THE STUDY ON THE ROLE OF THE SUBSTRATE,INHIBITOR OF NOS AND PROVIDER OF NO IN RABBITS' INFECTION BY EIMERIA STIEDAI

To probe into the activity of inducible nitric oxide synthase(iNOS) in the liver,the concentration of nitric oxide(NO) in the serum and its inhibition or killness on coccidia of rabbits,the rabbits infected with Eimeria stiedai were injected with the substrate of nitric oxide synthase-L-arginine(L-Arg) with different concentrations,the nitric oxide donor-nitroglycerin(GTN) and the inhibitor of inducible nitric oxide synthase-L-aminoguanidine(L-AG) through the abdominal cavity.Then messure the activity of inducible nitric oxide synthase in the liver using test box of nitric oxide synthase activity.Messure the concentration of nitric oxide in the serum via the method of nitric acid reductase.Count the coccidian oosysts per gram feces(OPG) using McMaster's method.Score the pathologies according to anatomic structures of rabiits' livers and micoscopic pathological changes.The results showed that: after infected with Eimeria stiedai,the activity of inducible nitric oxide synthase of rabbits' liver chips and the concentration of nitric oxide in the serum increased gradually.The control group,L-arginine group,nitroglycerin group and L-aminoguanidine group reached the top 12 days after infected,and then decreased gradually and reached the level before infected at about 23days;L-arginine can enhance the activity of inducible nitric oxide synthase in the liver and make it release large amount of nitric oxide,so that inhibit or kill Eimeria stiedai and ease the pathologies caused by Eimeria stiedai;Nitroglycerin can release nitric oxide in vivo and inhibit Eimeria stiedai,so that ease the pathologies.On the contrary,L-aminoguanidine inhibits inducible nitric oxide synthase in the liver and reduces nitric oxide produced,so that the inhibition on Eimeria stiedai was weakened or even not existed andaggravated the pathologies.The results clues on that nitric oxide and inducible nitric oxide synthase indeed participate in the process of rabbits' infection with Eimeria stiedai and nitric oxide plays the role of inhibition or killing in the process of infection.