Ameliorative effects of tannic acid on carbon tetrachloride-induced liver fibrosis in vivo and in vitro.

We investigated the ameliorative effects and potential mechanisms of tannic acid (TA) in carbon tetrachloride (CCl4)-intoxicated mice and hepatic stellate cells (HSCs). Liver fibrosis was observed in CCl4 (800 ml/kg)-induced mice, and high viability was observed in CCl4 (10 mM)-intoxicated HSCs. Pre-treatment of mice with TA (25 or 50 g/kg/day) significantly ameliorated hepatic morphology and coefficient values and reduced the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), the concentrations of malondialdehyde (MDA) and serum levels of endothelin-1 (ET-1). In addition, TA increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and endothelial nitric oxide synthase (eNOS) and the serum level of NO. Moreover, TA reduced the expression of angiotensin II receptor-1 (ATR-1), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), transforming growth factor-ß (TGF-ß), caspase-3, c-fos, c-jun, the ratio of Bax/bcl-2, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TA increased matrix metal proteinase-9 (MMP-9), matrix metalloproteinase-1 (MMP-1). Furthermore, TA (0.01 µM, 0.1 µM or 1 µM) decreased the TIMP-1/MMP-1 ratio and reduced the viability of HSCs. These results indicated that TA exerts significant liver-protective effects in mice with CCl4-induced liver fibrosis. The potential mechanism may rely on the inhibition of collagen accumulation, oxidative stress, inflammation and apoptosis.

[Construction and expression of prokaryotic expression plasmids of Pneumocystis carinii p55 antigen gene fragment].

OBJECTIVE: To construct prokaryotic recombinant expression plasmid carrying Pneumocystis carinii Mr 55 000 antigen (p55) gene fragment and express the recombinant protein. METHODS: P. carinii pneumonia (PcP) rat models were established by subcutaneous injection of dexamethasone for 14 weeks. Total RNA was extracted from lung of P. carinii rat and p55 antigen gene fragment was cloned by RT-PCR, which was identified by sequencing. The 690 bp fragment was cloned to pGEX-4T-1, the recombinant plasmid was screened and identified by restriction analysis and PCR. The recombinant plasmid was finally induced with IPTG to express a new fusion protein, and the products were analyzed by SDS-PAGE and Western blot. RESULTS: A fragment of 690 bp was obtained by RT-PCR. The recombinant pGEX-4T-1/690 was constructed. SDS-PAGE revealed that the molecular weight of the recombinant protein was approximately Mr 62,000, the maximum amount of the fusion protein produced was 11.6% of the total protein. The recombinant protein can be recognized by GST antibody and by the sera from P. carinii infected rats using Western blotting. CONCLUSION: Prokaryotic expression plasmid pGEX-4T-1/690 has been constructed and the recombinant fusion protein shows antigenicity.