Published online May 14, 2015. doi: 10.3748/wjg.v21.i18.5465
Peer-review started: November 10, 2014
First decision: December 11, 2014
Revised: December 29, 2014
Accepted: March 12, 2015
Article in press: March 12, 2015
Published online: May 14, 2015
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 survival rates 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 day 2 (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-α and 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.
Core tip: Our research confirmed that phycocyanobilin (PCB) plays a hepatoprotective role on carbon tetrachloride-induced acute liver injury mice. It was shown that PCB has a strongly anti-inflammatory effect when the liver suffered oxidative damage. The results showed that PCB could accelerate liver regeneration, reduce apoptosis and necrosis of the hepatocytes by regulating the expression of hepatocyte growth factor, transforming growth factor (TGF)-α, TGF-β, tumor necrosis factor-α and interleukin-6. In addition, PCB could significantly improve the survival probability of the acute liver injury mice.