatidic acid and weak binding to phosphatidylinositol 3-phosphate. In Chinese hamster ovary cells, ORP1 localized to a cytosolic location, whereas ORP2 was associated with the Golgi apparatus, consistent with our vesicle transport studies that indicated ORP1 and ORP2 function at different steps in the regulation of vesicle transport.

Amino Acid Sequence↗

PubMed2001

The FadR.DNA complex. Transcriptional control of fatty acid metabolism in Escherichia coli.

In Escherichia coli, the expression of fatty acid metabolic genes is controlled by the transcription factor, FadR. The affinity of FadR for DNA is controlled by long chain acyl-CoA molecules, which bind to the protein and modulate gene expression. The crystal structure of FadR reveals a two domain dimeric molecule where the N-terminal domains bind DNA, and the C-terminal domains bind acyl-CoA. The DNA binding domain has a winged-helix motif, and the C-terminal domain resembles the sensor domain of the Tet repressor. The FadR.DNA complex reveals how the protein interacts with DNA and specifically recognizes a palindromic sequence. Structural and functional similarities to the Tet repressor and the BmrR transcription factors suggest how the binding of the acyl-CoA effector molecule to the C-terminal domain may affect the DNA binding affinity of the N-terminal domain. We suggest that the binding of acyl-CoA disrupts a buried network of charged and polar residues in the C-terminal domain, and the resulting conformational change is transmitted to the N-terminal domain via a domain-spanning alpha-helix.

Acyl Coenzyme A↗

PubMed2001

Expression studies on clustered trypanosomatid box C/D small nucleolar RNAs.

We analyzed three chromosomal loci of the trypanosomatid Leptomonas collosoma encoding box C/D small nucleolar RNAs (snoRNAs). All the snoRNAs that were analyzed here carry two sequences complementary to rRNA target sites and obey the +5 rule for guide methylation. Studies on transgenic parasites carrying the snoRNA-2 gene in the episomal expression vector (pX-neo) indicated that no promoter activity was found immediately adjacent to this gene. Deleting the flanking sequences of snoRNA-2 affected the expression; in the absence of the 3'-flanking (but not 5'-flanking) sequence, the expression was almost completely abolished. The snoRNA genes are transcribed as polycistronic RNA. All snoRNAs can be folded into a common stem-loop structure, which may play a role in processing the polycistronic transcript. snoRNA B2, a member of a snoRNA cluster, was expressed when cloned into the episomal vector, suggesting that each gene within a cluster is individually processed. Studies with permeable cells indicated that snoRNA gene transcription was relatively sensitive to alpha-amanitin, thus supporting transcription by RNA polymerase II. We propose that snoRNA gene expression, similar to protein-coding genes in this family, is regulated at the processing level.

Amanitins↗

PubMed2001

Membrane ion-exchange chromatography for process-scale antibody purification.

The large-scale production of recombinant monoclonal antibodies demands economical purification processes with high throughputs. The potential for ion-exchange membrane adsorbers to replace traditional ion-exchange columns was evaluated. Breakthrough capacities of commercially available cation-exchange membranes were determined as a function of flow-rate and layer number. Due to economic and process restrictions, cation-exchange membranes may not currently be advantageous for process-scale antibody purification in a bind and elute mode. However, anion-exchange membranes in a flow-through mode may provide a reasonable alternative to columns for the removal of low levels of impurities such as DNA, host cell protein, and virus.

Antibodies↗

PubMed2001

Nuclear factor kappaB-dependent mechanisms coordinate the synergistic effect of PMA and cytokines on the induction of superoxide dismutase 2.

Manganese superoxide dismutase (MnSOD) serves a protective role under conditions of oxidative stress mediated by such diverse agents as adriamycin, radiation, chemical hypoxia and ischaemia and might act as a newly recognized type of tumour-suppressor. MnSOD is an inducible enzyme; however, the signalling molecules and pathways involved in its induction have not been fully elucidated. Recently we reported the identification of a 342 bp enhancer within the second intron (I2E) of the human gene encoding MnSOD (SOD2), which contains sites for binding nuclear factor kappaB (NF-kappaB), CCAAT-enhancer-binding protein (C/EBP) and nuclear factor 1 (NF-1). Using a human fibroblast cell line transformed by simian virus 40, we have identified the I2E fragment as being responsive to PMA. Furthermore, simultaneous treatment with PMA and cytokines (tumour necrosis factor alpha and interleukin 1beta) synergistically increases MnSOD induction. The use of mutant constructs identified the NF-kappaB element within the enhancer fragment as being essential for the PMA and PMA/cytokine effect. Mutations in the C/EBP- and NF-1-binding sites revealed a potential co-operation between proteins that bind to these sites and the NF-kappaB element. Evaluation of inhibitory kappaB (IkappaB)-alpha and IkappaB-beta proteins reveals agent-specific differences in their turnover kinetics. Both C/EBP and NF-kappaB DNA-binding activities were increased in cells receiving a combination of cytokine and PMA. Supershift and immunoprecipitation studies suggest a physical interaction between C/EBP and NF-kappaB proteins. Taken together, these studies suggest the activation of multiple transcription factors as well as pathways leading to increased NF-kappaB activity as being the mechanisms responsible for the synergistic induction of MnSOD by PMA and cytokines.

