Cirrhosis in rats does not resolve in the long-term after induction by thioacetamide model

Introductions: Hepatic cirrhosis is a final common pathway of all chronic liver diseases, characterized by deposit of fibrillar collagen and liver failure. Materials and Methods: In this experiment, hepatic cirrhosis was induced in 15 female Wistar rats by a 14-week period, with thioacetamide solution in a 200 mg/kg dosage, via intraperitoneal. Animals were submitted to liver biopsy, and euthanized after a 80-day post-induction period. Serum biochemical analysis was performed, in addition to histopathology by H.E., Picrosirius, Alcian Blue and P.A.S. stainings, following analysis of histological activity index and staging of fibrosis. Morphometric analysis of collagen on Picrosirius slides was also performed. Results: Mortality during experimental period was low (13.33%), and after 80-day period, liver function improved, cellular changes did not altered, and deposition of acidic mucopolysaccharides and glycogen were increased. Liver histological activity did not change significantly (7.25 ± 1.30 to 6.41 ± 1.32), but staging of fibrosis was altered (3.91 ± 0.76 to 4.70 ± 1.11). Interlobular collagen showed a significant decrease (5.14 ± 2.00 to 4.00 ± 1.20), while intralobular collagen was increased (0.23 ± 0.06 to 0.36 ± 0.08). Conclusions: These findings characterize thioacetamide as a safe experimental model for induction cirrhosis, which may be used for future therapy studies.(AU)

Antifibrotic effects of magnesium lithospermate B on hepatic stellate cells and thioacetamide-induced cirrhotic rats

Magnesium lithospermate B (MLB) is one of the major active components of Salvia miltiorrhizae. The anti-oxidative effects of Salvia miltiorrhizae have been previously reported. The aim of this study was to investigate the effect of purified MLB on hepatic fibrosis in rats and on the fibrogenic responses in hepatic stellate cells (HSCs). Hepatic fibrosis was induced in rats by intraperitoneal thioacetamide (TAA) injections over a period of 8 or 12 weeks. MLB was orally administered daily by gavage tube. Serum AST and ALT levels in TAA + MLB group were significantly lower than those in TAA only group at week 8. Hepatic fibrosis was significantly attenuated in TAA + MLB group than in TAA only group at week 8 or 12. Activation of HSCs was also decreased in TAA + MLB group as compared to TAA only group. Hepatic mRNA expression of alpha-smooth muscle actin (alpha-SMA), TGF-beta1, and collagen alpha1(I) was significantly decreased in TAA + MLB group as compared to TAA only group. Incubation with HSCs and MLB (> or =100 microM) for up to 48 h showed no cytotoxicity. MLB suppressed PDGF-induced HSC proliferation. MLB inhibited NF-kappaB transcriptional activation and monocyte chemotactic protein 1 (MCP-1) production in HSCs. MLB strongly suppressed H2O2-induced reactive oxygen species (ROS) generation in HSCs, and MLB inhibited type I collagen secretion in HSCs. We concluded that MLB has potent antifibrotic effect in TAA-treated cirrhotic rats, and inhibits fibrogenic responses in HSCs. These data suggest that MLB has potential as a novel therapy for hepatic fibrosis.

Changes in expression of cell cycle regulators after G1 progression upon repetitive thioacetamide treatment in rat liver

Repetitive low dose thioacetamide (TA) treatment of hepatocytes was found to induce cells in G2 arrest. In the present study, an attempt was made to investigate alterations in expression of cell cycle regulators after G1 progression in the same repetitive low dose TA treated hepatocytes system and to define the determinators involved in G2 arrest. TA was daily administered intraperitoneally, with a dose of 50 mg/kg for 7 days. Expression levels of cyclin E and CDK2 were similar, increased at day 1 and reached a peak at day 2. And they recycled from day 3 reaching a second peak at day 5. Expression level of cyclin A was similar to p27(Kip1) and p57(Kip2) but not to CDK2 and increased to a peak level at day 2. Expression levels of cyclin B1 and cdc2 were similar although the cyclin B1 level was generally low, decreased from day 1 to basal levels at day 3 and persisted at a low level till day 7. The expression level of cyclin G1 was similar to p53 that peaked at day 3 and again at day 6 elevated over basal level. BrdU-labeled hepatocytic nuclei increased from 12 h, reached a peak at day 2, then decreased, and were not detectable from day 6. The number of PCNA-labeled nuclei increased immediately, peaked at day 2, and maintained till day 7. These results suggest that G2 arrest induced by repeated TA treatment might be p53-dependent, via activation of cyclin G1, rather than inhibition of cyclin B1- cdc2 complex, and inhibitors holding S phase progression might be p27(Kip1) and p57(Kip2).