Inhibition of latrunculin-A on dexamethasone-induced fibronectin production in cultured human trabecular meshwork cells

AIM: To determine the effects of a low dose latrunculin (LAT)-A on dexamethasone (Dex)-induced upregulation of extracellular matrix proteins fibronectin (FN) in cultured human trabecular meshwork (HTM) cells. METHODS: HTM cells were cultured to confluent and incubated with 0.4 mu mol/L Dex and/or 0.05 mu mol/L LAT-A. FN expression in HTM cells was evaluated by Western blot and immunofluorescence microscopy. RESULTS: Dex up-regulated FN production in HTM cells, failed to do so when co-incubated with LAT-A. LAT-A decreased production of FN in cultured HTM cells. CONCLUSION: This study indicated that LAT-A may modulate the expression of fibronectin in trabecular meshwork to achieve treatment for steroids and other types of glaucoma. It has an important prospect as an intraocular pressure-lowering drug.

Effect of Dexamethasone and Aquaporin-1 Antisense Oligonucleotides on the Aquaporin-1 Expression in Cultured Human Trabecular Meshwork Cells

The changes in the expression of aquaporin-1 （AQP1） mRNA and protein in cultured human trabecular meshwork （HTM） cells treated with dexamethasone and transfected with antisense oligonucleotides （AS-ODN） were studied, and the implication of AQP1 regulation in corticosteroid-glaucoma and the possibility of AS-ODN inhibiting the AQP1 expression were evaluated. The cultured HTM cells in vitro were treated with different concentrations of dexamethasone and transfected with oligonucleotides for 5 days respectively. Then, total RNA and protein of HTM cells were extracted. The changes of AQP1 mRNA and protein were demonstrated qualitatively and quantitatively by RT-PCR and Western blot. Band intensities were detected by imaging analysis. There was a parallel relationship between the results of RT-PCR and those of Western blot. The expression levels of AQP1 mRNA and protein in dexamethasone-treated groups were increased initially and decreased later as dexamethasone concentration was stepped up. In the 0.04 μg/mL and 0.4 μg/mL groups, the levels of AQP1 were higher than in control group （0 μg/mL）. In the 4 μg/ mL and 40 μg/mL groups, the AQP1 expression levels were lower than in control group. AS-ODN could down-regulate the expression of AQP1 mRNA and protein in a dose-dependent manner. At 5 μg/mL, down-regulation efficiency reached the maximum. There was no statistically significant difference in the expression of AQP1 mRNA and protein between all sense oligonucleotides groups and control group. It was suggested that dexamethasone may induce the changes of the AQP1 expression in HTM cells to be involved in the occurrence of corticosteroid-glaucoma. AS-ODN can down-regulate the AQP1 expression in HTM cells to some extent.

Effect of CD44 Suppression by Antisense Oligonucleotide on Attachment of Human Trabecular Meshwork Cells to HA

The effects of suppression of CD44 by CD44-specific antisense oligonucleotide on attachment of human trabecular meshwork cells to hyaluronic acid (HA) were observed and the possible relationship between CD44 and primary open-angle glaucoma (POAG) investigated. CD44-specific antisense oligonucleotide was delivered with cationic lipid to cultured human trabecular meshwork cells. The expression of CD44 suppressed by CD44-specific antisense oligonucleotide was detected by RT-PCR and Western blotting. The effect of CD44 suppression by specific antisense oligonucleotide on attachment of trabecular meshwork cells to HA was measured by MTT assay. Results showed that expression of CD44 was suppressed by CD44-specific antisense oligonucleotide. Antisense oligonucleotide also suppressed the adhesion of human trabecular meshwork cells to HA in a concentration dependent manner. It was concluded that attachment of human trabecular meshwork cells to HA was decreased when CD44 was suppressed by specific antisense oligonucleotide. CD44 might play a role in pathogenesis of POAG by affecting the adhesion of trabecular meshwork cells to HA.