CCAAT-Enhancer-Binding Proteins↗

PubMed2001

FLAIR histogram segmentation for measurement of leukoaraiosis volume.

The purposes of this study were to develop a method to measure brain and white matter hyperintensity (leukoaraiosis) volume that is based on the segmentation of the intensity histogram of fluid-attenuated inversion recovery (FLAIR) images and to assess the accuracy and reproducibility of the method. Whole-head synthetic image phantoms with manually introduced leukoaraiosis lesions of varying severity were constructed. These synthetic image phantom sets incorporated image contrast and anatomic features that mimicked leukoaraiosis found in real life. One set of synthetic image phantoms was used to develop the segmentation algorithm (FLAIR-histoseg). A second set was used to measure its accuracy. Test retest reproducibility was assessed in 10 elderly volunteers who were imaged twice. The mean absolute error of the FLAIR-histoseg method was 6.6% for measurement of leukoaraiosis volume and 1.4% for brain volume. The mean test retest coefficient of variation was 1.4% for leukoaraiosis volume and 0.3% for brain volume. We conclude that the FLAIR-histoseg method is an accurate and reproducible method for measuring leukoaraiosis and whole-brain volume in elderly subjects.

Aged↗

PubMed2001

Partial Fourier imaging in multi-dimensions: a means to save a full factor of two in time.

We present an improvement to the traditional one-dimensional partial Fourier method by extending the method to multi-dimensions. The modified method allowed a full factor of two savings in time with much better coverage of the central k-space information and, because of this, smaller reconstruction artifacts. The residual magnitude error was found to correlate strongly with the residual phase error. Numerical simulation also indicated that with a priori perfect phase information, the original magnitude image could be perfectly reconstructed with half of the k-space data points in the multi-dimensional case. Simulated, phantom, and human data sets were tested with edge differences ranging from 10% (consistent with variable Gibbs ringing) to 25% (consistent with a blurred version of the object). The method was found to be a valuable adjunct to human imaging for short TR, T1-weighted three-dimensional gradient-echo imaging and magnetic resonance (MR) angiographic methods, especially when short echo times were used.

Algorithms↗

PubMed2001

Application of PROSPECT in CASP4: characterizing protein structures with new folds.

In the Fourth Community Wide Experiment on the Critical Assessment of Techniques for Protein Structure Prediction (CASP4), we predicted all 43 targets using our threading application PROSPECT. PROSPECT guarantees to find an optimal alignment between a protein sequence and a structural fold for a general energy function with pairwise contact potential. For each prediction, it gives a reliability assessment based on a neural network approach. In addition, PROSPECT has been added to the Genomic Integrated Supercomputing Toolkit (GIST) and is deployed on terascale computing resources. Structural predictions in CASP4 included three categories, that is comparative modeling, fold recognition, and prediction for structures with new folds. In the fold recognition category, PROSPECT correctly identified 8 of a total of 22 and finished the sixth in the total scores among 127 assessed groups. In the "new fold" category, it found important structural features for most targets, and its overall performance is among the best of all prediction methods. Our CASP4 performance demonstrates that PROSPECT is a powerful tool to quickly characterize structures with new folds, and it may provide useful structural restraints for ab initio prediction methods.

Computer Simulation↗

PubMed2001

Electrospray ionization mass spectrometry analysis of lysophospholipids in human ascitic fluids: comparison of the lysophospholipid contents in malignant vs nonmalignant ascitic fluids.

