Effect Of Calpain 2 And Autophagy Related Gene 7 On Non-alcoholic Fatty Liver Disease

Objective:To investigate expression and significance of ATG7 and Calpain 2 in nonalcoholic fatty liver disease.Methods:(1) Thirty male Sprage-Dawey rats were randomly divided into basic diet control group (Group C),while control rats fed with normal food and high-fat diet group(Group F),in vivo model of NAFLD was established by high fat diet(87.5% standard diet,10% lard oil,2% cholesterin and 0.5% bile salt),NAFLD group was divided into 4 subgroups(4, 8, 12, 16weeks)(n=6 in each group).(2)The parameters in each group were observed dynamically:①Blood samples were collected to check serum free fatty acid( FFA),alanine aminotransferase (ALT),as partate transaminase (AST);②Steatosis of liver tissues were valued by HE staining and electron microscopy;③The mRNA expression of Calpain 2 and ATG7 were detected by real-time quantitative RT-PCR(qRT-PCR) ;④Western blots at protein level of Calpain 2 and ATG7 in rat liver respectively.Results:①Compared with the control group, the serum content of ALT, AST, FFA in NAFLD rats was increased with different degree,and significantly increased at 16th week(165.95±7.24 U/L,249.52±4.20 U/L,0.83±0.05mmol/L,respectively P < 0.01).②HE staining implicated that the degree of hepatic steatosis increased with the time of high fat diet fedding:fatty degeneration at 4w, mild fatty liver at 8W, moderate to severe fatty liver at 12 W in Group F,hepatic fibrosis at 16W;③real-time PCR:The relative mRNA expression of Calpain 2 at mRNA level increased after HFD and reached its peak at 16th week,and was 9.83±0.85 fold as the control group ( P <0.01).While the relative expression of ATG7 began to decrease at 4th week(0.82±0.02),and reached its lowest level at 16th week (0.20±0.03 ,P < 0.01)according to the control group.④As with the protein level of Calpain 2 began to increase at 4th week(2.32±0.45),and was 9.87±1.20 fold as the control group ( P <0.01).While the expression of ATG7 at protein level was down regulated with progress of steatosis, and was significantly at 16th week(0.18±0.05,respectively P<0.01).Conclusion:1. Autophagy involved in the NAFLD the whole formation process, in its forming process has played an important role;2. In NAFLD rat liver issues model of NASH stage, ATG7 and Calpain 2 change the most obvious, show autophagy may be involved in the NASH occurs.