Study On Expression Of Neural Nitric Oxide Synthase In Infantile Hypertrophic Pyloric Stenosis And Outcome Of Arginine Treatment

Objective This study aimed to discuss the relationship between decreased expression of neural Nitric Oxide Synthase(nNOS)at pylorus and Infantile Hypertrophic Pyloric Stenosis(IHPS).Also discuss outcome of L-arginine treatment and provide theoretical basis to clinical use L-arginine.Methods Wistar rats were randomized divided into model group,treatment group and control group.Control group were fed as usual.Those of research group were fed with nNOS inhibitor 14 days after pregnancy until delivery.All baby rats of research group were randomized divided into 4 groups,model group,low dose group,medium dose group and high dose group.Baby rats of different group were fed with 0, 100mg/kg·d^-1,200mg/kg·d^-1and 400mg/kg·d^-1of L-arginine respectively on top of nNOS inhibitor since birth to 42 days.Baby rats were weight 21,28,35 and 42 days after birth,and killed on 42 days to weigh stomach and 10cm of intestine.Width of pyloric muscle was measured on tissue slice.Neural cells within pyloric muscle with positive nNOS expression on immunohistochemistry were calculated.All the data were shown as mean±standard deviation((?)±S).P value less than 0.5 was considered significant.Results(1)weight:Body weight of model group and low,medium,high dose groups were lower than control group significantly(F=9.276,P＜0.05)There were no significant difference between low,medium,high dose groups and model group (q=0.293,0.108and0.376,P＞0.05).(2)muscle thickness:Comparing with control group,width of pyloric muscle in model group and low,medium groups were significantly wider(q=2.959,2.597and2.142,P＜0.05).That of high dose group was not different from control group significantly(q=1.119,P＞0.05).But,thinner then that of model group significantly(q=0.293,P＜0.05).(3)cell number with positive nNOS expression:Comparing with control group,cell number with positive nNOS expression in model group and low,medium groups were significantly smaller (q=10.477,3.537and3.001,P＜0.05).But,cell numbers with positive nNOS expression in low,medium,high dose groups were Significantly larger than model group(q=8.414,6.437and7.623,P＜0.05).That of high dose group was significantly larger than low dose group(q=2.082,P＜0.05).(4)Weight of stomach was not different significantly between these 5 groups.(5)Weight of intestine:Weight of intestine in model group and low,medium dose groups were more than that of control group significantly(q=3.314,2.038and2.233,P＜0.05).(6)Weight of stomach and intestine were positively related to body weight(r=0.299,0.345,P＜0.05).Conclusion(1)Decreased expression of nNOS at pylorus play an important role in IHPS.(2)L-arginine treatment can reduce pyloric hypertrophy in L-NAME model rats of IHPS.As a precursor substance of NO,L-arginine can induce expression of nNOS.(3)Among these 3 different dose groups,high dose of 400mg/kg has most significant outcome.