The Research Of The Analgesic Effects And Mechanisms By Acupuncture At Jiaji Points In Rat Of Incisional Pain

Objective:(1) Through the establishment of a rat model of incisional pain,to observe the effect of the application of acupuncture Jiaji points and continuous acupoints infusion of analgesic drugs at Jiajji in the treatment of postoperative pain from rat behavior;(2) To observe the effect of substance P and expression of neurokinin 1 receptor in lumbar enlargement of spinal cord in the rats by electroacupuncture or continuous infusion of analgesic drugs at Jiaji points, we could explore the analgesic mechanisms of acupuncture Jiaji points, it was very important for the basis of clinical application.Methods:60 healthy male SD rats, were randomly divided into sham control group,PI group,CSI group,EA group and CAI group,12 in each group. Plantar incision pain model in rats was established according to the method of Brennan,rats in five groups at preoperative 1h and 6,24, 48h after operation, mechanical withdrawal threshold(MWT) and thermal withdrawal latency(TWL) were evaluated, substance P of lumbar enlargement in the spinal dorsal horn, and neurokinin 1 receptor (NK1R) in lumbar enlargement of the spinal cord were analysed by Immunohistochemical method, content of substance P was determined by enzyme linked immunosorbent assay.Results:(1)Changes in mechanical withdrawal threshold(MWT):five groups of rats with experimental basis of mechanical withdrawal threshold values showed no significant difference between them; the sham control group at each time point of the mechanical withdrawal threshold compared no significant difference; PI group, CSI group, EA group, CAI group compared with sham control group, MWT decreased significantly at 6h,24h,48h after operation (p<0.05); CSI group, EA group, CAI group compared with PI group, MWT increased significantly at 6h,24h,48h after operation (p<0.05);CAI group compared with CSI group and EA group, MWT increased significantly at 6h,24h,48h after operation (p<0.05);(2) Changes of thermal withdrawal latency(TWL):compared with the sham control group, TWL decreased significantly in PI group at 6h,24h, 48h after operation (P<0.05); CSI group, EA group, CAI group compared with the sham group, TWL increased significantly at 6h,24h,48h after operation (p<0.05); CAI group compared with CSI group and EA group, TWL increased significantly at 6h,24h,48h after operation (p<0.05);(3)Changes of integrated optical density value of substance P and neurokinin 1 receptor in rat lumbar enlargement of the spinal cord at 48h after operation:compared with the sham group, IOD of positive cells of substance P and neurokinin 1 receptor of PI group rise obviously(P<0.05); compared with PI group, IOD of positive cells of substance P and neurokinin 1 receptor of CSI group,EA group and CAI group reduced obviously(P<0.05); compared with CSI group and EA group,IOD further decreased significantly in CAI group (P<0.05);(4)Changes of the content of substance P in rat lumbar enlargement of the spinal cord at 48h after operation:compared with the sham control group, the content of substance P increased significantly in rat lumbar enlargement of the spinal cord in PI group, CSI group, EA group and CAI group(P<0.05); compared with the PI group, the content of substance P decreased significantly in rat lumbar enlargement of the spinal cord in CSI group, EA group and CAI group(P<0.05); compared with the CSI group and EA group, the content of substance P decreased significantly in rat lumbar enlargement of the spinal cord in CAI group(P<0.05).Conclusion:Electroacupuncture and continuous acupoint infusion of analgesic drugs at Jiaji could produce obvious analgesic effect, the analgesia effect of continuous acupoint infusion at Jiaji was better than subcutaneous analgesia. The analgesic mechanism of acupuncture at Jiaji points may be related to the inhibition expression of substance P and neurokinin 1 receptor in rat lumbar enlargement of the spinal cord in a rat model of incisional pain.