Recombinant Schistosoma japonicum cystatin alleviates acute liver injury in mice by inhibiting endoplasmic reticulum stress,inflammation and hepatocyte apoptosis
Objective To investigate the protective effect of recombinant Schistosoma japonicum cystatin(rSj-Cys)against acute liver injury induced by lipopolysaccharide(LPS)and D-GalN in mice.Methods Adult male C57BL/6J mice with or without LPS/D-GaIN-induced acute liver injury were given intraperitoneal injections of rSj-Cys or PBS 30 min after modeling(n=18),and serum and liver tissues samples were collected from 8 mice in each group 6 h after modeling.The survival of the remaining 10 mice in each group within 24 h was observed.Serum levels of ALT,AST,TNF-α and IL-6 of the mice were measured,and liver pathologies was observed with HE staining.The hepatic expressions of macrophage marker CD68,Bax,Bcl-2 and endoplasmic reticulum stress(ERS)-related proteins were detected using immunohistochemistry or immunoblotting,and TUNEL staining was used to detect hepatocyte apoptosis.Results The survival rates of PBS-and rSj-Cys-treated mouse models of acute liver injury were 30%and 80%at 12 h and were 10%and 60%at 24 h after modeling,respectively;no death occurred in the two control groups within 24 h.The mouse models showed significantly increased serum levels of AST,ALT,IL-6 and TNF-α and serious liver pathologies with increased hepatic expressions of CD68 and Bax,lowered expression of Bcl-2,increased hepatocyte apoptosis,and up-regulated expressions of ERS-related signaling pathway proteins GRP78,CHOP and NF-κB p-p65.Treatment of the mouse models significantly lowered the levels of AST,ALT,IL-6 and TNF-α,alleviated liver pathologies,reduced hepatic expressions of CD68,Bax,GRP78,CHOP and NF-κB p-p65,and enhanced the expression of Bcl-2.In the normal control mice,rSj-Cys injection did not produce any significant changes in these parameters compared with PBS.Conclusion rSj-Cys alleviates LPS/D-GalN-induced acute liver injury in mice by suppressing ERS,attenuating inflammation and inhibiting hepatocyte apoptosis.