氨基胍对饥饿大鼠小肠肌间神经丛神经元诱导型一氧化氮合酶表达的影响

Effect of aminoguanidine on expression of inducible nitric oxide synthase in neurons in the small intestinal nerve plexus of starved rats

目的评价氨基胍对饥饿大鼠小肠肌间神经丛神经元诱导型一氧化氮合酶（iNOS）表达的影响。方法雄性SD大鼠90只，体重230—270g，采用随机数字表法，将其随机分为3组：正常对照组（C组，n=10）、饥饿组（S组，n=40）和氨基胍＋饥饿组（A组，n=40），S组和A组无饲料供应，自由摄水，A组腹腔注射氨基胍150mg·kg^-1·d^-1。s组和A组分别于饥饿3、5、7、9d时取10只动物，采用葡聚糖蓝染色法测定小肠传输比率，然后处死动物，取小肠组织，采用NADPH-黄递酶组织化学染色法测定回肠肌间神经丛神经元iNOS表达。结果与C组比较，S组和A组各时间点小肠传输比率降低，回肠肌间神经丛神经元iNOS表达上调（P〈0．05或0．01）；与S组比较，A组于饥饿3、5、7d时小肠传输比率升高，回肠肌间神经丛神经元iNOS表达下调（P〈0．05或0．01）。结论氨基胍改善饥饿大鼠小肠运动功能的机制与下调小肠肌间神经丛神经元iNOS表达有关。

Objective To evaluate the effect of aminoguanidine on expression of inducible nitric oxide synthase （iNOS） in neurons in the small intestinal nerve plexus of starved rats. Methods Ninety male SD rats weighing 230-270 g were randomly divided into 3 groups： group normal control （group C, n = 10）; group starvation （group S, n =40） and group starvation ＋ aminognanidine （group A, n = 40）. The animals were allowed free access to water but no food during starvation in S and A groups. In group A the animals were given aminoguanidine 150 mg. kg-1. d-1 intraperitoneally during starvation. Ten animals were sacrificed at 3, 5, 7 and 9 d of starvation respectively and intestine specimens were taken for determination of ratio of intestinal transit using dextran blue-2000 as indicator. Then the specimens of intestinal myenteric nerve plexus of ileum were collected and stained by histochemistry with nicotinamide-adenine dinucleotide phosphate-d for determination of iNOS expression. Results Starvation significantly reduced the small intestinal transit and increased iNOS expression in neurons in the myenteric nerve plexus of small intestine in proportion to days of starvation in group S compared with group C. lntraperitoneal aminoguanidine significantly attenuated the starvation-induced changes in intestinal transit and iNOS expression. Conclusion Aminoguanidine can attenuate the up-regulation of the expression of iNOS in neurons in the myenteric nerve plexus of small intestine induced by starvation and is helpful in promoting the intestinal transit in starved rats.