The study of nitric oxide's effect during Eimeria stiedai infection of rabbits

The activity of inducible nitric oxide synthase(iNOS) in the liver,the concentration of nitric oxide(NO) in the serum,the coccidian oosysts per gram feces(OPG)and anatomic structures of rabiits' livers and micoscopic pathological changes were studied.The rabbits infected with Eimeria stiedai were injected with the substrate of nitric oxide synthase—L-arginine(L-Arg) with different concentrations and the inhibitor of inducible nitric oxide synthase-L-aminoguanidine(L-AG) through the abdominal cavity.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,and L-aminoguanidine group reached the top after infected 12 days,and then decreased gradually and reached the level before infected at about 23days;L-arginine could enhance the activity of inducible nitric oxide synthase in the liver and make it release large amount of nitric oxide,inhibit or kill Eimeria stiedai and ease the pathologies caused by Eimeria stiedai;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 implied that nitric oxide and inducible nitric oxide synthase indeed participate in the process of rabbits' infection with Eimeria stiedai and nitric oxide played the definite role of inhibition or killness on coccidia of rabbites.