WANG Yili, LV Peiran, HE Wei, ZHANG Xiaoning, CHEN lizhen, DUANMU Chenglin，  WANG Xiaoyu，JING Xianghong

(1 Institute of Acupuncture and Moxbustion China academy of Chinese Medical Science, Beijing 

100700)

Abstract：Objective： To explore the mechanism and efficiencyof acupoint sensitization by observing the distribution of body sensitized acupoints in chronic colitis model rats and their dynamic changes with the disease status.Methods：  Six to nine week-old male Sprague-  Dawley rats were used in this study. 1.Evans Bluewas  injected  via  caudal  vein  in  chronic  colitis  model  ratsand  location  changes  of  EB  exudates  was observed at 7d, 14d, 21d, 28d to explore the location of sensitized acupoints and their dynamic change during course of disease. 2.Thermal pain threshold and mechanical pain threshold in lower limbs of chronic colitis model rats were detected before and 7d, 14d, 21d, 28d after modeling to find their dynamic change during course of disease. 3.To analyze the mechanism of the formation of sensitized acupoints by observing expression  changes  ofneurogenic  inflammation  and sympathetic  sensory  coupling  phenomenonrelated substances.Immunofluorescence and Western Blot were used to detectneurogenic inflammation reaction in Dorsal root ganglion (DRG) and sensitized acupoint region as well as abnormal sympathetic sprouting induced by sympathetic  sensory coupling phenomenon in  chronic colitis model rats at 7d, 14d. Release of painrelated substances such as CGRP, andexpression of Tyrosine hydroxylase,the marker of sympathetic nervous system were detected at the same time. 3.Electro-acupuncture (EA)  intervention on sensitized acupoints in chronic colitis rats and thermal pain threshold and mechanical pain threshold in lower limbs of chronic colitis model rats were detected 7d, 14d after EA treatment to estimatecurative effect of EA. Meanwhile, Release of painrelated substances such as CGRP, andexpression of Tyrosine hydroxylase were observed to explore  the mechanism of acupoint sensitization through sensory sympathetic coupling and neurogenic inflammation levels. Results：  1. EB exudation points were found near the Zusanli point area 7d, 14d, 21d and 28d after modeling in chronic colitis model rats, and the occurrence rate of EB exudation points  in  model  group  was  statistically  different  from  that  in  the  control  group  (p=0.0013).  2.  After modeling, the mechanical pain threshold and thermal pain threshold of the model group were significantly decreased,  and  were  the  lowest  at  each  time  point  (7d,  14d,  21d,  28d),  with  statistical  significance compared with other three groups(p<0.05). 3. 7d after modeling,sympathetic nerve sprouting trend was observed in DRG (L5), and grew more at 28d. Compared with model group, those in EA group, EA inhibited the degree of sympathetic sprouting in DRG. Meanwhile, TH positive nerve fibers did not enter the somain DRG of control group and sham operation group. 4.There was no significant difference in the expression of CGRP  in  the  plantar  skin,  Zusanli  skin,  Zusanli  muscle  and  DRG  in  each  group(p>0.05)  at  7d  and  14d.Conclusion：  1. Surface sensitization acupoints of chronic colitis model ratsmainly distributed on the L5-S1 ganglion segment skin, focus on Zusanli area. 2. Somatic hyperalgesia occurredin rats with chronic colitis, and  sympathetic  sprouting  occurred  in  DRG  of  L5-S1.  3.  Electro-acupuncture  on  sensitization  acupoints couldalleviate somatic hyperalgesia and degree of sensory sympathetic coupling in rats with chronic colitis.

Key words：Electroacupuncture, Sensitive Point, Chronic Colitis, Neuronal Inflammation