白介素-1受体拮抗剂对大鼠急性脊髓损伤后神经细胞凋亡和caspase-3表达的影响

Effect of interleukin-1 receptor antagonist on neuronal apoptosis and the expression of caspase-3 after spinal cord injury

目的:观察白介素-1受体拮抗剂(IL-1Ra)对脊髓损伤(SCI)后继发性神经细胞凋亡和caspase-3表达的影响。方法:60只SD大鼠,随机分为假手术组、脊髓损伤组、IL-1Ra治疗组和生理盐水对照组,每组15只。采用Allen′s法建立大鼠急性SCI动物模型,IL-1Ra治疗组和生理盐水对照组于SCI后立即硬膜下腔内分别注射IL-1Ra(10μg/10μl)和等量生理盐水,于伤后24h以损伤为中心(假手术组取相应部位),切取长约8mm脊髓组织,用蛋白印迹法和免疫组化染色法检测caspase-3表达的变化;采用实时定量PCR法检测caspase-3mRNA的表达情况;用原位末端标记法(TUNEL)检测SCI后神经细胞凋亡情况。结果:SCI后24h,SCI组与假手术组比较受损伤的脊髓组织中caspase-3mRNA和蛋白表达水平均显著升高(P<0.05),且TUNEL阳性细胞明显增多(P<0.01);IL-1Ra治疗组大鼠受损伤节段脊髓组织caspase-3表达及TUNEL阳性细胞数较生理盐水对照组)均明显减少(P<0.01)。结论:IL-1Ra治疗可减少急性SCI后脊髓组织中caspase-3的表达和神经细胞凋亡的发生。

Objective：To investigate the effect of interleukin-1 receptor antagonist（IL-1Ra） on neuronal cell apoptosis and the expression of caspase-3 after spinal cord injury in rats.Method：60 SD rats were divided into 4 groups：SCI group,IL-1Ra group,Normal saline group,and sham-operated group.The SCI model was introduced using the Allen＇ method（25g-cm）,and rats in IL-1Ra group were treated with IL-1Ra after SCI.Recombinant rat IL-lra （10μg/10μL） were given intrathecally immediately after the injury.24h after injury,an 8mm of spinal cord segment was dissected longitudinally from the lesion site at each group.The expression of caspase-3 was detected using western blot and immunohistochemistry method.The expression of caspase-3 mRNA was detected by RT-PCR.Apoptosis neuron was marked with Terminal deoxynucleotidyl transferasemidiated deoxyuredine triphosphate-biotin nick end labeling（TUNEL） staining.Result：Western Blots and RTPCR showed,comparing with sham-operated group,the expression of caspase-3 was markedly increased in the injured spinal cord at 24h after injury （P〈0.05）.There were more TUNEL-positive cells in SCI group than in sham-operated group in the lesioned area at 24h after SCI.Compafing with normal saline group,injecting IL- 1Ra intrathecally significantly reduced the expression of caspase-3 （P〈0.01）,and decreased the number of TUNEL-positive cells （P〈0.01）.Conclusion：IL-1Ra may inhibit the expression of Caspase-3,and reduce neuronal cell apoptosis after SCI.