Lysophospholipids (lyso-PLs), including various glycerol-based and sphingosine-based lysophospholipids, play important roles in many biochemical, physiological, and pathological processes. The classical methods to analyze these lipids involve gas chromatography and/or high-performance liquid chromatography, which are time-consuming, cumbersome, and sometimes inaccurate due to the incomplete separation of closely related lipid species. We now describe the quantitative analysis of lyso-PLs in ascites samples from patients with ovarian cancer using electrospray ionization spectrometry. Three new classes of lyso-PL molecules are detected: alkyl-LPA, alkenyl-LPA, and methylated lysophosphatidylethanolamine. Importantly, the following lysophospholipid species are significantly increased in ascites from patients with ovarian cancer, compared to patients with nonmalignant diseases (e.g., liver failure): LPA (including acyl-, alkyl-, and alkenyl-LPA species), lysophosphatidylinositol, and sphingosylphosphorylcholine. Lysophosphorylcholine contents are also significantly different among ascitic fluids from the two groups of patients. However, the total phosphate content in ascites samples from patients with ovarian cancer is not significantly different compared to that from patients with nonmalignant disease.

Ascites↗

PubMed2001

Long-term toxic impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the reproduction, sexual differentiation, and development of different life stages of Gobiocypris rarus and Daphnia magna.

The sexual ratio of Gobiocypris rarus exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 17 beta-estradiol from embryo to sexually mature revealed feminization and overdevelopment of connective tissue in male fish gonad in 2--30 pg/L TCDD concentration range. Daphnia magna was not sensitive to the high dose of TCDD (0.1--1000 ng/ml), but the reproduction of D. magna treated with TCDD decreased after the 8th day. 7-Ethoxyresorufin-O-deethylase (EROD) activities in newly fertilized eggs of G. rarus exposed to TCDD dosage groups (1000--100,000 pg/L) were significantly induced and increased with TCDD concentrations at the early life stage, while no difference was found between low TCDD dosage groups (<100 pg/L), but a good relationship between the EROD activity and the TCDD concentration was observed during a long-term developmental stage. There was a pericardial edema formed in a 2-week yolk-sac at the concentration of 1000 pg/L TCDD. But in the exposure group (2 pg/L TCDD for 120 days), the cell nuclei of hepatocytes was far from the center and packed toward the cell membrane; the cristae of most mitochondria in the cell dropped and collapsed; the rough endoplasmic reticulum broke into fragments; and numerous lipid droplets formed in the cell.

Animals↗

PubMed2001

Lysophospholipids increase interleukin-8 expression in ovarian cancer cells.

OBJECTIVES: We have previously described that bioactive lysophospholipids-lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P), and sphingosylphosphorylcholine (SPC)-are present in ascitic fluids from patients with ovarian cancer. To understand the role of these lipids in ovarian cancer, we investigated the effects of these lipids on interleukin-8 (IL-8) production in ovarian cancer cells. IL-8 is a proinflammatory and proangiogenic factor, which is potentially involved in ovarian cancer development. METHODS: The Clontech PCR-Select cDNA subtraction method (Clontech Laboratories, Inc., Palo Alto, CA) was used to identify genes potentially regulated by LPA in HEY and OCC1 ovarian cancer cell lines. Northern blot analysis was used to confirm and examine IL-8 mRNA regulation by lysolipids. Enzyme-linked immunosorbent assay (ELISA) was used for detecting secreted IL-8. RESULTS: We describe here that LPA, S1P, and SPC increased mRNA levels (2- to 7-fold) and protein secretion (2- to 12-fold) of IL-8 from ovarian cancer cells (HEY, OCC1, and SKOV3) in vitro. These regulations were both dose- and time-dependent. All three lipids increased the stability IL-8 mRNA in HEY cells. In contrast to malignant ovarian cancer cells, immortalized human ovarian epithelial cells did not respond to any of these lipids to increase the secretion of IL-8, although these cells secreted similar basal levels of IL-8 (310 pg/ml/10,000 cells). Two breast cancer cell lines (MCF7 and T47D) secreted lower basal levels of IL-8 (48-80 pg/ml/10,000 cells), compared with ovarian cancer cells (200-500 pg/ml/10,000 cells). MCF7 cells responded to LPA, but not S1P and SPC, by increasing the secretion of IL-8. T47D and MCF10A, an immortalized breast cell line, did not respond to LPA, S1P, or SPC to increase IL-8 secretion. CONCLUSIONS: LPA, S1P, and SPC regulate the mRNA and protein levels of the proinflammatory and proangiogenic factor IL-8 in ovarian cancer cells. The pathological significance of these regulations in ovarian cancer remains to be further investigated.

Dose-Response Relationship, Drug↗

PubMed2001

Fatty acid composition of lysophosphatidic acid and lysophosphatidylinositol in plasma from patients with ovarian cancer and other gynecological diseases.

