miR-122a对大鼠脊髓缺血/再灌注损伤后血-脊髓屏障的影响

Effects of miR-122a on blood-spinal cord barrier after spinal cord ischemia-reperfusion injury in rats

目的探讨miR-122a对脊髓缺血/再灌注损伤后血-脊髓屏障的影响。方法 SD大鼠36只,随机分为3组:假手术组(S组)、对照组(C组)、miR-122a反义寡核苷酸(miR-122a antagomir)组(M组)。S组开胸游离主动脉弓,但不阻断;C组和M组开胸阻断主动脉弓14 min造成脊髓缺血/再灌注损伤。M组和C组脊髓缺血/再灌注损伤后,鞘内注射miR-122a antagomir或空白对照,每日1次,共3次。Real-time PCR测定损伤节段脊髓组织的miR-122a表达,Western blot测定脊髓组织中紧密连接蛋白occludin表达,伊文思蓝测定血-脊髓屏障通透性,Basso Beattie Bresnahan评分法评价神经运动功能。结果与S组比较,C组miR-122a表达增加,occludin表达减少,血-脊髓屏障通透性增加,神经运动功能评分降低(P<0.05)。与C组比较,M组miR-122a表达降低,occludin表达增加,血-脊髓屏障通透性降低,神经运动功能评分增加(P<0.05)。结论 miR-122a参与调控脊髓缺血/再灌注损伤后occludin表达,影响血-脊髓屏障通透性。

Aim To investigate the effects of miR-122a on blood-spinal cord barrier after spinal cord ischemia-reperfusion injury in rats.Methods Thirty-six SD rats were randomly divided into three groups：group of sham（S group）, group of control（C group）and group of miR-122a antagomir（M group）.Rats in S group were subjected to exposure of aorta arch but without occlusion.Spinal ischemia-reperfusion injury was induced by clamping the aorta arch for 14 min in C group and M group.Rats in M group and C group were intrathecally injected with miR-122a antagomir or antagomir control daily for three times after injury.The miR-122a expression in injured spinal cord tissue was detected by real-time PCR.The occludin expression in injured spinal cord tissue was detected by Western blot.The permeability of blood-spinal cord barrier was examined using evans blue as a vascular tracer.The neurological motor function was evaluated by Basso Beattie Bresnahan score.Results Compared with S group, the expression of miR-122a was increased, the expression of occludin was decreased, the permeability of blood-spinal cord barrier was increased, and neurological motor function score was decreased significantly in C group（P〈0.05）.Compared with C group, the expression of miR-122a was decreased, the expression of occludin was increased, the permeability of blood-spinal cord barrier was decreased, and neurological motor function score was increased significantly in M group（P〈0.05）.Conclusion miR-122a can regulate the expression of occludin and change the permeability of blood-spinal cord barrier.