Phycocyanobilin accelerates liver regeneration and reduces mortality rate in carbon tetrachloride-induced liver injury mice

AIM: To investigate the hepatoprotective effects of phycocyanobilin(PCB) in reducing hepatic injury and accelerating hepatocyte proliferation following carbon tetrachloride(CCl4) treatment.METHODS: C57BL/6 mice were orally administered PCB 100 mg/kg for 4 d after CCl4 injection, and then the serum and liver tissue of the mice were collected at days 1, 2, 3, 5 and 7 after CCl4 treatment. A series of evaluations were performed to identify the curative effects on liver injury and recovery. Aspartate aminotransferase(AST), alanine aminotransferase(ALT), albumin and superoxide dismutase(SOD) were detected to indirectly assess the anti-inflammatory effects of PCB. Meanwhile, we detected the expressions of hepatocyte growth factor, transforming growth factor alpha(TGF-α), TGF-β, tumor necrosis factor-alpha(TNF-α) and interleukin-6(IL-6), the factors which are associated with inflammation and liver regeneration. The protein expressions of proliferating cell nuclear antigen(PCNA), TNF-α and cytochrome C were detected by western blot. Furthermore, the survivalrates were analyzed of mice which were administered a lethal dose of CCl4(2.6 mg/kg)with or without PCB.RESULTS:In our research,PCB showed a strongly anti-inflammatory effect on CCl4-induced liver injury in mice.The ALT was significantly decreased after CCl4 treatment from day 1(P<0.01)and the AST was significantly decreased from day 2(P<0.001).Both albumin and liver SOD were increased from day2(P<0.001 and P<0.01),but serum SOD levels did not show a significant increase(P>0.05).PCB protected the structure of liver from the injury by CCl4.TUNEL assay showed that PCB dramatically reduced the number of apoptotic cells after CCl4 treatment compared to the control(101.0±25.4 vs 25.7±6.4,P<0.01).The result of western blotting showed that PCB could increase PCNA expression,decrease TNF-αand cytochrome C expression.Furthermore,data shows that PCB could improve the survival rate of acute liver failure(ALF)mice which were injected with a lethal dose of CCl4(60.0%vs 20.0%).CONCLUSION:Our study indicated that PCB could be an ideal candidate for reversing acute liver injury or ALF.