OBJECTIVE: We previously reported that plasma levels of total lysophosphatidic acid (LPA) represented a potential biomarker for ovarian cancer and other gynecological cancers [1]. However, total LPA is composed of different LPA species with distinct fatty acid chains. The major objective of the current study, therefore, was to determine whether one or more specific fatty acid LPA species was associated with disease or disease staging. If this was determined, these species could be useful in further improving the sensitivity and/or specificity of this biomarker for the diagnosis and/or prognosis of the disease. Because lysophosphatidylinositol (LPI) co-migrates with LPA, this study represents the analysis of combined molecular species from both lysolipid classes. METHODS: The patient population, sample collection, and analyses have been reported previously [1]. Lipids were hydrolyzed from the LPA band on thin-layer chromatography plates. The following individual fatty acid species were analyzed by gas chromatography: palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2), arachidonic acid (20:4), and docosahexaenoic acid (22:6). The LPA/LPI fatty acid composition levels were analyzed and compared with disease status. RESULTS: Distinct plasma LPA/LPI fatty acid chain species were not associated with ovarian or other gynecological cancers, compared to patients with benign gynecological disease or healthy controls. However, an increased presence of unsaturated fatty acids in plasma LPA/LPI was found in patients with late-stage or recurrent ovarian cancer and possibly with other gynecological cancers. CONCLUSIONS: Analysis of individual fatty acid species present in plasma LPA/LPI do not appear to enhance the sensitivity or specificity of total LPA/LPI as a marker for gynecological cancer detection. However, our results suggest that increased LPA/LPI species with unsaturated fatty acid chains may be associated with late-stage or recurrent ovarian cancer.

Adult↗

PubMed2001

Automatic assignment of NOESY cross peaks and determination of the protein structure of a new world scorpion neurotoxin using NOAH/DIAMOD.

The 3D NMR structures of the scorpion neurotoxin, CsE-v5, were determined from the same NOESY spectra with NOAH/DIAMOD, an automated assignment and 3D structure calculation software package, and with a conventional manual assignment combined with a distance geometry/simulated annealing (X-PLOR) refinement method. The NOESY assignments and the 3D structures obtained from the two independent methods were compared in detail. The NOAH/DIAMOD program suite uses feedback filtering and self-correcting distance geometry methods to automatically assign NOESY spectra and to calculate the 3D structure of a protein. NOESY cross peaks were automatically picked using a standard software package and combined with 74 manually assigned NOESY peaks to start the NOAH/DIAMOD calculations. After 63 NOAH/DIAMOD cycles, using REDAC procedures in the last 8 cycles, and final FANTOM constrained energy minimization, a bundle of 20 structures with the smallest target functions has a RMSD of 0.81 A for backbone atoms and 1.11 A for all heavy atoms to the mean structure. Despite some missing chemical shifts of side chain protons, 776 (including 74 manually assigned) of 1130 NOE peaks were unambiguously assigned, 150 peaks have more than one possible assignment compatible with the bundle structures, and only 30 peaks could not be assigned within the given chemical shift tolerance ranges in either the D1 or the D2 dimension. The remaining 174, mainly weak NOE peaks were not compatible with the final 20 best bundle structures at the last NOAH/DIAMOD cycle. The automatically determined structures agree well with the structures determined independently using the conventional method and the same NMR spectra, with the mean RMSD in well-defined regions of 0.84 A for bb and 1.48 A for all heavy atoms from residues 2-5, 18-26, 32-36, and 39-45. This study demonstrates the potential of the NOAH/DIAMOD program suite to automatically assign NMR data for proteins and determine their structure.

Amino Acids↗

PubMed2001

The effect of Erigeron breviscapus on proliferation of pulmonary artery smooth muscle cells in hypoxic porcines.

In order to study the effect of Erigeron Breviscapus (EB) on proliferation of pulmonary artery smooth muscle cells (PASMC) in hypoxic porcines, immunohistochemical and MTT methods were employed to measure the proliferation of PASMC. It was found that the proliferation of PASMC in porcines was obvious, and the expression of proliferating cell nuclear antigen (PCNA) was significantly high within 48 h after exposure to hypoxia. The EB could inhibit the proliferation and the expression of PCNA in PASMC under hypoxia, but it had no effect on the proliferation and expression of PCNA in PASMC under normal condition. The EB could inhibit the proliferation and the expression of PCNA in PASMC induced by phorbol 12-myristate 13-acetate (PMA), an agonist of PKC in normal and hypoxic conditions. It was concluded that the hypoxia could enhance the proliferation and expression of PCNA in PASMC. The EB can inhibit the proliferation and expression of PCNA in PASMC under hypoxia through PKC-signal way. The EB may be used in treating the pulmonary hypertension by inhibiting the proliferation of PASMC and the pulmonary vascular remodeling.

