ABSTRACT
Objective To study the promoting effects and mechanisms of interleukin-22 on liver regeneration in GCl4-induced liver fibrosis mice after partial hepatectomy.Methods One hundred and fortyfour C57/BL6 mice were randomly divided into four groups:PHX group,CCl4 group,CCl4 + PHX group,and CCl4 + IL22 + PHX group.The blood samples were taken to measure serum ALT and AST levels.ALT /AST was calculated to observe the liver injury at 3 h,6 h,12 h,24 h,48 h and 72 h after hepatectomy.The liver tissue specimens were collected at each time point after hepatectomy.We measured the hepatic lobe to calculate the liver weight ratio and conducted pathological examinations to observe the degree of fibrosis and pathological changes at each time point.The positive expression of proliferating cell nuclear antigen (PCNA) in liver tissue was tested by immunohistochemistry.The level of CyclinD1 and STAT3 (Signal transducer and activator of transcription 3) signaling pathway was detected by Western blot.Results (1) Compared with CCl4 + PHX group,the ALT/AST ratio of CCl4 + IL22 + PHX group was significantly higher at 24 h,48 h and 72 h,and the level of ALB of CCl4 + IL22 + PHX group was obviously increased at 48 h and 72 h (P ＜ 0.05).(2) The liver regeneration was significantly increased in CCl4 + IL22 + PHX group.Compared with CCl4 + PHX group (2.08 ± 0.16,2.77 ± 0.07,2.97 ± 0.14),the liver weight ratio of CCl4 + IL22 + PHX group(2.34 ± 0.07,3.23 ± 0.09,3.55 ± 0.09) dramatically increased at 24 h,48 h and 72 h.Moreover,the pathological sections displayed that the disease was alleviated (P ＜ 0.05).(3) Immunohistochemical assay and western blot revealed that compared with other three groups,the level of PCNA,STAT3 and Cyclin D1 was significantly lower in the CCl4 + PHX group.However,the level of PCNA,STAT3 and Cyclin D1 apparently increased in CCl4 + IL22 + PHX group at 24 h,48 h and 72 h (P ＜ 0.05).Conclusion Interleukin-22 may significantly promote liver regeneration and reduce liver pathological injury in liver fibrosis mice induced by administration of CCl4 after hepatectomy,which plays a positive role in the recovery of liver function.