The Influence Of Analgesia Effect Of Electroacupuncture Combined With Fentannyl On Chronic Inflammatory Rats

Objective: The chronic inflammatory pain is common illness in the clinic. The primary noxious afferent neurotransmitters excitatory glutamate and substance P play a pivotal role in the development and maintenance of chronic inflammatory pain. In this study , the antinociceptive effect of electroacupuncture combined with fentanyl in the chronic inflammatory rats and the influence on the glutamate and substance P was observed to investigate the related analgesia mechanisms and provide essential theoretical evidence for the clinical therapy.Mathods: The arthritis model was established by injection of complete Freund's adjuvant 0.05 mL into the right ankle joint of rats. 30 adult SD rats weighing 200~ 250g were randomly divided into five groups , 6 rats in each group,including nomal control group, CFA group, EA group, fentanyl group and the combined application group. From the 4th day to the 10th day after CFA injection, 1 μg fentanyl was injected intrathecally daily in fentanyl group and the combined application group;on days 4 and 7 of the experiment, Han's acupoint nerve stimulator (HANS)was connected to the needles inserted into the acupoints "yanglingquan"and "zusanli"with the parameters(intensity< 2mA, frequency 2/100Hz, for 30min each time).The changes of hyperalgesia score which was the difference of two hind paws withdral lantency on hot plate were recorded and the changes of the quantity of Gluthrough capillary electrophoresis (CE) and the expression of substance P in the spinal dorsal horn were examined by the immunohistochemistry.Results :The quantity of glutamate in the lumbar spinal cord and the expression of SP in the spinal dorsal horn in the CFA group were higher than that of the other groups, while the hyperalgesia scores were lower .These changes of the CFA group had the statistical significance compared with the other groups (P<0.05 or P< 0.01).Compared with the EA group and fentanyl group, the quantity of glutamate and the expression of SP of the the combined application group decreased and the hyperalgesia score was elevated significantly (P<0.05 or P<0.01).Conclusion: Electroacupuncture can strengthen the antinociceptive effect of fentanyl;the combined application attenuate the central sensitization and prevent the development of the spinal neuroplastic changes to some extent.