Objective: To investigate the expression and role of early growth response (EGR-1) in early injury of small-for-size graft in rat liver transplantation.
Methods: Male Sprague-Dawley rats were randomly divided into three groups: Sham  operation group （SO group）; small-for-size graft group(30%graft group); whole graft group(100%graft group). The models of rat small-for-size liver transplantation were set up by two-cuff technique. Changes of AST in serum, pathology of liver, expression of EGR-1 and endothelin (ET)-1 in liver of three groups within 24 hours after reperfusion were compared.
Results: AST of SO group was significantly lower than that of the other two groups（P＜0.01），while AST of 100% graft group was lower than that of 30% graft group，especially at 6h and 24h after reperfusion （P＜0.01）. Apparent dilation of the sinusoid with disintegration and detachment of sinusoidal lining cells were observed in 30%graft group at 24h after reperfusion. There was no expression of EGR-1 and ET-1 in SO group, whereas expression of these two factors in 30%graft group  were significantly higher than that in 100% graft group within 24 hours after reperfusion.
Conclusions: Small-for-size graft injury was related to early over-expression of EGR-1 associated with upregulation of ET-1.