七叶皂甙钠对坐骨神经结扎术后大鼠热痛觉及脊髓神经细胞凋亡的影响

目的探讨七叶皂甙钠对坐骨神经结扎术后大鼠热痛觉及脊髓神经细胞凋亡的影响。方法90只SD大鼠随机分为正常对照组、坐骨神经慢性压迫损伤(CCI)模型组(CCI组)和药物治疗组(药物组),每组30只大鼠。采用坐骨神经中段结扎法制作大鼠CCI模型。药物组大鼠术后给予腹腔注射0.1%七叶皂甙钠5 mg/(kg.d)治疗,CCI组给予等量生理盐水替代。各组于术前1 d取5只大鼠测定热痛觉,于术后8h、1 d、3 d、7 d、14 d及21 d时分别取5只大鼠测定热痛觉后处死。分别应用TUNEL法及免疫组化染色法检测大鼠相应损伤段脊髓组织中凋亡神经细胞数及肿瘤坏死因子-α(TNF-α)的表达。结果各组大鼠术前1 d时热痛觉的比较差异无统计学意义。CCI组及药物组大鼠术后热痛觉均较正常对照组更敏感(均P<0.05);药物组大鼠术后热痛觉较CCI组迟钝(均P<0.05)。CCI组及药物组大鼠术后各时间点脊髓组织中凋亡细胞数均明显多于正常对照组(均P<0.05);药物组大鼠术后各时间点脊髓组织中凋亡细胞数均明显少于CCI组(均P<0.05)。CCI组大鼠术后8 h～14 d,药物组术后8 h～7 d脊髓组织TNF-α的表达均明显高于正常对照组(均P<0.05);两组TNF-α的表达均于术后8 h起逐渐增高,至术后3 d时达最高,其后逐渐减少(均P<0.05);并分别于术后21 d及14 d时降至正常对照组水平。结论结扎大鼠坐骨神经可产生神经病理性疼痛,并可诱发脊髓神经细胞凋亡。七叶皂甙钠能缓解坐骨神经结扎术后大鼠热痛觉增敏,这可能与其降低TNF-α在脊髓后角的表达及抑制神经细胞的凋亡有关。

Effects of Sodium aescinate on heat pain and spinal neural apoptosis in rats after sciatic nerve ligation

Objective To observe the effects of Sodium aescinate on heat pain and spinal neural apoptosis in rats after sciatic nerve ligation.Methods Ninty SD rats were randomly divided into normal control group(NC group),chronic constriction injury(CCI) model group(CCI group) and therapy group,with 30 rats in each group.CCI models were made by sciatic nerve middle part ligation method.Rats in therapy group were given 0.1% sodium aescinate 5 mg/(kg·d) after operation,while the rats in CCI group were treated with equivalent normal salinet.The heat pain of 5 rats in each group were tested at 1 d before operation,and 5 rats in each group were sacrificed after the test of heat pain at 8 h,1 d,3 d,7 d,14 d and 21 d after operation,respectively.The number of neuronal apoptosis in spinal tissue at the segment of relevant injury and the expression of tumor necrosis factor-α(TNF-α) were detected by TUNEL method and immunohistochemistry method,respectively.Results There was no significant difference of heat pain at 1 d before operation between each groups.The heat pain in CCI group and therapy group was more sensitive than that in NC group(all P<0.05).The heat pain in therapy group was less sensitive than that in CCI group(all P<0.05).The quantity of neuronal apoptosis in CCI group and therapy group was significantly more than that in NC group(all P<0.05);and which in therapy group was significantly less than that in CCI group(all P<0.05).The expression of TNF-α in CCI group at 8 h-14 d after operation and therapy group at 8 h-7 d after operation were significantly higher than that in NC group(all P<0.05);which began to increase at 8 h after operation,and reached the highest at 3 d after operation,then gradually decreased(all P<0.05);and which reached the level of NC group at 21 d and 14 dafter operation,respectively.Conclusions Sciatic nerve ligation can lead neuropathic pain and spinal neuronal apoptosis.Sodium aescinate can relief the enhancement of heat pain of rats after the sciatic nerve ligation,which may be related with its effects of reducing the expression of TNF-α at spinal dorsal horn and inhibiting the neuronal apoptosis.