Apoptosis of Human Trabecular Meshwork Cells Induced by Transforming Growth Factor-β_2 in vitro

Whether transforming growth factor β 2 (TGF β 2) induces apoptosis of human trabecular meshwork cells was investigated in vitro . Cultured 3 5 passage human trabecular meshwork cells were treated with 0 (control), 0.32, 1, 3.2 ng/ml TGF β 2 for 48 h and divided into control group and experimental group. The apoptosis of human trabecular meshwork cells was examined by transmisson electron microscopy, TUNEL technique and flow cytometry. The results showed characteristic morphologic changes of apoptotic cells were observed under transmission electron microscopy. DNA fragmentation of human trabecular meshwork cells was found by TUNEL technique. Quantitative analysis of flow cytometry showed that percentages of apoptotic human trabecular meshwork cells were (2.79±0.44) %, (4.43 ±1.17) % and (9.60±2.05) % respectively with different concentrations [1 ng/ml ( P< 0.05), 3.2 ng/ml ( P< 0.01)] of TGF β 2 with the difference being significant between experimental group and control group[(1.41±0.34) %]. It was concluded that TGF β 2 can induce apoptosis of human trabecular meshwork cells in vitro and may be involved in the decrease of trabecular meshwork cells in the patients with primary open angle glaucoma and aging of normal people.

Antagonistic Effects of Tranilast on Proliferation and Collagen Synthesis Induced by TGF-β_2 in Cultured Human Trabecular Meshwork Cells

Whether tranilast had antagonistic effect on proliferation inhibition and collagen synthesis promotion induced by TGF-β 2 in cultured human trabecular meshwork cells was investigated. Suspension of 1×104 cultured human trabecular meshwork cells of 3—5 passage was distributed in each well of a 96-well disk and divided into control group and experimental group. After 24 h, 0 μg/ml (control), 12.5 μg/ml, 25 μg/ml, 50 μg/ml tranilast with 3.2 ng/ml TGF-β 2 were added into the incubation medium. Another 24 h later, proliferation and collagen synthesis in cultured human trabecular meshwork cells were examined respectively by using tetrazolium-based semiautomated colormetric (MTT) assay and 3H-proline incorporation with liquid scintillation technique. The results showed absorbance (A) values of the experimental groups were 0.9036±0.3017, 1.1361± 0.1352, 1.2457±0.1524 according to the different concentrations of tranilast, and 0.8956± 0.1903 of the control group. In comparison with the control group, 25 μg/ml (q'=3.23, P< 0.05), 50 μg/ml (q'=4.70, P<0.01) tranilast significantly antagonized the decrease of the A values induced by TGF-β 2 in the cultured human trabecular meshwork cells. In comparison with the control group [817.37±124.21 cpm/104 cells], 12.5 μg/ml (620.33±80.46 cpm/104 cells, q'= 4.26, P< 0.05), 25 μg/ml (594.58±88.13 cpm/104 cells, q'=4.81, P<0.01), 50 μg/ml (418.64±67.90 cpm/104 cells, q'=8.62, P<0.01) tranilast significantly inhibited the incorporation of 3H-proline into the cultured human trabecular meshwork cells promoted by TGF-β 2 in a dose-dependent manner. It was concluded that tranilast had the antagonistic effect on the proliferation inhibition and collagen synthesis promotion induced by TGF-β 2 in the cultured human trabecular meshwork cells.

Transforming Growth Factor-β_2 Gene Cloning and Protein Expression in Human Trabecular Meshwork Cells

Whether cultured human trabecular meshwork cells express transforming growth factor-β 2 (TGF-β 2) messenger RNA (mRNA) and protein was investigated. Total RNA of 10 6 cultured human trabecular meshwork cells was extracted with TRIZOL reagent, reverse transcriptase-polymerase chain reaction (RT-PCR) were used for detection of TGF-β 2 messenger RNA, and the PCR product was verified by sequencing. Immunohistochemical staining was used to detect TGF-β 2 protein. The results showed that a single RT-PCR amplified product was obtained, and the sequence was homologous to the known sequence. TGF-β 2 immunostaining was positive. It was concluded that trabecular meshwork cells could produce TGF-β 2 and contribute to the presence of TGF-β 2 in trabecular meshwork microenvironment as well as aqueous humor. Trabecular meshwork cells were affected by TGF-β 2 not only through paracrine, but also autocrine action. Whether abnormal changes in TGF-β 2 production contribute to the pathogenesis of primary open-angle glaucoma is worth further investigation.

