【作者】 李方正；

【导师】 尹逊河；

【作者基本信息】 山东农业大学 ， 基础兽医学， 2004， 硕士

【摘要】 本试验以饲喂的途径给予感染家兔NO的前体L-精氨酸(L-arginine),以腹腔注谢的途径给予感染家兔诱导型一氧化氮合酶(iNOS)的抑制剂L-氨基胍(L-AG), 对家兔斯氏艾美耳球虫(E.stiedai)感染时血清中的一氧化氮(NO)浓度、肝的诱导型一氧化氮合酶(iNOS)的活性、肝中iNOS的分布以及各试验组家兔球虫感染时的病变进行了研究,以探讨一氧化氮和一氧化氮合酶在家兔斯氏艾美耳球虫感染时的作用。试验结果表明:家兔感染E.stiedai后,其血清NO浓度随感染时间的延长而逐渐升高,其肝的iNOS活性明显上升(P<0.01),剖检后出现典型的球虫感染的症状;在家兔球虫感染的过程中,每日连续给予L-Arg,家兔血清中NO的水平与感染对照组和正常对照组以及L-AG组有显著差异,而且该组家兔增重明显、每克粪便中卵囊数(OPG)较低、肝脏的肉眼和显微病变均较轻微;在家兔球虫感染的过程中,每日连续给予L-AG,不但加重了家兔的肝道组织显微病变,而且使肝组织切片中的球虫数量增多。用L-AG处理还使感染家兔的OPG值和肝病变记分等指标出现不同程度的升高,但与感染对照组的相比未见显著性差异。另外,无论是NO测定结果,还是iNOS活性测定结果均表明,iNOS抑制剂对感染E.stiedai家兔体内NO的生成均有较好的抑制作用,L-AG处理组家兔血清NO水平或肝脏iNOS活性值均与正常对照组和感染对照组存在着显著的差异(P<0.01)。结果提示,在家兔感染球虫过程中,球虫子孢子在胆管上皮细胞繁殖,<WP=7>激活了肝细胞中iNOS,iNOS被激活后,能在相当长的时间内以恒定的速度合成大量的NO,继而引起NO的浓度升高,体内大量生成的NO对球虫具有一定的毒性作用。增加外源性的L-Arg可促进NO的产量进而提高家兔对球虫的繁殖产生抑制,减轻球虫感染后的病变。而iNOS的抑制剂逆转杀灭球虫的活性,削弱了家兔对球虫的抵抗力,加重了肝的病变,阻碍了家兔的生长。证明NO是在家兔E.stiedai感染过程中发挥作用的一种效应分子。更多还原

【Abstract】 The effects of NO during E.stiedai infection processes using iNOS inhibitors such as L-AG and L-arginine(the substrate of NO) have been studied in this research.The experimental results showed that the NO of serum levels and NOS activity of liver in infective control groups were significantly higher than those of control one (P<0.01). The rabbit of infective control groups showed typical pathological changes of infected by E.stiedai. These results indicated that L-Arg might successfully activate the NO production in serum and the iNOS activity of the liver. This group of rabbit had significantly increasing body weight,OPG and lighter pathological changes in liver than in other group.The results indicated that L-AG might successfully inhibit the NO production in serum.The clinical signs,gross and histologic lesions and coccidiosis in L-AG treated group were exacerbated. The results showed in comparison with the control, there were significant differences of iNOS activities and NO solution at different time points (P<0.01).It was suggested that the sporozoites might reproduce in the epithelia of the bile duct which activated the activity of iNOS. The NO from iNOS will kill the E.stiedai partially. L-Arg given by oral may enhance capacity of the rabbits to defend against E.stiedai and lighten the pathological changes in liver. On the other hand the L-AG may inhibit the iNOS activity, decrease the NO production in serum and L-AG may aggravate pathological change and decrease the immunity against E.stiedai infection in rabbits.The experimental results imply that NO which is produced during E.stiedai infection processes has some toxic effect on E.stiedai parasite, and some beneficial effect on rabbit.更多还原