Protective Effect of Glycyrrhiza glabra Extract against tert-butyl hydroperoxide(t-BHP)-induced Hepatotoxicity in Primary Cultured Hepatocytes of Jian Carp(Cyprinus carpio var. jian)
Abstract：Fish "liver and gall syndrome", characterized by liver (hepatocyte) injury, has become more and more serious in China aquaculture, however no effective methods have been found for the prevention and treatment of this disease. The present study aimed to develop an in vitro model of hepatotoxicity using tert-butyl hydroperoxide (t-BHP) as hepatotoxicant and evaluate the protective effects of Glycyrrhiza glabra extract against t-BHP induced hepatotoxicity in Jian carp (Cyprinus carpio var. jian). Exposure of the hepatocytes to 1 mmol/L t-BHP for 2 h significantly elevated the levels of glutamate oxalate transaminase (GOT), glutamate pyruvate transaminase (GPT), lactate dehydrogenase (LDH) and malondialdehyde (MDA), and reduced the cell viability and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Three concentrations of G. glabra extract (0.1, 0.2 and 0.4 mg/mL) were added to the primary hepatocytes before (pre-treatment), after (post-treatment) and both before and after (pre- and post-treatment) the exposure of the hepatocytes to t-BHP. Results showed that pre- and post-treatment of the hepatocytes with G. glabra extract at 0.1, 0.2 and 0.4 mg/mL suppressed the elevations of LDH, GOT, GPT and MDA, and reversed the reduced activities of GSH-Px and SOD. Pre-treatment of the hepatocytes with 0.4 mg/mL G. glabra extract reduced the increased levels of GPT, GOT, LDH and MDA, and increased the reduced GSH-Px activity. Post-treatment didn't show significant effects expect for the enhanced GSH-Px activity in the cells post-treated with 0.4 mg/mL G. glabra extract. The significantly increased cell viabilities were observed when the cells were pre-treated, post-treated and pre- and post-treated with 0.2 mg/mL and 0.4 mg/mL G. glabra extract. The results also showed that the timing of G. glabra extract treatment substantially influenced the protective efficacy of the extract, the pre- and post-treatment of the hepatocytes with G. glabra extract was better than that of the other two treatment regimes. It can be concluded that G. glabra extract exhibited protective effect against t-BHP-induced hepatotoxicity in fish. Further in vivo studies are needed to provide more evidence for using G. glabra as a hepatoprotective agent for the prevention and treatment of fish "liver and gall syndrome".
