Experimental Study On The Effect Of Vitamin A Deficiency On Liver Injury In Immune-induced Hepatitis

Objective: This study established a mouse model of immune hepatitis combined with vitamin A deficiency,and examined liver inflammation and fibrosis related markers to explore the role of vitamin A deficiency in the pathogenesis of immune hepatitis.By administering retinoic acid(RA)and retinol palmitate(RP)treatment,we observe its regulation in hepatic inflammation and fibrosis,and explore possible mechanisms of this action.Methods:(1)4 weeks male C57B6 mouse(n=112)have been used for VAD mouse model.We subdivided them into 14 groups: 8 weeks VAS and VAD,10 weeks VAS and VAD,12 weeks VAS and VAD,14 weeks VAS and VAD,16 weeks VAS and VAD,20 weeks VAS and VAD and 24 weeks VAS and VAD(n=8).Then we measure the vitamin A level in each group.(2)We used 50 pregnancy C57B6 mouse to establish VAS-con A and VAD-con A mouse model.We subdivided 64 newborn male mice into 8 groups: VAS-SHAM,VAS-con A,VAS-con A+RA,VAS-con A+RP,VAD,VAD-con A,VAD-con A+RA and VAD-con A+RP.We collected plasma and liver samples to measure vitamin A level and liver damage markers in plasma and vitamin A level and expression of inflammatory genes iNOS,HO-1 and PAI1 in liver.By the usage of Western Blot,we measure the expression of JNK and MAPK in liver.(3)In chronic VAS-con A and VAD-con A mouse with vitamin A therapy models,we subdivided 64 newborn male mice into 8 groups as part 2.We measure expression of fibrosis genes a SMA and Col1a1 in liver.By the usage of Western Blot,we measure the expression of collagen in liver.Results:(1)There was no significant difference in body weight between VAD and VAS mice(P>0.05).In HE staining,VAD-conA group shown more necrosis areas and numbers of inflammatory cells than VAS-conA group in liver.The level of ALT and AST is higher in VAD-con A than VAS-con A(P<0.05).The expression of iNOS and HO-1 is higher in VAD-con A than VAS-con A(P<0.05).Compared with VAS-conA group,the expression level of the above indicators in VAD-conA group was significantly higher(P<0.05).(2)Retinoic acid treatment can improve the survival rate of immune hepatitis mice.Compared with pre-treatment,in the VAD-conA and VAS-conA mice,pathologically visible necrotic areas and inflammatory cells were reduced after RA treatment,plasma ALT and AST levels were decreased(P<0.05),and RP treatment did not change significantly.(3)RA and RP treatment can improve the survival rate of mice with chronic immune hepatitis.Compared with pre-treatment,pathologically visible necrotic areas and inflammatory cells of liver tissues in mice with VAD combined with chronic immune hepatitis after RA treatment.Compared with pre-treatment,after treatment with RA or RP in mice with VAD and chronic hepatitis,the expression levels of a-SMA,Col1a1,and collagen decreased(P<0.05),but the effect of RA was more significant.Conclusions:(1)In the VAD model,there was a linear inverse relationship between vitamin A levels and time in the liver of mice.In immunological hepatitis mice,whether or not there is vitamin A deficiency,the levels of ALT and AST in blood plasma increased,liver pathology showed hepatocyte necrosis and lymphocyte infiltration,and the expression of iNOS and HO-1 in liver tissue increased.(2)VAD can aggravate hepatic injury in immune hepatitis.(3)Retinoic acid attenuates hepatic injury in immunological hepatitis mice through JNK-MAPK pathway.(4)Retinoic acid alleviates con A-induced hepatic fibrosis by reducing expression of Col1a1 and a-SMA.