细胞自噬在脂氧素A4治疗大鼠脊髓缺血再灌注损伤中的作用

Effects of autophagy of lipoxin A4 on spinal cord ischemia-reperfusion injury in rats

目的脂氧素A4(LXA4)在大鼠脊髓缺血再灌注损伤中已被证实具有良好的保护作用,细胞自噬是否是其保护作用机制之一仍不明确。文章拟讨论细胞自噬在LXA4治疗大鼠脊髓缺血再灌注损伤中的作用。方法48只大鼠以随机数字表法分为LXA4组、缺血再灌注组、假手术组,每组16只,假手术组仅暴露腹主动脉,其他两组构建脊髓缺血再灌注损伤模型,LXA4组:在关腹后30 min脊髓鞘内注射10μL LXA4(300 pmol);缺血再灌注组:在关腹后30 min脊髓鞘内注射等渗盐水(0.1 mL/kg);假手术组:不注射药物。3组大鼠分别于再灌注24 h后颈椎脱臼法处死,处死后取出腰段脊髓。LC3B荧光染色法对3组大鼠的脊髓组织进行染色并计数,Western blot检测LC3-Ⅱ/LC3-Ⅰ、γ-氨基丁酸受体A相关蛋白(GABARAP)的表达。结果假手术组LC3B阳性细胞较少,缺血再灌注组(399.80±18.46)和LXA4组(240.80±12.76)的LC3B阳性细胞数较假手术组(73.40±19.42)明显升高(P<0.05),LXA4组较缺血再灌注组阳性细胞数明显减少(P<0.05)。缺血再灌注组及LXA4组大鼠的LC3-Ⅱ/LC3-Ⅰ、GABARAP的表达较对照组明显增高(P<0.05);与缺血再灌注组比较,LXA4组脊髓组织中LC3-Ⅱ/LC3-Ⅰ明显下降(P<0.05)。结论当SCII发生后,激活了细胞自噬,说明细胞自噬参与了SCII发生的过程;给予LXA4后,细胞自噬被抑制,脊髓缺血再灌注损伤缓解。

Objective Lipoxin A4(LXA4)has been proved to have a good protective effect on spinal cord ischemia-reperfu-sion injury in rats,but whether autophagy is one of the protective mechanisms remains unclear.This study aims to investigate the ef-fects of lipoxin A4 on rat spinal cord ischemia-reperfusion injury.Methods 48 rats were randomly divided into LXA4 group,isch-emia-reperfusion group(SCII group)and sham group with 16 rats in each,and the models of each group were built accordingly.The rats in LXA4 group received intrathecal injection of 10μl LXA4(300 pmol)30 minutes after clamping the abdominal aorta.Three groups of rats were sacrificed by cervical dislocation 24 hours after reperfu-sion and the apoptosis-positive cells were then obtained.The spinal cord tissues of three groups of rats were stained and counted by LC3 B fluorescence staining,and the expressions of LC3-II/LC3-I and GAB-ARAP protein were detected by Western blot.Results There were few LC3 B positive cells in the sham group.Compared to those in the sham group(73.40±19.42),the number of LC3 B positive cells in SCII group(399.80±18.46)and LXA4 group(240.80±12.76)significantly increased(P<0.05),and the number in LXA4 group was significantly lower than that in SCII group(P<0.05).The ra-tio of LC3-II/LC3-I and the expression of GABARAP in SCII group and LXA4 group was significantly higher than those in sham group(P<0.05).The ratio of LC3-II/LC3-I in spinal cord tissue significantly declined compared with that of SCII group(P<0.05).Conclusion The autophagy is activated when SCII occurs,indicating that the autophagy is involved in SCII.After LXA4 is adminis-tered,autophagy is inhibited and SCII is alleviated.