脊髓全横断模型大鼠损伤区白细胞介素17的表达

Interleukin-17 expression in the injured site of a rat model of complete spinal cord transection

背景:现阶段,针对已知的炎性递质的干预措施对于减轻脊髓继发损伤的效果局限。白细胞介素17是重要的促炎性细胞因子,在中枢神经系统疾病发病机制中的作用正逐渐受到关注。目的:观察急性脊髓损伤模型大鼠白细胞介素17 mRNA和蛋白表达的变化规律。方法:健康雄性SD大鼠随机分为2组:模型组制作大鼠脊髓完全横断模型,假手术组仅剪开硬脊膜而不伤及脊髓实质。开放后测定肢运动功能评分观察急性脊髓损伤对大鼠运动功能的影响,苏木精-伊红染色观察脊髓损伤后不同时间点组织病理学改变,实时荧光定量PCR、Western blot分别检测各组大鼠脊髓损伤后不同时间点白细胞介素17 mRNA和蛋白水平表达变化。结果与结论:开放后肢运动功能评分结果:假手术组大鼠BBB评分均为20-21分,脊髓损伤1,2 d大鼠BBB评分均为0分,损伤后7 d BBB评分为0-3分(P<0.05)。苏木精-伊红染色结果:与假手术组相比,脊髓损伤6 h后,炎性细胞浸润,神经元和胶质细胞肿胀,神经元突起减少;脊髓损伤12 h后,灰质、白质组织结构疏松、空泡化;脊髓损伤后7 d,胶质细胞增生,组织纤维化明显。RT-qPCR结果显示:白细胞介素17 mNA于脊髓损伤后3 h出现,并于6 h表达出现高峰(P<0.01),随后表达减少,7 d后表达接近假手术组水平。Western blot结果显示:脊髓损伤6 h后,白细胞介素17表达开始升高,并于损伤后12 h出现高峰(P<0.05),随后表达减少,至伤后7 d表达接近假手术组水平。结果可见脊髓损伤12 h后组织损伤表现最严重,并与白细胞介素17表达改变存在时间的一致性,推断白细胞介素17可能参与了脊髓继发性炎症反应过程。

BACKGROUND：Intervention using known inflammatory transmitters has limitations on relieving secondary spinal cord injury. Interleukin-17 is an important proinflammatory cytokine, and is gradual y paid attention in the pathogenesis of central nervous system diseases. OBJECTIVE：To investigate the altered rule of interleukin-17 mRNA and protein in a rat model of acute spinal cord injury. METHODS：Healthy male Sprague-Dawley rats were randomly assigned to two groups. In the model group, rats were made into complete spinal cord transaction models. In the sham surgery group, only spinal dura mater was opened, but parenchyma was not injured. Basso, Beattie, Bresnahan locomotor rating scale was used to observe the effects of acute spinal cord injury on limb motor function of rats. Hematoxylin-eosin staining was used to observe histopathological changes at various time points after spinal cord injury. Real-time fluorescence quantitative PCR and western blotting were used to detect interleukin-17 mRNA and protein levels in each group at various time points after spinal cord injury. RESULTS AND CONCLUSION：Basso, Beattie, Bresnahan locomotor rating scale：Basso, Beattie, Bresnahan＆amp;nbsp;scores were 20 to 21 in the sham surgery group. Basso, Beattie, Bresnahan scores were 0 at 1 and 2 days after spinal cord injury. At 7 days, Basso, Beattie, Bresnahan scores were 0 to 3 （P〈0.05）. Hematoxylin-eosin staining results revealed that compared with the sham surgery group, inflammatory cel infiltration, neuronal and glial cel swel ing, and a reduced number of neuronal processes were observed at 6 hours after spinal cord injury. Gray matter and white matter were loose and vacuolated at 12 hours. Gliocyte proliferation and tissue fibrosis were apparent at 7 days. Real-time PCR results demonstrated that interleukin-17 mRNA appeared at 3 hours, and peaked at 6 hours （P〈0.01）, and then decreased. Interleukin-17 mRNA levels were similar to the sham surgery group at 7 days. Western blotting results revealed that interleukin-17 expression began to increase at 6 hours and peaked at 12 hours （P〈0.05）, and then reduced, and reached the levels in the sham surgery group at 7 days. Results indicated that tissue injury was most severe at 12 hours, and showed a time consistency with interleukin-17 expression. It is inferred that interleukin-17 is possibly involved in the process of secondary inflammatory reaction of spinal cord.