Glycyrrhizic acid attenuates CCl 4 -induced hepatocyte apoptosis in rats via a p53-mediated pathway

Abstract

AIM: To investigate the effect of glycyrrhizic acid (GA) on carbon tetrachloride (CCl4)-induced hepatocyte apo-ptosis in rats via a p53-dependent mitochondrial path-way. METHODS: Forty-five male Sprague-Dawley rats were randomly and equally divided into three groups, the control group, the CCl4 group, and the GA treatment group. To induce liver fibrosis in this model, rats were given a subcutaneous injection of a 40% solution of CCl4 in olive oil at a dose of 0.3 mL/100 g body weight biweekly for 8 wk, while controls received the same isovolumetric dose of olive oil by hypodermic injection, with an initial double-dose injection. In the GA group,rats were also treated with a 40% solution of CCl4 plus 0.2% GA solution in double distilled water by the intraperitoneal injection of 3 mL per rat three times a week from the first week following previously published methods, with modifications. Controls were given the same isovolumetric dose of double distilled water. Liver function parameters, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were de-termined. Pathologic changes in the liver were detected by hematoxylin and eosin staining. Collagen fibers were evaluated by Sirius red staining. Hepatocyte apoptosis was investigated using the terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick end labeling (TUNEL) assay and the cleaved caspase-3 immunohistochemistry assay. The expression levels of p53 and apoptosis-related proteins were evaluated by immunohistochemistry or Western blotting analysis. RESULTS: After 8 wk of treatment, GA significantly re-duced serum activity of ALT (from 526.7 ± 57.2 to 342 ± 44.8, P<0.05) and AST (from 640 ± 33.7 to 462.8 ± 30.6, P<0.05), attenuated the changes in liver his-topathology and reduced the staging score (from 3.53 ± 0.74 to 3.00 ± 0.76, P<0.05) in CCl4 -treated rats. GA markedly reduced the positive area of Sirius red and the ratio of the hepatic fibrotic region (from 7.87% ± 0.66% to 3.68% ± 0.32%, P<0.