Liver injury after intermittent or continuous hepatic pedicle clamping and its protection by reduced glutathione

BACKGROUND: The debate is still going on about selec- tion of several clamping patterns during hepatectomy. The aim of this study was to assess the safety and preference of normothermic intermittent or continuous hepatic pedicle clamping and confirm the protective effect of reduced glu- tathione (GSH). METHODS: Thirty-two adult male healthy Sprague-Daw- ley (SD) rats were divided into groups of intermittent clamping and GSH absent (IA), continuous clamping and GSH absent (CA), intermittent clamping and GSH present (IP) and continuous clamping and GSH present (CP). The clamping manners were successively 40 minutes in con- tinuous clamping groups and two cycles of 20 minutes with an interval of 5 minutes in intermittent clamping groups, and reperfusion periods were 60 minutes. Experimental pa- rameters included levels of malonaldehyde ( MDA ) and Cu/Zn superoxide dismutase (SOD), pathological and ul- trastructural changes in liver tissues, activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in sera. RESULTS: In the same group, the activities of ALT and AST were significantly higher in post-clamping rats than in pre-clamping rats (P<0.05), but no significant differences were noted in levels of MDA and Cu/Zn SOD (P>0.05). The differences of all values between post-reperfusion rats and pre-clamping rats were significant (P<0.05). Patho- logical and ultrastructural changes could be observed, but no irreversible injury was present. The comparison of the groups showed that the values at relevant time points be- tween the intermittent and continuous groups were not sig- nificantly different (P>0.05). The values were significantly different between the GSH absent and present groups afterreperfusion (P<0.05). The morphological damages were also obviously alleviated in the GSH present group. CONCLUSIONS: Normothermic intermittent or conti- nuous hepatic pedicle clamping could cause reversible liver ischemia/reperfusion injury when the clamping time lasts 40 minutes. The injury extent seems to be similar. Conti- nuous clamping should be regarded as a proper method in liver surgery. GSH has been confirmed as an effective agent in preventing post-clamping liver injury.