一氧化氮和一氧化氮合酶在兔斯氏艾美耳球虫感染时作用的研究

THE STUDY OF NITRIC OXIDE AND NITRIC OXIDE SYNTHASE' EFFECTS ON RABBITS INFECTED WITH EIMERIA STIEDAI

本试验以腹腔注射的途径给予斯氏艾美耳球虫(E.stiedai)感染家兔不同浓度的一氧化氮合酶(NOS)底物L-精氨酸(L-Arg)和诱导型一氧化氮合酶(iNOS)抑制剂L-氨基胍(L-AG),对家兔球虫感染时血清中NO浓度和肝的iNOS活性及各试验组家兔的病变进行了研究。试验结果表明:家兔感染E.stiedai后,血清中NO浓度和肝匀浆的iNOS活性逐渐升高,感染对照组、添加L-Arg组和添加L-AG组3组均在感染后第12 d达到最高值,而后逐渐下降,于23 d左右下降到感染前的水平;L-Arg可增强肝的iNOS的活性,促进体内大量生成NO,产生对球虫的抑制或杀伤作用,减轻球虫感染引起的病变;而L-AG则抑制肝的iNOS活性,使体内生成的NO减少,对球虫的抑制作用减弱甚至消失,从而加重球虫感染引起的病变。结果提示:NO和iNOS参与了球虫感染过程,证明NO是抗E.stiedai感染的一种效应分子。

To study changes of the activity of iNOS in the liver and the concentration of NO in blood serum and NO＇ effect on inhibiting or killing coccidia, rabbits infected with Eimeria stiedai were injected with different concentrations of the substrate of NOS--L--Arg and the inhibitor of iNOS--L--AG through the abdominal cavity. Then study the activity of iNOS in the liver, the concentration of NO in blood serum, the number of coccidia oocysts per gram of faeces （OPG）, the anatomical and microscopical pathological changes of rabbits infected with Eimeria stiedai. The results show that when rabbits are infected with Eimeria stiedai, the activity of iNOS in liver homogenate and the concentration of NO in hood serum gradually increase and they both reach top at the twelfth day after infection in control group , L - Arg and L - AG groups. Then they graduall level before infection at about the 23th day. L - Arg could enhance the activity of iNOS in the y decrease to the liver and promote the production of NO so as to inhibit or kill coccidia and weaken the pathological changes caused by them ; on the contrary, L - AG can inhibit the activity of iNOS and reduce the production of NO, so the effect on inhibiting or killing coccidia is weakened or even disappears, thus aggravating the pathological changes caused by coccidia. The results indicate that NO and iNOS indeed participate in the course of coccidia infection, and NO plays a role in inhibiting or killing rabbit coccidia.