A study on the changes and reducibility of substance P and vasoactive intestinal peptide in the intestinal wall of constipation model rats

Objective To observe the changes of substance P(SP)and vasoactive intestinal peptide(VIP)in the small intestine and colon of Wistar rats with constipation and to investigate the possibility of natural recovery of constipation caused by Rhubarb in rats.Methods 60 healthy Wistar rats were randomly divided into control group,constipation group and recovery group,20 rats in each group.The rats in constipation group and recovery group were given Rhubarb to set up constipation models of rats.The rats in recovery group were recovered naturally for six weeks,the levels of VIP and SP in small intestine and colon were detected by immunohistochemical stain and radioimmunoassay.Results As compared with those of control group,the levels of SP in small intestine and colon in constipation group and recovery group were significantly decreased(P0.05);the levels of SP in small intestine in recovery group were significantly higher than those of constipation group(P0.05);there was no significant difference in the levels of SP in colon between constipation group and recovery group(P0.05).The levels of VIP in small intestine and colon in constipation group were significantly higher than those in control group(P0.05).The levels of VIP in small intestine and colon in recovery group were significantly higher than those of constipation group(P0.05),however,which were obviously lower than those of control group(P0.05).Conclusion The long-term administration of Rhubarb can damage enteric nervous system through changing the expression of VIP and SP in small intestine and colon,with decrease of content of SP and the reactivity of VIP,however,six weeks after stopping the administration of Rhubarb,the expression of VIP and SP may recover partly.