Effects Of Acupuncture At Neiguan On Heart Rate Variability And Substance P Content In Serum Of IBS-D Model Rats

ObjectIrritable bowel syndrome（IBS）is a common disease with abnormal digestive system function.The main symptoms include abdominal discomfort and changes in defecation habits,accompanied by mental and emotional abnormalities.The pathogenesis of the disease is not completely clear,and mental disorder may be one of the main factors.The changes of autonomic nerve function are closely related to psychological emotion,and heart rate variability（HRV）is the most simple and effective method to monitor autonomic nerve function;The abnormal expression of substance P is not only related to the occurrence of IBS,but also related to the abnormal functional state of autonomic nerve.Most patients with IBS will have the changes of HRV and the abnormal expression of substance P,suggesting that the occurrence of mental and psychological disorders in IBS may be related to HRV,and the changes of HRV may be related to the expression of substance P.Therefore,the model rats of diarrhea predominant irritable bowel syndrome（IBS-D）were prepared by the combination of acute stress and chronic stress.After the completion of modeling,acupuncture intervention was carried out.Starting with mental and emotional disorders and taking HRV as the starting point,the changes of HRV and substance P expression in IBS-D model rats were observed,and the improvement effect of acupuncture on autonomic nerve function was clarified,so as to provide experimental basis for clinical acupuncture treatment of IBS-D.MethodA total of 40 3-month-old SPF SD male rats with a body weight of 300 ± 20 g were used.After adaptive feeding for 1 week,they were randomly divided into 4 groups with 10 rats in each group:normal group,model group,Neiguan group and Taiyuan group.IBS-D model rats were prepared by the combination of acute stress and chronic stress.The normal group was fed normally without any treatment;The model group,Neiguan group and Taiyuan group were trained to grasp and wear rat clothes every day while modeling,and the changes of general conditions,body mass and emotional state of each group of rats before,after and during modeling were observed.After modeling,experiment1: connect BL-420 F biological function system to collect HRV ECG information after anesthesia between normal group and model group;In Neiguan group,bilateral Neiguan Points were needled during the process of collecting ECG information after anesthesia,and in Taiyuan group,bilateral Taiyuan points were needled during the process of collecting ECG information after anesthesia.Both groups received acupuncture once at the time of acupuncture and every 5 minutes,a total of 3 times.After the cardiac wave was stable,the change of HRV within 5 minutes was recorded.The changes of HRV in each group were recorded5 min before acupuncture,5min,10 min,15min during acupuncture and 10 min and 20 min after acupuncture.Experiment 2: after anesthesia in the same experiment,the content of substance P in serum of each group was collected and detected after acupuncture for 10 minutes.Result1.General conditions and body mass changes of rats in each group:There were no significant differences in mental state,hair color and compliance,daily activity and fecal properties of normal rats before and after modeling;The model group,Neiguan group and Taiyuan group all showed mental fatigue,slow response,withered and yellow hair,thin yellow and smelly feces in the middle and late stage of modeling,suggesting the success of modeling.In terms of body mass of rats in each group,the weight difference of rats in each group was not statistically significant before modeling.After 7 days of modeling,the weight of model group,Neiguan group and Taiyuan group was lower than that of normal group（all P<0.01）,and showed a decreasing trend;On the 14 th,21st and 28 th day of modeling,the body weight of rats in the four groups showed an upward trend,but the body weight of model group,Neiguan group and Taiyuan group was lower than that of normal group,and the difference was statistically significant（all P<0.01）.2.Comparison of fecal water content,sugar preference,open field test and abdominal retraction reflex（AWR）results of rats in each group:There was no significant difference in water content between the four groups（P>0.05）.After modeling,in terms of fecal water content,compared with the normal group,the fecal water content of other groups increased significantly,and the difference was statistically significant（all P<0.01）;After modeling,in terms of sugar water preference,compared with the normal group,the sugar water preference rate of other groups decreased significantly,and the difference was statistically significant（all P<0.01）;After modeling,in the open field experiment,compared with the normal group,the number of vertical and horizontal movements in other groups decreased significantly,and the difference was statistically significant（all P<0.01）;After modeling,in terms of AWR,compared with the normal group,the pain threshold of other groups decreased significantly,and the difference was statistically significant（all P<0.01）.3.Comparison of HRV results of rats in each group:Before modeling,there was no significant difference in HRV between rats in each group and normal group（P>0.05）.After modeling,compared with the normal group,SDNN（P<0.05）,RMSSD（P<0.01）,LF（P<0.01）and HF（P<0.01）increased;Compared with the model group,SDNN acupuncture for 5min（P<0.05）,10min（P<0.01）,15min（P<0.05）and 10min（P<0.05）in Neiguan group decreased significantly,RMSSD acupuncture for 5min（P<0.05）,10min（P<0.01）and 15min（P<0.05）,lf acupuncture for 5min（P<0.01）,10min（P<0.01）,15min（P<0.01）,10min（P<0.01）and 20min（P<0.05）,HF decreased at 5 min（P<0.01）,10 min（P<0.01）,15 min（P<0.01）,10 min（P<0.01）and 20 min（P<0.01）after acupuncture;Compared with the model group,HF in Taiyuan group decreased after acupuncture for 5min（P<0.05）,10min（P<0.01）,15min（P<0.01）,10min（P<0.01）and 20min（P<0.05）;Compared with Taiyuan group,HF（P<0.05）decreased more in Neiguan group at 5 minutes,SDNN（P<0.05）,RMSSD（P<0.05）,LF（P<0.05）and HF（P<0.01）decreased more at 10 minutes,and LF（P<0.05）and HF（P<0.05）decreased more at15 minutes,that is,Neiguan group was closer to the normal group.4.Comparison of substance P content in serum of rats in each group:Compared with the normal group,the content of substance P in serum of model group was significantly higher（P<0.01）;Compared with the model group,the content of substance P in serum of Neiguan group and Taiyuan group decreased（P<0.01,P < 0.05）,and the decrease range of Neiguan group was higher than that of Taiyuan group.The difference between the two groups was statistically significant（P<0.05）.ConclusionAcupuncture at Neiguan can improve the heart rate variability and restore the imbalance of autonomic nerve in rats with diarrhea type irritable bowel syndrome,which is related to acupuncture at Neiguan to enhance the excitation of sympathetic nerve and reduce the excitation of parasympathetic nerve.The decrease of the excitability of parasympathetic nerve may be related to the decrease of the content of serum P substance.