鞘内注射罗哌卡因与布比卡因对大鼠的脊髓神经毒性

Neurotoxic effects of intrathecal ropivacaine and bupivacaine on the spinal cord in rats

目的评价鞘内注射罗哌卡因与布比卡因对大鼠的脊髓神经毒性。方法清洁级雌性SD大鼠，体重240～330g，取鞘内置管成功的大鼠54只，随机分为3组（n=18）：NS组鞘内注射生理盐水30μl；BU组和RO组分别鞘内注射2％布比卡因20μl和2．7％罗哌卡因20阻，随后注射10μl生理盐水冲洗导管。于鞘内注药前、注药后10、20、30、60和120min时（T1～6）行双后肢运动阻滞评分；于鞘内注药后第4天取腰段脊髓组织，观察病理学结果并行损伤评分。结果与NS组比较，BU组L2-5，时、RO组T2～4时大鼠双后肢运动阻滞评分升高，两组脊髓组织损伤评分升高（P〈0．05），脊髓组织病理学损伤较重；与T2时比较，BU组和RO组其余各时点双后肢运动阻滞评分降低（P〈0．05），两组己时差异无统计学意义（P〉0．05）；与BU组比较，RO组脊髓组织损伤评分升高（P〈0．05），脊髓组织病理学损伤较重。结论鞘内注射2．7％罗哌卡因对大鼠的脊髓神经毒性强于2％布比卡因。

Objective To compare the neurotoxic effects of intrathecal ropivacaine and bupivacaine on the spinal cord in rats. Methods Female SD rats weighing 240-330 g were used in this study. Catheters （ PE 10 tubing） were inserted through an incision in the eisternal membrane and advanced caudad until the tip of the catheter reached the lumbar spinal level according to the technique described by Yaksh and Rudy. Fifty-four successfully catheterized rats were randomly assigned to one of 3 groups （ n = 18 each） ： group Ⅰ received normal saline 30 μl IT （NS） ; groupⅡ received 2% bupivacaine 20 μl IT （BU） and group Ⅲ 2.7% ropivacaine 20 μl IT （RO）. Degree of motor block was assessed and scored （0 = no block, 2 = inability to flex the hind limb） before （T1 , baseline） and at 10, 20, 30, 60 and 120 min （T2-6 ） after IT injection. On the 4th day after IT injection specimens were obtained from lumbar spinal cord for microscopic examination. Results The motor block score was significantly higher in group BU and RO than in group NS （ P 〈 0.05）, and the tissue damage was severe in group BU and RO. The motor block scores were significantly higher at T2 than at T3-6 in both group BU and RO（ P 〈 0.05） . There was no significant difference in motor block score at T2 between groups BU and RO but the motor block scores were significantly lower at T3-5 in group RO than in group BU （ P 〈 0.05 ） . The tissue damage was severer in group RO than in group BU （ P 〈 0.05）. Conclusion Intrathecal 2.7 % ropivacaine is more toxic to the spinal cord than intrathecal 2% bupivacaine in rats.