Changes of nitric oxide and nitric oxide synthase during hepatic ischemia/reperfusion of rat

Objective To explore changes and effects of nitric oxide(NO) as well as nitric oxide synthase(NOS) during liver ischemia/reperfusion(I/R) injury of rats.Methods Twenty-four healthy male SD rats were randomly divided into 3 groups(8 animals per group).Group 1 was served as sham operated control.Both Group 2 and Group 3 were subjected to 45 min lobar,rather than total hepatic ischemia and 60 min reperfusion.Group 3 were pretreated with L-Arg(300 mg/kg) via the dorsal penis vein additionally.Blood samples(2 ml) were drawn from inferior vena cava for biochemistry tests,such as ALT,AST,and LDH.Injured liver lobes were excised for histology and testing SOD,MDA,XOD,NO and NOS.Results Rats in group 2 showed significantly higher iNOS levels and lower NO levels than those in group 1.NO and eNOS were increased in Group 3 compared with those in group 2(P0.05).The L-Arg administration significantly reduced the hepatic lesions.Conclusion NO has a protective effect on liver I/R injury in rats,and different isoforms of NOS may be involved in this process.