加巴喷丁对神经病理性痛大鼠脊髓胶质细胞活化的影响

目的 评价加巴喷丁对神经病理性痛大鼠脊髓胶质细胞活化的影响.方法 雄性SD大鼠24只,体重180～220 g,随机分为3组(n=8):假手术组(S组)、坐骨神经慢性压迫性损伤组(CCI组)和加巴喷丁组(G组).CCI组和G组采用坐骨神经慢性压迫性损伤法建立大鼠神经病理性痛模型;S组只暴露坐骨神经,不结扎.G组于术后8 d时开始胃内灌注加巴喷丁50mg/kg(溶于5 ml生理盐水中),2次/d,持续5 d;CCI组胃内灌注0.9%生理盐水5 ml,2次/d,持续5 d;S组不给予任何药物.分别于术前1 d、术后7、15 d时测定机械痛阈,并于术后15 d时断头处死大鼠,取L4.5脊髓组织,采用免疫组化法检测星形胶质细胞和小胶质细胞的活化水平.结果 与S组比较,CCI组术后7、15 d时机械痛阈降低,脊髓星型胶质细胞和小胶质细胞活化水平升高,G组术后7 d时机械痛阈降低(P＜0.05);与CCI组比较,G组术后15 d时机械痛阈升高,脊髓星形胶质细胞和小胶质细胞活化水平降低(P＜0.05).结论 加巴喷丁可抑制大鼠脊髓星形胶质细胞和小胶质细胞的活化,从而减轻神经病理性痛.

Effect of gabapentin on activation of glial cells in spinal cord after chronic constrictive injury to sciatic nerve in rats

Objective To investigate the effect of gabapentin on the activation of glial cells in the spinal cord after chronic constrictive injury (CCI) to sciatic nerve in rats.Methods Twenty-four male SD rats weighing 180-220 g were randomly divided into 3 groups (n = 8 each): group Ⅰ sham operation (group S), group Ⅱ CCI and group Ⅲ gabapentin + CCI. Right sciatic nerve was exposed and 4 loose ligatures were placed with 6-0chromic catgut. Seven days after operation gabapentin 50 mg/kg in 5 ml was given by intragastric gavage twice a day for 5 days in group Ⅲ. Paw withdrawal threshold to mechanical stimulation with von Frey filaments was measured one day before (baseline) and at 7, 15 d after operation. The animals were killed at 15 d after operation. The lumbar segment L4-5 of the spinal cord was removed. Immunohistochemical double mark technique was used to detect the activation of astrocytes and microglias in the spinal cord. Results Paw withdrawal threshold to mechanical stimulation was significantly decreased on the 7th and 15th day after CCI operation in group CCI as compared with group S. After 5 day treatment with gabapentin, the withdrawal threshold to von Frey hair stimulation was significantly higher in group Ⅲ than in group Ⅱ . The activation of astrocytes and microglias in the spinal cord was significantly enhanced in group CCI as compared with group S. Treatment with gabapentin significantly inhibited CCI-induced activation of astrocytes and microglias in the spinal cord. ConclusionGabapentin reduces neuropathic pain by inhibiting activation of glial cells in the spinal cord.