Effect of Low-frequency Electroacupuncture on Substance P Expression in the Spinal Dorsal Horn in SNI Neuralgia Rats / 上海针灸杂志

ABSTRACT

Objective To investigate the intervening effect of low-frequency electroacupuncture on rat neuralgia and its regulating effect on substance P (SP) in the spinal dorsal horn. Method SD rats were randomized to normal, sham operation (sham SNI), operation (SNI) and electroacupuncture (SNI+EA) groups, 8 rats each. A rat model of neuralgia was made by spared sciatic nerve injury (SNI). Points Zusanli(ST36) and Kunlun(BL60) on the operation side were given 2 Hz electroacupuncture once daily for 14 days. The rat hind paw withdrawal threshold (PWT) was measured on the operation side to observe its pain hypersensitivity. SP-positive expression in the spinal dorsal horn on the operation side was determined by immunofluorescence. Result Operative side PWT decreased significantly in the SNI group of rats (P<0.01). Electroacupuncture increased operative side PWT in the SNI neuralgia rats (P<0.01). Pain threshold onthe healthy side had no marked change in the SNI group of rats (P>0.05). SP-positive expression in the spinal dorsal horn increased on the operation side (P<0.01) and also on the healthy side (P<0.05) in the SNI group of rats. Electroacupuncture decreased SP-positive expression in the spinal dorsal horn on the operation side in the SNI rats (P<0.01). Electroacupuncture did not significantly change SP-positive expression in the spinal dorsal horn on the healthy side (P>0.05). PWT on the operation and healthy sides and SP-positive cell expression in the spinal dorsal horn on the operation and healthy sides had no marked changes in the SNI group of rats (P>0.05). Conclusion Low-frequency electroacupuncture can relieve rat neuralgia. Its mechanism may be related to it inhibiting SP-positive expression in the spinal dorsal horn on the operation side.