rHMGB1预处理对脊髓损伤大鼠血脊髓屏障的影响及可能机制

Effect of rHMGB1 pretreatment on blood-spinal barrier in rats with spinal cord injury and its possible mechanism

目的 探讨rHMGB1预处理对脊髓损伤大鼠血脊髓屏障的影响及可能机制。方法 60只8周龄雌性SD大鼠,随机分为假手术组(Sham)、脊髓损伤组(SCI)和重组高迁移率族蛋白B1处理组(rHMGB1),每组20只。SCI后3 d,应用BBB评分评估运动功能恢复情况;测定脊髓组织含水量;伊文思蓝(EB)实验测定血脊髓屏障通透性变化;HE染色观察各组大鼠脊髓组织病理学改变;ELISA方法检测白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)的表达水平;Western blot方法检测水通道蛋白-4(AQP-4)、紧密连接蛋白ZO-1和Occludin的表达。结果 rHMGB1处理后,脊髓损伤大鼠BBB评分降低(P<0.05),脊髓组织含水量与EB染料含量升高(P<0.05),脊髓组织病理学改变加重,IL-1β、IL-6和TNF-α的表达水平升高(P<0.05),AQP-4蛋白的表达升高(P<0.05),而ZO-1和Occludin蛋白的表达降低(P<0.05)。结论 rHMGB1预处理能够加重SCI后血脊髓屏障的破坏,其机制可能与上调致炎因子的水平及抑制ZO-1和Occludin蛋白的表达相关。

Objective To investigate the effect of rHMGB1 pretreatment on blood-spinal barrier in rats with spinal cord injury and its possible mechanism.Methods Sixty 8-week-old female SD rats were randomly divided into sham operation group(Sham),SCI group(SCI)and recombinant high mobility group protein B1 pretreatment group(rHMGB1),with 20 rats in each group.Three days after SCI,BBB score was used to evaluate the recovery of motor function.The water content of the spinal cord was measured.Evans Blue(EB)assay was used to determine the changes of blood spinal barrier permeability.Histopathological changes of spinal cord were observed by HE staining.The expression levels of interleukin-1β(IL-1β),interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)were detected by ELISA,the expressions of aquaporin-4(AQP-4),tight junction proteins ZO-1 and Occludin were detected by Western blot.Results After rHMGB1pretreatment,BBB score of spinal cord injury rats was decreased(P<0.05).The water content of the spinal cord and content of EB was increased(P<0.05).The histopathological changes of spinal cordwere aggravated.The content of IL-1β,IL-6 and TNF-αwas increased(P<0.05).The expression of AQP-4 was increased,and the expression of ZO-1 and Occludin were decreased(P<0.05).Conclusion rHMGB1 pretreatment can aggravate the destruction of the blood-spinal barrier after SCI,and the mechanism may be related to the up-regulation of inflammatory factors and the inhibition of ZO-1 and Occludin protein expression.