星形胶质细胞与JAK—STAT通路在兔脊髓缺血再灌注损伤后变化规律的研究

The temporal profile of astrocytes and Jak-STAT signal pathway after spinal ischemia and reperfusion injury in rab- bits

目的观察兔脊髓缺血再灌注后星形胶质细胞（AS）、胶质细胞源性神经营养因子（GDNF）、脑源性神经营养因子（BDNF）以及Janus激酶／信号转导和转录激活子（Jak—STAT）的表达规律。方法采用胸主动脉阻断法建立兔脊髓缺血（22min）／再灌注损伤模型。健康成年（36周）雄性新西兰白兔54只，随机分为0h、1h、2h、3h、8h、24h、48h、72h组和假手术组（每组6只）。缺血再灌注组分别于缺血再灌注后相应时间点检测缺血段脊髓组织中正常神经元、星形胶质细胞特征性标记物（GFAP）、GDNF、BDNF及p-STAT3的表达水平。结果正常神经元数量随着再灌注时间延长而减少；免疫组化染色结果显示，再灌注后3hGFAP表达水平开始增多，48h达到高峰；GDNF在再灌注后3h和72h各达到1次高峰；再灌注后24hBDNF表达水平最高；p-STAT3表达水平分别在再灌注后1h和48h到达高峰。结论脊髓缺血再灌注损伤可以诱发AS激活，神经营养因子GDNF、BDNF水平升高，Jak—STAT信号通路激活并呈现不同的表达规律。

Objective To observe the evolution of astrocytes, GDNF, BDNF and Jak-STAT signal pathway ＇after spinal cord ischemia-reperfusion injury in rabbits. Methods Spinal cord ischemia was induced by means of balloon occlusion of the infrarenal aorta for 22 minutes in 54 male New Zealand white rabbits. We assigned rabbits to 9 groups （ n = 6 ）, one sham group, eight operation groups. The operation process in the sham group was the same as the operation group except the ischemia reperfusion of the spinal cord. At 0 h, 1 h, 2 h, 3 h, 8 h, 24 h, 48 h and 72 h ＇after reperfusion, animals were sarcrificed and the spinal cord was removed for histologie, immunohistochemieal study and western blotting. Results Normal neurons were decreased with the extension of reperfusion time. Levels of GFAP increased at 3 h and reached a peak at 48 h after reperiusion. GDNF was increased reaching two peaks after injury, the first peak was at 3 h, the second was at 72 h. BDNF level was in- creased and peaked at 24 h after reperfusion. The expression of p-STAT3 showed a biphasic pattern which peaked at 1 h and 48 h. GFAP, GDNF, BDNF were rare and the level of p-STAT3 could be neglected in sham group. Conclusion Spinal cord is- chemia-reperfusion injury could induce the activation of astrocytes, the expression of GDNF, BDNF and the activation of Jak- STAT signal pathway. They showed different expression rules in this study.