褪黑素对大鼠急性脊髓损伤后HO-1因子表达的影响

摘要

目的 研究褪黑素(MT)对大鼠急性脊髓损伤(SCI)后血红素氧合酶(HO-1)表达的影响,探讨MT对SCI的作用机制.方法 选取108只成年SD大鼠,随机分为3组:对照组、损伤组、MT组.对照组仅行椎板切除,暴露T11~T12节段,不损伤脊髓神经.损伤组和MT组用改良的Allen's法建立T11~T12 SCI模型,并分别在SCI后10 min腹腔注射MT溶剂和MT制剂.各组于术后6、12、24 h随机选取12只大鼠处死,取T11~T12节段脊髓标本.其中6个标本液氮保存,以备检测HO-1 mRNA的表达水平,另外6个标本甲醛固定,以备HE染色和免疫荧光切片,观察SCI及修复情况.结果 术后各时间点大鼠脊髓的HO-1 mRNA水平比较:MT组最高,损伤组次之,对照组最低,在12 h和24 h时间点上各组间差异有统计学意义(P<0.05).HE染色切片观察SCI程度:对照组最轻,MT组次之,损伤组最重.免疫荧光显示:MT组HO-1表达最多,损伤组次之,对照组最少.结论 MT能在大鼠急性SCI后促进HO-1表达,并减轻损伤脊髓的炎性反应.%Objective To study the effects of melatonin (MT) on the expression of heme oxygenase (HO-1) after acute spinal cord injury (SCI) in rats, and explore the effects of MT on spinal cord injury.Methods A total of 108 adult SD rats were selected and randomly divided into three groups: control group, injury group and MT group.Lamina was removed in control group.Consequencely, T11-T12 segment was exposed without spinal nerves damage.The T11-T12 acute SCI models in injury group and MT group were established by use of the modified Allen's method.At 10 min after SCI, MT and MT preparations were intraperitoneally injected in injury group and MT group, respectively.In every groups, 12 rats were randomly sacrificed at 6 h, 12 h and 24 h after operation, then T11-T12 spinal cord specimens were collected.The 6 specimens were stored in liquid nitrogen for dectecting the expression level of HO-1 mRNA, while the other 6 specimens were fixed with formalin for HE staining and immunofluorescence sections to observe the spinal cord injury and repair.Results At 6 h, 12 h and 24 h, the levels of HO-1 mRNA in MT group were highest, those of which in control group were lowest.Significant differences (P<0.05) in HO-1 mRNA level at 12 h and 24 h were found among control group, injury group and MT group.In terms of SCI degree, control group was lightest, followed by MT control and injury group.In addition, immunofluorescence showed that HO-1 expression in MT group was the most, that of which in control group was the least.Conclusion MT could promote the expression of HO-1 after acute SCI in rats, and reduce the inflammatory response of injured spinal cord.