罗哌卡因致幼龄大鼠惊厥时对海马突触发育的影响

Effect of ropivacaine-induced convulsion on hippocampai synaptic development in neonatal rats

目的评价罗哌卡因致幼龄大鼠惊厥时对海马突触发育的影响。方法SD幼龄大鼠60只，21日龄，体重40～42g，采用随机数字表法，将其分为3组（n=20）：对照组（c）、单次惊厥组（SC组）和反复惊厥组（RC组）。C组腹腔注射生理盐水0．1ml；SC组单次腹腔注射0．5％罗哌卡因33．8mg／kg；RC组腹腔注射0．5％罗哌卡因33．8mg／kg，1次／d，连续5d；发生惊厥的大鼠纳入本研究。C组和sc组分别在惊厥后24h、3d、7d及大鼠60日龄时取5只大鼠；RC组分别在最后1次惊厥后24b、3d、7d及大鼠60日龄取5只大鼠，取海马，电镜下观察神经元超微结构，计数突触数量，测量突触间隙和突触后致密物厚度。结果与c组比较，sc组惊厥后24h、3d时突触数量减少，突触间隙增宽，惊厥后24h时突触后致密物厚度变薄，RC组惊厥后24h、3d、7d时突触数量减少，突触间隙增宽，突触后致密物厚度变薄（P〈0．05）；与SC组比较，RC组惊厥后24h、3d、7d时突触数量减少，突触间隙增宽，突触后致密物变薄（P〈0．05）；3组间60日龄时上述指标比较差异无统计学意义（P〉0．05）。sc组惊厥后24h、3d时神经元细胞核肿胀，线粒体出现水肿，可见线粒体嵴断裂和空泡，RC组惊厥后24h、3d、7d时上述改变更明显。结论罗哌卡因致幼龄大鼠惊厥时对海马突触发育无影响。

Objective To evaluate the effect of ropivaeaine-induced convulsion on hippocampal synaptie development in neonatal rats. Methods Sixty 21-day-old Sprague-Dawley neonatal rats, weighing 40-41 g, were randomly divided into 3 groups （n=20 each） using a random number table： control group （group C）, single convulsion group （group SC） , and recurrent convulsion group （group RC）. Normal saline 0.1 ml was intraperitoneally injected in group C. Group SC received single intraperitoneal injection of 0.5% ropivacainc 33.8 mg/kg. In group RC, 0.5% ropivaeaine 33.8 mg/kg was intraperitoneally injected once a day for 5 consecutive days. The rats developed convulsion were included in the study. Five rats were selected at 24 h, 3 days and 7 days after convulsion and at the age of 60 days in C and SC groups, and at 24 h, 3 days and 7 days after the last convulsion and at the age of 60 days in group RC, the rats were sac- rificed, and the hippocampus was removed for examination of the uhrastructure of neurons （with a electron microscope） and for determination of the number of synapses, synaptic space and thickness of synaptic density. Results Compared with group C, the number of synapses was significantly decreased, and the synaptic space was widened at 24 h and 3 days after convulsion l and the thickness of synaptic density was thinned at 24 h after convulsion in group SC, and the number of synapses was significantly decreased, and the synaptic space was widened, and the thickness of synaptic density was thinned at 24 h, 3 days and 7 days after convulsion in group RC （P〈0.05）. Compared with group SC, the number of synapses was sig- nificantly decreased, the synaptic space was widened, and the thickness of synaptic density was thinned at 24 h, 3 days and 7 days after convulsion in group RC （P〈0.05）. There was no significant difference in the parameters mentioned above at the age of 60 days between the three groups （P〉0.05）. Neurons exhibited nuclear swelling, mitochondria showed edema, and disrupted mitochondrial cristae and vacuoles were observed at 24 h and 3 days after convulsion, and these changes mentioned above were significantly attenuated at 24 h, 3 days and 7 days after convulsion. Conclusion Ropivacaine-induced convulsion exerts no effects on hippocampal synaptic development in neonatal rats.