脊髓损伤后炎症性细胞因子表达的变化及甲基强的松龙的影响

Expression of pro-inflammatory cytokine mRNA after spinal cord injury and effect of the methylprednisolone in rats

目的 观察大鼠脊髓损伤(SCI)后,甲基强的松龙(MP)对炎症性细胞因子白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α) mRNA表达及运动功能恢复的影响。方法 采用改良 Allen氏法建立大鼠脊髓(T9、T10)中度损伤模型,56只SD大鼠随机分为假手术组(n=4)、SCI组(n=24)、生理盐水组(n=14)和 MP组(n=14),分别于损伤后 1 h、4 h、12 h、24 h、72 h和7 d取材,利用半定量RT PCR方法观察损伤段脊髓组织中上述 3 种细胞因子 mRNA表达的变化规律;于 SCI后30 min经尾静脉给予MP(30 mg/kg),利用半定量RT-PCR方法检测 SCI后 4 h时 MP对各炎症性细胞因子 mRNA表达的影响;利用BBB评分检测MP对大鼠SCI后运动功能恢复的影响。结果 假手术组动物脊髓组织中炎症性细胞因子mRNA仅有微弱表达。SCI后1h,各炎症性细胞因子mRNA表达明显升高,其中 IL-1β,IL-6表达于损伤后 12 h达峰值,TNF-α于损伤后 4 h达峰值,至损伤后72 h仍高于假手术组( P <0.05)。SCI后4 h时,MP组大鼠 IL-1β和TNF-αmRNA的表达明显受到抑制,但MP并未对运动功能的恢复产生有益的影响。结论 MP可明显抑制SCI后的炎症反应。

ObjectiveTo investigate the expression of pro inflammatory cytokine mRNA including interleukin 1β (IL 1β), interleukin 6 (IL 6) and tumor necrosis factor α (TNF α) after spinal cord injury (SCI), and the effect of methylprednisolone (MP) on the expression of the cytokine and neurological outcome after SCI in rats.MethodsA moderate SCI model was made with SD rats according to modified Allen's method. 56 SD rats were divided randomly into the sham group (n=4), SCI group (n=24), saline group (n=14) and MP group (n=14, MP 30 mg/kg injected throuh tail vein 30 min after injury). Samples of injured spinal cord were taken at 1 h, 4 h, 12 h, 24 h, 72 h and 7 day after SCI. The mRNA expressions of IL 1β, IL 6 and TNF α in the spinal cord of rats were measured by semi quantitative RT PCR at 1 h, 4 h, 12 h, 24 h, 72 h and 7 d post injury, and 4 h post operation in the control group. The effect of MP (30 mg/kg, iv, within 30 minutes post injury) on the expression of cytokine at 4 h post injury was tested with RT PCR. The neurological outcome of rats was evaluated with BBB scores.ResultsThe expression of the cytokine mRNA was little in the sham group and significantly increased in injured groups with IL 1β at 12 h, TNF α at 4 h reaching peak after injury, and higher than that in sham group until 72 h ( P<0.05). While, the expressions of IL 1β and TNF α mRNA were inhibited obviously in MP group at 4 h after injury, but MP had no effect on the neurological outcomes.ConclusionMP can inhibit inflammatory reaction obviously. [