[大鼠连续鞘内注射罗哌卡因后血浆中髓鞘碱性蛋白浓度及脊髓超微结构的改变]

[Alterations of myelin basic protein concentration in the plasma and ultrastructure in the spinal cord after continuous intrathecal ropivacaine injection in rats].

作者信息

Yang Sheng-Hui, Guo Qu-Lian, Wang Yi-Chun

机构信息

Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha 410008, China.

出版信息

Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2008 Jun;33(6):527-32.

PMID:18600002

Abstract

OBJECTIVE

To explore the alterations of serum of myelin basic protein (MBP) concentration in the plasma and ultrastructure in the spinal cord after continuous intrathecal injection of different ropivacaine concentrations in rats.

METHODS

Ninety-six male Sprague-Dawley rats weighing 220 to approximately 280 g were randomly divided into a control group (Group N), Group R(1), R(2) and R(3) (24 rats in each group). Each group was subdivided into 4 subgroups (6 rats in each subgroup). According to the method of Yaksh's, a polyurethane microspinal catheter was inserted into the lumbar subarachnoid space in which 8 cm segment was left. Rats in each group were continuously received 40 microL of intrathecal injection of normal saline(Group N), 0.5%, 0.75%, and 1.0% ropivacaine (Group R(1),R(2),R(3)), 3 times every 1.5 hours. Blood (0.5 mL) was drawn from the femoral artery to determine serum concentrations of MBP at the detecting time T(0)(before inserted pipe)and T(1)(before the first intrathecal injection); for the subgroups, the examining time was at T(2), T(3), T(4) and T(5)(6, 12, 24 and 48 h respectively after the last time intrathecal administration). After blood was drawn, the rats in each subgroups were decapitated and the spinal cord of L(1-2) intumescentia lumbalis were immediately removed for electronic microscopic examination.

RESULTS

MBP levels were comparatively steady in Group N, R(1) and R(2), while there was statistical difference between Group R(3) and Group N, R(1),R(2),and R(3) (P<0.05). MBP level of Group R(3) was significantly higher at T(2),T(3),T(4) and T(5) than that at T(0)(P<0.01). The ultrastructural changes of the spinal cord in Group R(3) were pycnosis of most neurons, dilation of most rough endoplasmic reticulum, and vague structure of mitochondria and endocytoplasmic reticulum. A few neurons were completely de-generated losing the normal structure, with vacuole degeneration of crista mitochondriales or even partial loss.

CONCLUSION

The spinal cord ultrastructure is selectively vulnerable after intrathecal 1.0% ropivacaine injection, which may be one of the important pathophysiological bases for local anesthetic neurotoxicity. MBP may serve as a sensitive and specific indicator of spinal cord damage after intra-thecal administration of ropivacaine.

摘要

目的

探讨大鼠连续鞘内注射不同浓度罗哌卡因后血浆中髓鞘碱性蛋白（MBP）浓度及脊髓超微结构的变化。

方法

将96只体重220～280 g的雄性Sprague-Dawley大鼠随机分为对照组（N组）、R(1)组、R(2)组和R(3)组，每组24只。每组再分为4个亚组，每组6只。按照Yaksh的方法，将聚氨酯微脊髓导管插入腰蛛网膜下腔，留置8 cm段。各组大鼠连续鞘内注射40 μL生理盐水（N组）、0.5%、0.75%和1.0%罗哌卡因（R(1)组、R(2)组、R(3)组），每1.5小时1次，共3次。于检测时间T(0)（置管前）和T(1)（首次鞘内注射前）从股动脉取血0.5 mL，测定血浆MBP浓度；各亚组于末次鞘内给药后6、12、24和48 h（即T(2)、T(3)、T(4)和T(5)）检测。取血后，将各亚组大鼠断头，立即取出腰膨大L(1-2)节段脊髓进行电镜检查。

结果

N组、R(1)组和R(2)组MBP水平相对稳定，R(3)组与N组、R(1)组、R(2)组比较差异有统计学意义（P<0.05）。R(3)组在T(2)、T(3)、T(4)和T(5)时MBP水平显著高于T(0)时（P<0.01）。R(3)组脊髓超微结构改变为多数神经元固缩，多数粗面内质网扩张，线粒体和内质网结构模糊。少数神经元完全退变，失去正常结构，线粒体嵴空泡变性甚至部分丢失。