复合维生素B对坐骨神经结扎大鼠痛觉过敏和背根神经节神经元nNOS表达的影响

EFFECTS OF B-VITAMINS ON HYPERALGESIA AND NITRIC OXIDE SYNTHASE EXPRESSION OF DORSAL ROOT GANGLIA NEURONS INDUCED BY CHRONIC CONSTRICTION INJURY

目的观察复合维生素B对神经病理性疼痛大鼠机械痛敏、热痛敏以及L5背根神经节(DRG)神经元型一氧化氮合酶(nNOS)表达的影响。方法采用坐骨神经结扎(CCI)模型,复合维生素B(含B1B6B12110.01,5mg/kg即B15mg,B65mg和B120.05mg/kg)口服给药,连续14天。分别于术前(0天)及术后1,3,5,7,9,11,14天以vonFrey细丝法和热辐射法测定机械缩足反射阈值(mechanicalwithdrawalthreshold,MWT)和热缩足反射潜伏期(thermalwithdrawallatency,TWL);以免疫组织化学结合计算机图像分析的方法,观察复合维生素B对L5背根神经节神经元nNOS表达的影响。结果口服不同剂量的复合维生素B(5mg/kg/d、10mg/kg/d、30mg/kg/d),减轻了大鼠机械痛敏和热痛敏,并抑制了背根神经节nNOS的表达。结论口服复合维生素B具有减轻坐骨神经结扎大鼠机械痛敏和热痛敏的作用,其作用机制可能是抑制初级感觉神经元nNOS的表达和神经元的敏化。

Objective: To investigate the effect of B-vitamins on mechanical and thermal hyperalgesia and neuronal nitric oxide synthase (nNOS) expression in dorsal root ganglion (DRG) neurons in rats with neuropathic pain. Methods: Chronic constriction injury (CCI) model was adopted. Drugs, including combination of thiamine/pyridoxine/cyancobolamin (TPC, 1:1:0.01, 5～30 mg/kg),were administrated orally for 14 days. Mechanical withdrawal threshold and thermal withdrawal latency were measured on 0,1,3,5,7,9,11,14 post-operative days. Expression of nNOS of ipsilateral L_5 DRG were detected by immunohistochemistry. Results: B-vitamins produced an anti-hyperalgesia effect in the test period of 14 days. Expressions of nNOS in DRG neurons were also reduced by treatment with TPC. Conclusion: B vitamins can effectively alleviate the mechanical and thermal hyperalgesia induced by CCI, which may involve the inhibition of NO synthesis in the DRG neurons.