Effect of microwave coagulation on mechanical allodynia and leakage of Evans blue in rats with neuropathic pain / 中华神经医学杂志

ABSTRACT

Objective To observe the mechanical allodynia of affected extremity and the leakage of Evans blue when performing thermal stimulation on the threshold, and explore the efficacy of microwave on rats models of neuropathic pain and the optimum temperature and other ideal parameters for this treatment by performing microwave coagulation treatment under different temperatures to them.Methods Forty-two SD rats were induced the models of spared nerve injury (SNI) on sciatic nerves,then were equally randomized into 3 groups control group (only inserting microwave coagulation needle but not heating), 42℃ microwave coagulation treatment group and 60℃ microwave coagulation treatment group (n=14). The 50% paw withdrawal threshold of the affected extremity was measured 1 d before and 1, 2, 4, and 6 weeks after treatment. The leakage of Evans blue in injured tissue of the affected extremity when performing thermal stimulation on the threshold was observed 2 weeks after treatment and compared between each 2 groups. Results The 50% paw withdrawal threshold was stable in control group, 42℃ microwave coagulation treatment group and 60℃ microwave coagulation treatment group 1 d before treatment; no significant differences were noted between each 2 groups (P＞0.05). The 50% paw withdrawal threshold of 60℃ microwave coagulation treatment group 1, 2, 4, 6weeks after treatment was significantly increased as compared with that in the control group and 42℃microwave coagulation treatment group (P＜0.05). The concentrations of leakage of Evans blue in the 42℃ microwave coagulation treatment group ([9.96±1.01] g/g) and 60℃ microwave coagulation treatment group ([7.41±1.37] g/g) were significantiy decreased as compared with those in the control group ([14.8±2.88] g/g, P＜0.05). Conclusion Microwave coagulation can improve the mechanical hyperalgesia of in rats with neuropathic pain induced by SNI, and 60℃ is the proper temperature.Inflammation is inhibited by microwave coagulation and this might be one of the mechanisms to alleviate the pain.