Production of free radical species during Eimeria maxima infections in chickens
Production of free radical species during Eimeria maxima infections in chickens
复制标题
DOI：
10.1093/ps/76.6.814
复制
发表时间：
1997-06-01
期刊：
影响因子：
4.4
通讯作者：
Allen, PC
中科院分区：
文献类型：
--
作者：
Allen, PC
通过5项实验研究了鸡感染球虫艾美耳虫感染过程中一氧化氮（NO）和超氧阴离子（O-2(-)）的产生，以探讨这两种自由基在鸡感染过程中的作用。通过分析血浆和肠粘膜中NO的稳定代谢产物NO2- + NO3-来估计一氧化氮的产生。从粘膜匀浆中β -烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶的活性估计了O-2（-）生产的潜力。接种后约6 d， NO2- + NO3-水平达到最大值，此时粘膜损伤程度高，卵囊脱落。感染后粘膜内NADPH氧化酶活性明显升高。因此，在当时，这些自由基及其反应产物有可能对粘膜组织造成氧化破坏。NO2- + NO3-水平并没有随着感染剂量的增加而逐步增加，这表明NO的产生可能受到感染免疫反应中阐述的其他因素的转录后调节，或者可能受到底物限制的控制。两株最大E.菌株的比较表明，一株菌株的毒力与NO的产生没有直接关系。在感染期间，由于NADPH氧化酶活性增加，O-2（-）的产生增加，可能导致与吸收不良无关的类胡萝卜素色素水平降低。
Five experiments were conducted to investigate the production of nitric oxide (NO) and superoxide anion (O-2(-)) during infections of chickens with the coccidial parasite, Eimeria maxima, in order to assess the importance of these free radical species in the pathogenesis of the infections. Nitric oxide production was estimated by analyzing NO2- + NO3-, stable metabolites of NO, in the plasma and intestinal mucosa. The potential for O-2(-) production was estimated from activities of beta-nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in mucosal homogenates. Levels of NO2- + NO3- reached maximum values at about 6 d postinoculation, a time when mucosal damage was high and oocysts were being shed. The activity of NADPH oxidase in infected mucosa was also increased. Thus, at that time, there was a potential for oxidative destruction of mucosal tissue from these free radicals and their reaction products. Levels of NO2- + NO3- did not increase in a stepwise manner with increasing infective dose, suggesting that production of NO may be regulated post-transcriptionally by other factors elaborated by the immune response to infection, or may be controlled by substrate limitations. A comparison of two E. maxima strains indicated that the virulence of a strain was not directly related to NO production. Increased production of O-2(-) due to increased NADPH oxidase activity during infection may cause a reduction in levels of carotenoid pigments that is unrelated to malabsorption.