Objective To observe the effect of medicated-catgut embedding at"Changqiang"(GV 1)on regional pain reaction and expression of p 38 MAPK in the dorsal horn of spinal cord in anus incisional pain rats

so as to explore its analgesic mechanism.Methods Forty male SD rats were randomly divided into control

model

GV 1-embedding and sham acupoint embedding groups(n=10 rats in each group).The anus incisional pain model was established by making a radial incision(about 10 mm length)at the left lithotomy position of the anus with a surgical knife

and the mechanical pain threshold(PT)was measured by using a Von Frey before and 4

8

12

24 hafter operation.The medicated-catgut(about 12.5 mm length/kg body weight)was implanted in the subcutaneous tissue of GV 1 region.The immunoactivity of p 38 MAPK was determined by immunohistochemistry.Results Compared with the control group

the mechanical PTs were significantly decreased 4

8

12 and 24 h after operation both at the site of incision and about 15 mm proximal to the site of incision in the model group(P<0.05)

and the immunoactivity of phosphorylated(p)-p 38 MAPK in the superficial layer of dorsal horns of lumbar spinal cord was significantly increased(24 h)after operation(P<0.05).Compared with the model group

the PTs were significantly increased 8

12 and 24 h after operation at the site of incision

and 12 hand 24 hat the site about 15 mm proximal to the incision region(P<0.05)

and the immunoactivity level of p-p 38 MAPK was significantly down-regulated in the GV 1-embedding group(P<0.05).No significant changes were found in the PT and p-p 38 MAPK immunoactivity levels in the sham acupoint embedding group(P>0.05).Conclusion Medicated-catgut embedding at"Changqiang"(GV 1)has an analgesic effect in anus incisional pain model rats

which may be related to its effect in down-regulating the expression of p 38 MAPK in the dorsal horn of lumbar spinal cord.