不同浓度丁卡因或罗哌卡因对大鼠臂丛神经的毒性

Neurotoxic effects of different concentrations of tetracaine and ropivacaine on brachial plexus nerve in rats

目的探讨不同浓度丁卡因和罗哌卡因对大鼠臂丛神经的毒性。方法成年雄性SD大鼠48只，体重410～430g,采用随机数字表法，将其随机分为8组（n=6）：生理盐水组（NS组）、0．25％、0．50％、1．00％丁卡因组（T1-3组）、0．25％、0．50％、1．00％、2．00％罗哌卡因组（R1-4组）。随机选取一侧腋鞘，Ns组注射生理盐水1．0ml，T。组分别注射0．25％、0．50％、1．00％丁卡因0．5ml，R1-3组分别注射0．25％、0．50％、1．00％罗哌卡因1．0ml，凡组注射2．00％罗哌卡因0．5ml。另一侧腋鞘作为对照。于注药后5d时检测臂丛神经复合动作电位及其传导速度（NCV），并采用光镜和透射电镜观察臂丛神经的病理学结果。结果与对照侧和NS组比较，T2-3组和R3-4组臂丛神经复合动作电位降低，NCV减慢（P〈0．05）；T1组、T2组和T3组臂丛神经复合动作电位依次降低，NCV依次减慢（P〈0．05）；与R1-3组比较，凡组臂丛神经复合动作电位降低，NCV减慢（P〈0．05）。病理学改变：L组、B组和Rd组神经束膜明显水肿，髓鞘板层分离、断裂、重度脱髓鞘，轴突萎缩；R3组为“脱髓鞘”现象，髓鞘板层分离、断裂、重度脱髓鞘，轴突萎缩。结论0．50％、1．00％丁卡因和1．00％、2．00％罗哌卡因可导致大鼠臂丛神经产生病理性损伤，且损伤程度与其浓度有关。

Objective To investigate the neurotoxic effects of different concentrations of tetracaine and ropivacaine on the brachial plexus nerve in rats. Methods Forty-eight male Sprague-Dawley rats, weighing 410- 430 g, were randomly divided into 8 groups （ n = 6 each） ： normal saline group （group NS）, 0.25% , 0.50% and 1.00% tetracaine groups （groups %-3）, and 0.25%, 0.50%, 1.00% and 2.00% ropivacaine groups （groups R1-4 ）. The rats received injection of normal saline 1.0 ml, 0.25%, 0.50% and 1.00% tetracaine 0.5 ml, 0.25%, 0.50%, and 1.00% ropivacaine 1.0 ml and 2.00% ropivacaine 0.5 ml in groups NS, T,3 and R~.4 respectively through one side of the axillary sheath. The other side of the axillary sheath served as control side. Five days later, compound action potential and nerve conduction velocity （NCV） of the brachial plexus nerve were measured. The brachial plexus nerve was obtained as the specimen for microscopic examination with light and transmission electron microscope. Results Compared with the control side and group NS, the compound action potential and NCV of the brachial plexus nerve were significantly decreased in groups T2,3 and R3,4 （ P 〈 0.05）. The compound action potential and NCV of the brachial plexus nerve were gradually decreased with the increasing con- centrations of tetracaine in groups %-3 （ P 〈 0.05）. The compound action potential and NCV of the brachial plexus nerve were significantly decreased in group R4 as compared with groups R1-3 （ P 〈 0. 05）. The microscopic examination showed that the pathologic changes were more severe in groups T2,3 and R3,4 than those on the control side and than in group NS.Concluslon 0.50% and 1.00% tetracaine, and 1.00% and 2.00% ropivacaine can result in pathologic damage to the brachial plexus nerve in rats and the degree of damage is related to the concentration.