Effects of dexamethasone and HA1077 on actin cytoskeleton and β-catenin in cultured human trabecular meshwork cells

AIM：To investigate the effects of dexamethasone（DEX） and 1-（5-isoquinolinesulfonyl）-homopiperazine（HA1077） on actin cytoskeleton and β-catenin in cultured human trabecular meshwork（HTM） cells.METHODS： The HTM cells were separated from human eyeball and cultured in vitro.They were divided into control group,DEX（1×10^-6mol/L） group,HA1077（3×10^-5mol/L）group,and DEX（1×10^-6mol/L） and HA1077（3×10^-5mol/L）group.Actin cytoskeleton and β-catenin in HTM cells of the four groups were examined by immunofluorescence and Western blot analyses.RESULTS： In DEX group,there were reorganization of actin cytoskeleton and formation of cross linked actin networks（CLANs）,which were partially reversed in DEX and HA1077 group.DEX treatment also induced an increased expression of β-catenin,which was obviously reduced in DEX and HA1077 group.Meanwhile,the cultured HTM cells in HA1077 group had lower expression of β-catenin than that in the control group. CONCLUSION： Our results show that HA1077 can reverse the changes of actin organization and expression of β-catenin induced by DEX in cultured HTM cells,suggesting that HA1077 may play an important role in increasing outflow and reducing intraocular pressure.

Existence of Heme Oxygenase-carbon Monoxide-cyclic Guanosine Monophosphate Pathway in Human Trabecular Meshwork Cells In Vitro

To confirm the existence of heme oxygenase (HO)-carbon monoxide (CO)- cyclic guanosine monophosphate (cGMP) pathway in the cultured human trabecular meshwork cells (HTMCs) in vitro, and to evaluate the inductive role of hemin on this pathway, HTMCs of the third to fourth generation were cultured in vitro. Reverse transcripase-polymerase chain reaction (RT-PCR) was employed for detection of HO-1 and HO-2 mRNA. Immunohistochemical staining was used to detect HO-1 and HO-2 proteins. Hemin was added into the culture solution. The HO-1 mRNA levels were quantified by RT-PCR. The relative amount of carbon monoxide released into the media was measured with the quantifying carbon monoxide hemoglobin (HbCO) by spectrophotometry. Radioimmunoassay was used to determine changes of cGMP in HTMCs. The results showed that cultured cells had the specific characteristics of HTMCs. Both HO-1 and HO-2 genes were expressed in HTMCs, as well as HO-1 and HO-2 proteins in HTMCs. Hemin induced HO-1 mRNA, HbCO and cGMP in a dose-dependent manner. In conclusion, HO-CO-cGMP pathway exists in the cultured HTMCs and can be induced by hemin. Pharmacological stimulation of HO-CO-cGMP pathway may constitute a novel therapeutic approach to rescuing glaucoma.

Expression of CD44 in Cultured Human Trabecular Meshwork Cells

Purpose:To determine whether cultured human trabecular meshwork cells express CD44 and to discuss their possible relationship with primary open angle glaucoma.Methods:Human trabecular meshwork cells were cultured in DMEM/F12 media. Total RNAs from the cells were extracted with Trizol reagent. Messenger RNA expression of CD44 in human trabecular meshwork cells was examined by using reverse transcriptase-polymerase chain reaction ( RT-PCR ) analysis. Expression of CD44 was confirmed by Western-blotting and immunofluorescent microscopy. Effect of CD44-specific antisense oligonucleotide on adhesion of trabecular meshwork cells to hyaluronate was determined by MTT assay. Results:A single RT-PCR product whose size was 471bp was obtained. A band about 80kD was stained by Western-blot. Immunofluorescent examination of expression of CD44 on the cell surface was positive and reactions were mainly localized in cell membranes. Adhesion of trabecular meshwork cells to hyaluronate was inhibited by CD44-specific antisense oligonucleotide. Conclusions: Cultured human trabecular meshwork cells express CD44. CD44 may play a role in pathogenesis of primary open angle glaucoma. Eye Science 2004;20:52-56.

Aquaporin-1 Expressed in Cultured Human Trabecular Meshwork Cells

Objective:To determine if aquaporin-1 could be detected in cultures of human trabecularshwork cells. Methods: Using primers specific for aquaporin-1, reverse transcription combined withpolymerase chain reaction (RT-PCR) yielded a product and its size with total RNAprepared from the human trabecular meshwork cells. SDS-PAGE and immunoblottingwere also used in this study to detect the specific water channel.Results: The presence of this product and its size (298 base pairs) are consistent withthat of an aquaporin-1 message in these cells. A band of 28 kD in agreement with themolecular size of aquaporin-1 was showed in a film by immunoblotting.Conclusion: The presence of aquaporin-1 in human trabecular meshwork cells, thepredominant cell-type of the primary outflow region of the human eye, suggests that waterchannels may be involved in the movement of aqueous fluid out of the eye. In addition,the existence of aquaporin-1 on cultures of human trabecular meshwork cells provides anin vitro model to study the endogenous expression of aquaporin-1 and its possible role inthe regulation of aqueous outflow.

