Hepatoprotective effects of cathepsin B inhibitor on acute hepatic failure induced by lipopolysaccharide/D-galactosamine in mice

BACKGROUND:Increasing evidence suggests that the inactivation of cathepsin B attenuates hepatocyte apoptosis and liver damage.This study aimed to investigate the protective effects of a cathepsin B inhibitor(CA-074me) on lipopolysaccharide(LPS)/D-galactosamine(D-GalN)-induced acute hepatic failure(AHF) in mice.METHODS:Mice were intraperitoneally injected with a combination of LPS/D-GalN to induce AHF with or without CA-074me pretreatment.The cumulative survival rates were calculated 48 hours after the induction of AHF.As well as changes in biochemical indicators and liver histology,hepatocyte apoptosis was assessed using a TUNEL method.Serum tumor necrosis factor-α(TNF-α) production,caspase-3,caspase-8,and caspase-9 activity was evaluated.Cytosolic cytochrome c and Bcl-2 expression were measured by Western blotting.RESULTS:The marked elevation in serum aminotransferase activity and prothrombin time found in LPS/D-GalN-treated mice was significantly improved by pretreatment with CA074me.The efficacy of CA-074me was also confirmed by histological analysis and TUNEL assay.The survival rate significantly improved in LPS/D-GalN-induced mice given CA-074me compared with untreated mice.LPS/D-GalNinduced caspase-3 and caspase-9 activation was remarkably suppressed by CA-074me.However,the increased levels of serum TNF-α and elevated caspase-8 activity in AHF mice were not significantly reduced by CA-074me.Moreover,CA074me sharply reduced the increased expression of cytosolic cytochrome c and markedly augmented Bcl-2 expression.CONCLUSION:These results suggest that CA-074me has a protective effect in acute hepatic failure induced by LPS/D-GalN.

Role of cathepsin B-mediated apoptosis in fulminant hepatic failure in mice

AIM: To investigate the pathogenic role of cathepsin B and the protective effect of a cathepsin B inhibitor (CA074Me) in fulminant hepatic failure in mice. METHODS: LPS/D-Gal N was injected into mice of the model group to induce fulminant hepatic failure; the protected group was administered CA-074me for 30 min before LPS/D-Gal N treatment; the normal group was given isochoric physiologic saline. Liver tissue histopathology was determined with HE at 2, 4, 6 and 8 h after Lps/D-Gal injection. Hepatocyte apoptosis was examined by TUNEL method. The expression of cathepsin B in liver tissues was investigated by immunohistochemistry, Western blot and RT-PCR. RESULTS: Compared with the normal group, massive typical hepatocyte apoptosis occurred in the model group; the number of apoptotic cells reached a maximum 6 h after injection. The apoptosis index (AI) in the protected group was clearly reduced (30.4 ± 2.8 vs 18.1 ± 2.0, P < 0.01 ). Cathepsin B activity was markedly increased in drug-treated mice compared with the normal group (P < 0.01). Incubation with LPS/D-Gal N at selected time points resulted in a timedependent increase in cathepsin B activity, and reached a maximum by 8 h. The expression of cathepsin B was significantly decreased in the protected group (P < 0.01). CONCLUSION: Cathepsin B plays an essential role in the pathogenesis of fulminant hepatic failure, and the cathepsin B inhibitor CA-074me can attenuate apoptosis and liver injury.