【摘要】 目的观察硬膜外不同浓度辣椒辣素(CAP)对兔痛阈、神经功能和脊髓神经元结构的影响。方法健康新西兰雄性白兔36只,随机分为4组:对照组、C1、C2、C3组,每组9只。L6,7间隙硬膜外穿刺置管,C1、C2、C3组分别注入0．1％、0．25％、0．5％CAP 1 ml,对照组注入0．9生理盐水1 ml。观察后肢热痛阈和神经功能改变,注药后24 h,每组处死3只家兔,在光镜、电镜下观察L6,7脊髓神经元的病理改变。结果与对照组相比,注药后C1、C2、C3组痛阈延长(P<0．05),随CAP浓度增加,痛阈延长时间增加,而神经功能评分下降。光镜、电镜下显示C2组神经元发生可逆性改变,C3组发生不可逆性改变。结论兔硬膜外注入CAP可延长痛阈,高浓度CAP可导致神经功能和脊髓神经元结构损害。更多还原

【Abstract】 Objective To evaluate the effects of different doses of epidural capsaicin on pain threshold, neurological function and spinal neurons.Methods Thirty-six male New Zealand white rabbits weighing 2.5-3.0 kg were randomly divided into 4 groups (n = 9 each): control group and 3 capsaicin groups (Cap 1, 2, 3). The animals were anesthetized with 10% chloral hydrate 50-75 mg·kg-1 i.v. . An intrathecal catheter was inserted at L6,7 interspace and correct placement was confirmed by outflow of CSF. 1 ml of 0.1 % ( Cap1) , 0.25 % ( Cap2 ) or 0.5% (Cap3 ) capsaicin was injected intrathecally 24 h after IT catheter was placed. Threshold to noxious thermal stimuli was measured and gait of the hind limbs were assessed using Johnson score (5 = normal, 0 = completely paralyzed), before and 1, 3, 7, 10, 15, 20, 25, 30 days after IT injection. On the 2nd day after IT injection 3 animals were killed in each group and the lumbar segment of spinal cord (L6,7) was immediately removed for light and electron microscopic examination. Results The threshold to noxious thermal stimuli was significantly higher in the 3 capsaicin groups than in control group ( P < 0.05) . The duration of analgesia was significantly longer in group Cap 2, 3 than in group Cap1 . The neurological function of hind limbs was significantly impaired at 5, 15 min after IT injection but returned to normal within 30 min. The neuronal damage induced by capsaicin was concentration-dependent. Conclusion Epidural capsaicin can increase pain threshold. The duration of analgesia, neurological function deficit and neuronal damage induced by epidural capsaicin are dose-dependent.更多还原