Pien Tze Huang Gan Bao attenuates carbon tetrachloride-induced hepatocyte apoptosis in rats, associated with suppression of p53 activation and oxidative stress

Pien Tze Huang Gan Bao (PZH-GB), a traditional Chinese medicine, has been used for thousands of years as a protective remedy effective against liver injury induced by excessive alcohol and smoking. The present study aimed to evaluate the protective effects and potential mechanisms of PZH-GB against carbon tetrachloride (CCl(4))-induced hepatic injury. Rats were pre-treated with silymarin (50 mg/kg) or different doses of PZH-GB (150, 300 or 600 mg/kg) orally administered for 7 days. At the end of treatment, the rats were intraperitoneally injected with CCl(4), or control rats received a corn oil injection. The lactate dehydrogenase (LDH) levels in serum were evaluated. Apoptosis was assessed via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. p53, B-cell lymphoma 2 (Bcl-2), B cell-lymphoma 2-associated X protein (Bax), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and cytochrome P450 family 2 subfamily E member 1 (CYP2E1) were measured by reverse transcription-quantitative polymerase chain reaction and western blotting. The activity of caspase-9 and caspase-3 were measured by a colorimetric assay. The results indicated that silymarin and PZH-GB prevented CCl(4)-induced serum LDH elevations, and CCl(4) induced high levels of LDH. Compared with the CCl(4) group, silymarin and PZH-GB treatment significantly decreased LDH levels. Histopathological results revealed that silymarin and PZH-GB ameliorated the CCl(4)-induced liver histological alterations. The TUNEL results showed that compared with the control group, CCl(4) induced liver cell apoptosis, while silymarin and PZH-GB treatment inhibited apoptosis and the TUNEL-positive cells. The elevated expression of Bax, p53, iNOS, COX-2 and CYP2E1 were reduced by silymarin or PZH-GB pretreatment, whereas reduced Bcl-2 expression levels were increased. CCl(4) increased the activity of caspase-9 and −3 by 6.86- and 7.42-fold, respectively; however, silymarin and PZH-GB ameliorated this effect. In conclusion, silymarin and PZH-GB treatment prevented the deleterious effects on liver functions by attenuation of oxidative stress, inflammation and mitochondrial apoptosis via the p53 signaling pathway.