Inhibitory Effect of Tissue Transglutaminase (tTG) Antisense Oligodeoxynucleotides on tTG Expression in Cultured Bovine Trabecular Meshwork Cells

To study the effect of tTG fully phosphorothioated antisense oligodeoxynucleotides （tTG-ASDON） on tTG expression in cultured bovine trabecular meshwork cells （BTMCs） in vitro and explore a new treatment alternative for primary open angle glaucoma （POAG）, the ASDON1 and ASDON2 complementary to the protein codogram region of tTG were designed, synthesized and phosphorothioated according to the secondary structure of tTG. The ASDON1 and ASDON2 were embedded in Lipofectamine and transfected into BTMCs. The untreated group served as negative controls. The expression of tTG in the mRNA and protein level were measured by semi-quantitative RT-PCR and immunohistochemical technique-Supervision method respectively. Our results showed that both the mRNA and the protein of tTG with tTG-ASDON1 and tTCr-ASDON2 were significantly decreased as compared with that of the controls （P〈0.05）. On the other hand, no significant difference was found between the ASDON1 group and the ASDON2 group. It is concluded that the expression of tTG mRNA and protein in cultured BTMC are down-regulated by tTG- ASDON. As a result, tTG-ASDON may be used for the treatment of POAG through the inhibitory effect on the expression of tTG.

A Study of Toxicity of 5-Fluorouracil on Bovine Trabecular Meshwork Cells in Vitro

In order to explore whether the conventional use of 5 fluorouracil (5 Fu) had any toxic effects on trabecular meshwork cells, bovine trabecular meshwork cells were cultured in vitro and exposed to 5 Fu at different concentrations. The cellular morphology, ultrastructure, mortality and phagocytosis were studied under light microscopy, transmission electron microscopy and methods of Wright's stain. It was found that the toxic effects of 5 Fu on the cells were in a dose dependent mode. 1×10 -1 mg/ml of 5 Fu caused a large part of cells rounded up, while 1×10 -3 mg/ml of the drug only a rough appearance of the cell surface. Exposure to 1×10 -2 mg/ml of 5 Fu made mitochrone swollen and rough endoplasmic reticulum enlarged, with the cell mortality being 50.5 %. The latex microspheres engulfed in cytoplasm in cells receiving 1×10 -1 and 1×10 -2 mg/ml of 5 Fu were significantly decreased as compared with those in the control group ( P <0.01). It was concluded that the safe concentration of 5 Fu on bovine trabecular meshwork cells was 1×10 -3 mg/ml and the conventional dosage of 5 Fu in clinical practice would not cause injury to trabecular meshwork cells.

Effects of Nitric Oxide on Proliferation and Apoptosis of Cultured Bovine Trabecular Meshwork Cells

The effects of different doses of nitric oxide (NO) on the proliferation and apoptosis of the cultured bovine trabecular meshwork (TM) cells were studied. L arginine and N G nitro L arginine methyl (L NAME) were incubated with TM cells for 48 h. In the control group, no medicine was given. In the experimental groups, concentrations of L arginine and L NAME were 1×10 -7 mol/L, 1×10 -6 mol/L, 1×10 -5 mol/L, 1×10 -4 mol/L, 1×10 -3 mol/L and 1×10 -2 mol/L, respectively. NO 2 - in supernate, the proliferation and apoptosis of TM cells and mRNA expression of bcl 2 and bax were measured by Griess reagent, terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL), MTT assay and in situ hybridization,respectively. The results showed that L arginine with concentration ≥1×10 -4 mol/L could induce apoptosis of the TM cells and inhibit the proliferation of TM cells through increasing the NO levels, down regulating bcl 2 mRNA expression and up regulating bax mRNA expression; L NAME with concentration ≥1×10 -5 mol/L could induce the proliferation of the TM cells through suppressing the production of NO. It was concluded that NO in high level could induce apoptosis of the TM cells and suppress the proliferation of the TM cells.