Animals↗

PubMed2001

Experimental study of serum substantia nigra neuron autoantibody and its effect in Parkinson disease patients.

To investigate the serum substantia nigra neuron autoantibody and its effect in the patients with Parkinson disease (PD), substantia nigra slices and a rat model of injection of serum from PD patients in unilateral side substantia nigra were applied. The results showed that the positive rate of substantia nigra neuron autoantibody in PD patients was significantly higher than in the healthy control group (36.67% vs 6.67%, P < 0.01), but no significant difference was found between PD group and myasthenia gravis (MG) group (26.67%, P > 0.05). The sera from PD patients positive for substantia nigra neuron autoantibody could decrease the number of the dopaminergic neurons more seriously than those from MG and the healthy once respectively (both P < 0.01). The results suggested that the immunological mechanism might partly play a role in the development of PD.

Adult↗

PubMed2001

An experimental study on the regulation of expression of Th2 cytokines from T lymphocytes by protein kinase C in asthma.

To explore the regulatory role of protein kinase C (PKC) in the expression of Th2 cytokines, interleukin-4 (IL-4) and interleukin-5 (IL-5) by T lymphocytes in asthma. T lymphocytes were isolated and purified from blood and bronchial alveolus lavage fluid (BALF) of each guinea pig of normal control group and asthmatic group and from peripheral blood of the asthmatic patients and normal controls, and were stimulated with PKC accelerant phorbol 12-myristate 13-acetate (PMA) and inhibitor Ro31-8220. The expression of IL-4 and IL-5 mRNA and protein was detected by using in situ hybridization staining and ELISA respectively. The expression of IL-4 and IL-5 mRNA and protein of asthmatic T lymphocytes stimulated with PMA was significantly higher than that of asthmatic T lymphocytes stimulated without PMA respectively (P < 0.01) and that of normal T lymphocytes stimulated with PMA respectively (P < 0.01). The expression of IL-4 and IL-5 mRNA and protein of asthmatic T lymphocytes stimulated with PMA and Ro31-8220 was significantly lower than that of asthmatic T lymphocytes stimulated only with PMA respectively (P < 0.01). It was concluded that PKC might participate in regulating the expression of IL-4 and IL-5 in asthmatic T lymphocytes, and the activation of PKC in T lymphocytes might play an important role in the pathogenesis of asthma.

Adult↗

PubMed2001

mRNA expression of basic fibroblast growth factor from a single intratracheal instillation of papain-induced emphysema in rats.

The relations between mRNA expression of basic fibroblast growth factor (bFGF) and the changes in collagen I and collagen III in pulmonary tissues from a single intratracheal instillation of papain-induced emphysema in rats were investigated. Wistar rats (n = 42) were randomly divided into normal group and emphysema model 1, 3, 5, 7, 15, 30-day groups (n = 6 in each group). The rat model of emphysema was induced by a single intratracheal instillation of papain. The results of immunohistochemistry SABC and in situ hybridization with bFGF probe were quantitatively analyzed to examine the changes of collagen I and collagen III and bFGF mRNA expression in lung tissues and the percent of positive expression of bFGFmRNA in alveolar macrophages. The results were as follows: (1) In the emphysema model groups the optical densities of collagen I and collagen III began to increase after 3 days, reached the highest at the 7th day, and began to reduce at the 15th day; (2) No expression of bFGFmRNA in pulmonary tissues was detectable in the normal group. The positive expression of bFGFmRNA was detectable in lung tissues one day after the intratracheal instillation of papain. The average optical densities reached the peak (41.895 +/- 7.017) at the 7th day, significantly higher than in the normal group (0.581 +/- 0.139, P < 0.01). The positive expression of bFGFmRNA in lung tissues began to reduce at the 15th day; (3) Positive expression of bFGFmRNA in alveolar macrophages of instillation papain rats was detectable 3 days after the intratracheal instillation of papain, and reached the highest at the 7th day with the percent of positive expression of bFGF mRNA in alveolar macrophages being 70.13 +/- 11.21, higher than in the normal group (5.12 +/- 0.18, P < 0.01); (4) The expression of bFGF mRNA in the lung tissues and macrophages was positively related with the changes in collagen I and collagen III (P < 0.01 or P < 0.05) respectively. It was suggested that the up-regulation of bFGF mRNA expression during the development of emphysema can lead pulmonary interstitial fibrosis, which may take part in the injury and repair and the lung tissue reconstruction.

Animals↗