Effect Of Houpu Sanwu Decoction On Gastrointestinal Motility In Rats:based On NO-cGMP-PKGI Pathway

Objective: To study the effect of Houpu Sanwu Decoction on the level of nitric oxide（NO）and the expression of its downstream signal protein in stomach and jejunum of rats with gastrointestinal motility disorder,and to clarify the intervention effect of Houpu Sanwu Decoction on NO-c GMP-PKGI signal pathway,so as to provide theoretical basis for the clinical application of Houpu Sanwu Decoction,and to make a new exploration for the targeted treatment of gastrointestinal motility disorder（DGIMD）with traditional Chinese medicine.Methods:（1）Establishment and evaluation of rat model of gastrointestinal motility disorder: 20 male SD rats were randomly divided into model group and control group.The rats in the model group were intraperitoneally injected with 20%L-arginine solution,while the rats in the control group were intraperitoneally injected with 0.9% normal saline.5 days later,the success of the rat model of gastrointestinal motility disorder was evaluated by the changes of body weight,intestinal propulsion rate,plasma motilin（MTL）and NO.（2）Mechanism of promoting effect of Houpu Sanwu Decoction on gastrointestinal motility in rats: another 40 clean male SD rats were randomly divided into four groups:（1）control group;（2）model group;（3）Houpu Sanwu decoction group;（4）S-Methylisothiourea Sulfate（SMT）group.Rats in model group,Houpu Sanwu Decoction group and SMT group were injected intraperitoneally with 20%L-Arg to induce gastrointestinal motility disorder,while rats in control group were injected with the same dose of normal saline.After the establishment of gastrointestinal motility disorder model,four groups of rats were treated with normal saline（control group and model group）,Houpu Sanwu Decoction（Houpu Sanwu Decoction group）and SMT（SMT group）.7 days later,the recovery of rats with gastrointestinal motility disorder was evaluated by the changes of body weight,intestinal propulsion rate,MTL and NO.The tissue structure changes and the expression of inducible nitric oxide synthase（i NOS）in stomach and jejunum were observed by HE staining and immunohistochemical staining.Finally,ELISA and Western-Blot techniques were used to detect the content of cyclic guanosine monophosphate（c GMP）and the protein expression levels of inducible nitric oxide synthase（i NOS）,soluble guanylate cyclase（s GC）and c GMP-dependent protein kinase GI（PKGI）in stomach and jejunum of rats in each group.Results: 1.After intraperitoneal injection of 20%L-Arg,the body weight,intestinal propulsion rate and MTL of the model group were significantly lower than those of the control group,while NO was significantly higher than those of the control group.2.After successful modeling,the contents of NO and c GMP in the stomach and jejunum of the model group increased significantly,and the protein expression levels of i NOS,SGC and PKGI also increased significantly.After 7 days of intervention with Houpu Sanwu Decoction and SMT,compared with the model group,the weight of rats in Houpu Sanwu Decoction group and SMT group increased,the contents of NO and c GMP in stomach and jejunum of rats decreased,and the protein expression levels of i NOS,s GC and PKGI decreased.3.The expression of i NOS in Houpu Sanwu Decoction group was higher than that in SMT group,while the expression level of s GC and PKGI protein in Houpu Sanwu Decoction group was lower than that in SMT group,and the content of c GMP was also lower than that in SMT group.Conclusions: 1.Intraperitoneal injection of 20%L-Arg solution can induce gastrointestinal motility disorder in rats.2.The mechanism of gastrointestinal motility disorder in rats may be related to L-Arg up-regulating the expression of i NOS,producing a large amount of NO,and then activating NO-c GMP-PKG-I pathway.3.The promoting effect of Houpu Sanwu Decoction on gastrointestinal motility in rats may be related to the inhibition of i NOS expression,inhibition of NO production and down-regulation of NO-c GMP-PKGI pathway.