Effects of Hydrostatic Pressure on Cultured Bovine Trabecular Meshwork Cells

In order to explore the effects of pressure on trabecular meshwork cells, bovine trabecular meshwork cells were cultured in vitro and subjected to different levels of hydrostatic pressure. The cellular morphology, ultrastructure and phagocytosis were studied with inverted phase-contrast microscopy, light microscopy and transmission electron microscopy, etc. It was found that the cells subjected to 2. 0 kPa or 2. 67 kPa for 48 h had no remarkable difference as compared with the controls in terms of parameters observed. Those under 4. 0 kPa for 24 h showed slight changes in structure and a mild decrease in phagocytic function. The damage appeared more severe if the pressure was higher or lasted longer. From the above we conclude that trabecular meshwork cells can only bear pressure below a certain level. They may be destroyed structurally or impaired functionally by pressure over this level.

Regulatory Effect of Dexamethasone on Aquaporin-1 Expression in Cultured Bovine Trabecular Meshwork Cells

To evaluate the effect of dexamethasone on the expression of aquaporin-1 （AQP-1） in cultured bovine trabeeular meshwork cells, bovine trabeeular meshwork cells were cultured in vitro and reproduced to the third and the fourth generation, then treated with dexamethasone at the concentrations of 5, 25, 50, 250μg/L respectively for 7 days. Immunohistochemical technique-supervision method was employed to measure, and image analysis system to analyze the expression of AQP-1 in normal cultured bovine trahecular meshwork cells and those treated with dexamethasone. In normal bovine trabeeular meshwork cells, the grayseale of AQP-1 positive staining was 167.94± 1.18, while it was 168.92±0.91, 176.72±1.80, 180. 64±1.31, 185.64±1.58 in cells treated with 5, 25, 50, 250μg/L concentrations of dexamethasone. When the concentration of dexamethasone was higher than 25 μg/L, the expression of AQP-1 was significantly inhibited （P〈0.05）. The regulation of AQP-1 expression by dexamethasone in cultured bovine trahecular meshwork cells in vitro may be one of causes that retard the aqueous outflow in glueoeorticoid-induced glaucoma.

Endothelial nitric oxide synthase deficiency influences normal cell cycle progression and apoptosis in trabecular meshwork cells

AIM： To clarify how the endothelial nitric oxide synthase （eNOS, NOS3） make effect on outflow facility through the trabecular meshwork （TM）. METHODS： Inhibition of NOS3 gene expression in human TM cells were conducted by three siRNAs. Then the mRNA and protein levels of NOS3 in siRNA-treated and negative control （NC） cells were determined, still were the collagen, type IV, alpha 1 （COL4A1） and fibronectin 1 by real-time PCR and Western blot analysis. In addition, NOS3 concentrations in culture supernatant fluids of TM cells were measured. Cell cycle and cell apoptosis analysis were performed using flow cytometry. RESULTS： The mRNA level of NOS3 was decreased by three different siRNA interference, similar results were obtained not only of the relative levels of NOS3 protein, but also the expression levels of COL4A1 and fibronectin 1. The number of cells in S phase was decreased, while contrary result was obtained in G2 phase. The number of apoptotic cells in siRNA-treated groups were significant increased compared to the NC samples. CONCLUSION： Abnormal NOS3 expression can make effects on the proteins levels of extracellular matrix component （e.g. fibronectin 1 and COL4A1）. Reduced NOS3 restrains the TM cell cycle progression at the G2/ M-phase transition and induced cell apoptosis.

Effect of Transforming Growth Factor-β_2 on Phagocytosis in Cultured Bovine Trabecular Meshwork Cells

The effect of transforming growth factor β 2 (TGF β 2) on phagocytosis in bovine trabecular meshwork cells in vitro was investigated. After the cultured bovine trabecular meshwork cells were treated with 0 ng/ml, 0.32 ng/ml, 1 ng/ml, 3.2 ng/ml TGF β 2 for 24 h, latex beads were added into the incubation medium, and the numbers of the latex beads in 20 adjacent cells were counted under a microscope 24 h later, after treatment with Wright's stain. Our results showed that the average numbers of the latex beads in the trabecular meshwork cells treated with TGF β 2 of different concentrations were 53.1±1.7 beads/cell, 56.4±2.9 beads/cell and 77.9±6.5 beads/cell respectinvely, in comparison with 45.5±3.3 beads/cell of the control group. TGF β 2 significantly increased the number of the latex beads phagocytosed by cultured bovine trabecular meshwork cells in a dose dependent manner. TGF β 2 could promote the phagocytosis of bovine trabecular meshwork cells in vitro . It may be involved in the cellularity decrease of the trabecular meshwork in the patients of primary open angle glaucoma through promoting the phagocytosis of trabecular meshwork cells.

