大剂量甲基强的松龙不能通过溶酶体途径保护损伤早期的脊髓神经（英文）

High-dose methylprednisolone cannot protect against early spinal cord injury through lysosome apoptosis pathway

背景:Cathepsis家族是否参与脊髓损伤早期的病理过程以及大剂量甲基强的松龙是否通过溶酶体机制发挥神经保护作用目前尚不清楚。目的:检测Cathepsin基因家族在脊髓损伤早期的表达和大剂量甲基强的松龙干预后的变化,明确大剂量甲基强的松龙是否通过调节溶酶体凋亡途径发挥神经保护作用。方法:9只日本大耳兔随机分为3组:模型组和药物组进行椎板切除后采用Allen法建立急性脊髓损伤模型,药物组在造模后2h按人-兔等效剂量给予大剂量甲基强的松龙冲击治疗,对照组仅进行椎板切除。造模后8h处死实验动物,取脊髓组织,采用Trizol法提取总RNA,用9张Agilent兔子全基因4*44K芯片进行检测。采用GeneSpring 10.0软件,以P<0.05且倍数变化(FC)≥2筛选出差异表达基因。结果与结论:成功建立脊髓损伤的动物模型并获得相应的组织标本。9组标本总RNA的质量均能满足基因芯片检测要求。基因芯片结果显示:在10个Cathepsin基因家族成员中,仅Cathepsin Z和proathepsin E在创伤后呈现差异性表达,Cathepsin C、D、F、K、L、S和W表达均无差异。甲基强的松龙冲击治疗后Cathepsin家族基因表达均无差异(在药物组与模型组的比较)。提示Cathepsin Z和E参与了脊髓损伤早期凋亡过程,但大剂量甲基强的松龙并不能通过溶酶体凋亡途径发挥神经保护作用。

BACKGROUND： It is not clear whether the Cathepsis family is involved in the pathological process of early spinal cord injury and whether high-dose methylprednisolone plays neuroprotective effect through lysosome apoptosis pathway. OBJECTIVE： To explore the expression and change of genes Cathepsin family in early spinal cord injury and to identify if high-dose methylpradnisolone plays neuroprotective effect by the lysosome apoptosis pathway. METHODS： Nine Japanese rabbits were randomly divided into three groups, the rabbits in the model group and drug treatment group were treated with laminectomy, and then the rabbits were used to establish the acute spinal cord injury model with Allen falling strike method. The rabbits in the drug treatment group were treated with human equivalent dose flushing-dose methylprednisolone at 2 hours after acute spinal cord injury. The rabbits in the control group were treated with laminectomy. All rabbits were killed at 8 hours after acute spinal cord injury, and then the damaged spinal cord tissues were obtained carefully. Total RNA was extracted from above nine samples with Trizol One-step method to undergo the examination of the gene expression profile by using Agilent Rabbit Oligo Micrearray （4×44K） respectively. GeneSpring 11.0 software was then used to filter potential candidate genes, and only genes with P values ≤0.01 and fold change≥2 were retained for further analysis. RESULTS AND CONCLUSION： The spinal cord injury models were successfully set up and the corresponding tissue specimens were obtained. Acquired nine subsample of total RNA were qualified for microarray examination. The results of microarray examination showed that among the 10 genes of Cathepsin family, only Cathepsin Z and Procathepsin E showed significant different expression. All of Cathepsin family genes of Cathepsin C, D, F, K, L, S and W did not showed significant different expression. There were no significant differences of Cathepsin family genes expressions between drug treatment group and model group after treated with methylprednisolone. Gene Cathepsin Z and Procathepsin E took part in the apoptosis of spinal cord injury at acute phase, but high-close methylprednisolone cannot play neuropretective effect by the lysosome apoptosis pathway.