[Tumor necrosis factor-alpha, caspase-3 expression and hepatocyte apoptosis in fulminanting hepatic failure].
OBJECTIVE
To study the role of tumor necrosis factor-alpha (TNFalpha) and caspase-3 expression on hepatocyte apoptosis in experimental model of fulminant hepatic failure (FHF).


METHODS
Mouse experimental model of FHF was induced by lipopolysaccharide (LPS) and D-galactosamine (D-GalN). Serum TNFalpha level and TNFalpha mRNA expression in liver were tested by ELISA and reverse transcriptase PCR (RT-PCR) method, respectively. The expression of caspase-3 in liver tissue was determined by in situ hybridization. Hepatocyte apoptosis was examined by DNA agarose gel electrophoresis and TUNEL method. TNFalpha, caspase-3 and hepatocyte apoptosis were observed in different stages after drug administration. In addition, we observed the changes of above variables after pretreatment with anti-TNFalpha IgG1.


RESULTS
TNFalpha mRNA expression in liver increased significantly (0.91 +/- 0.75, that of normal control was 0.32 +/- 0.10) 2 to 4 hours after administration of LPS and D-GalN. The level of serum TNFalpha increased [(320.50 +/- 86.57) ng/L; that of normal control was (16.66 +/- 7.01) ng/L] and caspase-3 expressed to a slight extent, too. Typical manifestation of hepatocyte apoptosis appeared 8h after drug administration. 8 hours after drug administration the level of serum ALT and total bilirubin (TBil) remarkably increased [(560.66 +/- 60.20) U/L and (163.66 +/- 34.51) micro mol/L, respectively, that of normal control was (23.56 +/- 8.03) U/L and (14.90 +/- 4.80) micro mol/L, respectively] and the expression of caspase-3 reached the peak. 12 hours after drug administration, hepatocyte apoptosis and necrosis coexisted, and the level of serum ALT and TBil reached a peak [(668.30 +/- 78.69) U/L and (203.17 +/- 19.92) micro mol/L, respectively] whereas the expression of caspase-3 already decreased. Hepatocyte apoptosis and liver injury and the expression of caspase-3 could be blocked by antagonizing TNFalpha.


CONCLUSIONS
TNFalpha played an important role in hepatocyte apoptosis and liver injury in fulminant hepatic failure. The hepatocyte apoptosis induced by TNFalpha is correlated with the activation of caspase-3. Hepatocyte apoptosis occurs earlier than necrosis.
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000235:genetics*; D004195:Disease Models, Animal; D022781:Hepatocytes / Q000473:pathology*; D008099:Liver / Q000378:metabolism; D017093:Liver Failure / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases