Differentially expressed genes identified by microarray analysis following oxymatrine treatment of hepatic stellate cell

AIM: To investigate the effects of oxymatrine on the gene expression profile of hepatic stellate cell (HSC) and provide novel insights into the mechanism of oxymatrine against hepatic fibrosis. Methods: HSC was isolated from normal SD by in situ perfusion of collagenase and pronase and density Nycodenz gradient centrifugation. MTT colorimetry was used to study the effect of oxymatrine on the proliferation of HSC. Total RNA and mRNA of quiescent HSC, culture-activated HSC and oxymatrine treated HSC were extracted. Effect of oxymatrine on HSC gene expression profile was detected by oligonucleotide microarray analysis with Affymetrix gene chip rat U230A. Differentially expressed genes were annotated with Gene Ontology (GO) and analyzed with Kyoto encyclopedia of genes and genomes (KEGG) pathway using the Database for Annotation, Visualization and Integrated Discovery. Results: Oxymatrine could inhibit the proliferation of HSC in a dose-dependent manner. A total of 4641 differentially expressed genes were identified by cDNA chip between activated and quiescent HSC, among which 2702 genes were upregulated, and 1939 genes were down-regulated in activated HSC. cDNA microarray uncovered downregulation of 56 genes in response to oxymatrine, the representative genes including alpha 2 type I procollagen, alpha-1 type I collagen, tissue inhibitor of metalloproteinase 1, interleukin 1 beta, early growth response 1, chemokine ligand 2, chemokine ligand 1, CTGF, TGFβ1. The most enriched GO terms included response to wounding, inflammatory response, cell migration, cell motility, wound healing, TGFβ receptor signaling pathway. KEGG pathway analysis revealed that oxymatrine affected the ECM-receptor interaction, focal adhesion, cytokine-cytokine recaptor interaction, TGFβ signaling pathway, MAPK signaling pathway. There were 37 genes upregulated significantly following oxymatrine treatment. The most enriched GO terms included oxidation reduction, negative regulation of lipoprotein oxidation, regulation of lipoprotein oxidation, steroid metabolic process, regulation of lipase activity. Six genes were confirmed with QPCR, consistent with microarray. Conclusion: The mechanism of oxymatrine in inhibiting liver fibrogenesis is associated with multi-genes and multi-pathways regulation.