Objective To observe the regulatory effect of acupotomy lysis on SP level in spinal cord and tissues above spinal cord of rats with knee osteoarthritis.Methods 60 healthy SD rats were randomly divided into normal control group,model group,electro-acupuncture(EA)group,and acupotomy lysis(AL)group.Mix 4%papain solution with 0.3 mol/L cysteine solution in the ratio of 1∶1.After pausing for 0.5h,inject the mixture,20 μl each time,into the left knee joint cavities of rats in model,AL,and EA groups on the day of 1,4,7.After 4 weeks AL group was treated with acupotomy lysis and EA group with electro-acupuncture.Three weeks after treatment,take samples of spinal cord,midbrain,pituitary gland,thalamus,and hypothalamus from the swellings of rats'waists.Measure the content of SP therein separately.Results Compared with normal control group,there was a significant rise in the content of SP in spinal cord and the tissues above spinal cord of model group rats (P＜0.05,P＜0.01),and there was a significant rise in spinal cord,pituitary gland,thalamus and hypothalamus of EA group rats (P＜0.05,P＜0.01);in AL group,there was a significant rise in spinal cord,pituitary gland,thalamus,and there was no statistically difference in hypothalamus and midbrain.Compared with normal control group,there was a significant rise in spinal cord (P＜0.05)and a significant decrease in the SP contents in hypothalamus(P＜0.05,P＜0.01)in EA group.There was no statistically difference between EA group and AL group except in hypothalamus(P＜0.05).Conclusion Acupotomy lysis has positive functions in regulating SP content in centrum of rats with knee osteoarthritis,which helps easing pain.