A Study of Toxic Effect of Mitomycin C on Cultured Bovine Trabecular Meshwork Cells

Purpose:To explore the toxicity of Mitomycin C(MMC)on trabecular meshwork cells.Methods:Bovine trabecular meshwork cells were cultured in vitro and exposed to MMC of different concentrations,The cellular morphology,ultrastructure,mortality and phagocytosis was studied with light microscopy,transmission electron microscopy and methods of Wright's stain ,etc.Results:It was found that the toxic effect of MMC on the cells was in a dose-dependent mode,1×10^-2and1×10^-3mg/mlofMMC caused a large part of cells dead,1×10^-4and1×10^-5mg/mlof the drug had remarkable killing effect on the cells,1×10^-6mg/ml of MMC had still a mild toxicity,while1×10^-7mg/ml of MMChad not any influence on cellular morphology,mortality,and phagocytosis,etc.The safe concentration o n bovine trabecular meshwork cells was1×10^7mg/ml and the LD50 was between1×10^-3and1×10^-4mg/ml.Conclusions:Refering to previous data,we conclude that conventional clinical-application of MMC might do harm to trabecular meshwork cells.Eye Science2000;16:38-42.

Identification, quantification and agerelated changes of human trabecular meshwork stem cells

Background:Loss of cells in the human trabecular meshwork(TM)has been reported with ageing and in glaucoma.This study aims to identify,quantify and determine the age-related changes of human TM stem cells(TMSCs).Methods:Isolation of TM cells/paraffin sectioning was carried out using human corneoscleral rings and whole globes.The TM cells/sections were immunostained for the stem cell markers ATP-binding cassette protein G2(ABCG2),nerve growth factor receptor p75 and AnkyrinG(AnkG).Images were acquired using Leica SP8 confocal microscope.The isolated cells were analyzed for two parameters-ABCG2 expression and nucleus to cytoplasmic ratio(N/C ratio).The total number of TM cells and those positive for ABCG2 and p75 in each section were quantified.Spearman rank order correlation was used to determine the association between age and the cell counts.Results:The TMSCs were identified based on two parameters-high ABCG2 expression and high N/C ratio>0.7.These stem cells were also positive for p75 and AnkG.The TMSC content based on the two parameters was 21.0±1.4%in<30 years age group,12.6±6.6%in 30–60 years and 4.0±3.5%in>60 years.The stem cells with high ABCG2 and p75 expression were restricted to the Schwalbe’s line region of the TM.A significant correlation was observed between the reduction in TMSC content and TM cell count during ageing.Conclusion:The human TMSCs were identified and quantified based on two parameter analysis.This study established a significant association between age-related reduction in TMSC content and TM cell loss.

Expression profile analysis to identify potential gene changes induced by dexamethasone in the trabecular meshwork

AIM:To investigate potential gene changes in trabecular meshwork(TM)induced by dexamethasone(DEX)in steroidinduced glaucoma(SIG).METHODS:The expression data of 24 cases from a public functional genomics data were sorted to identify the mechanisms of action of DEX on the TM.The relationships of the differentially expressed genes(DEGs)were enriched using Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis.In addition,the hub genes were screened by the Search Tool for the Retrieval of Interacting Genes Database(STRING)and Cytoscape tools.Finally,human TM cells(HTMCs)were treated with DEX to preliminarily explore the function of hub genes.RESULTS:Totally 47 DEGs,including 21 downregulated and 26 upregulated genes were identified.The primary enriched results of the DEGs consisted of inflammatory response,extracellular matrix(ECM),negative regulation of cell proliferation,TNF signalling pathway and the regulation of tr yptophan channels by inflammator y mediators.Subsequently,pro-melanin-enriched hormone(PMCH)and Bradykinin B1 receptor(BDKRB1)were screened as hub genes.It is verified in GSE37474 data set.Western blot and quantitative real-time polymerase chain reaction(q PCR)results showed that protein and RNA expression levels of BDKRB1 were significantly decreased after DEX treatment,while PMCH was not significantly changed.CONCLUSION:BDKRB1 may be a key gene involved in SIG onset,providing a suitable therapeutic target for improving the prognosis of SIG patients.