中文摘要：

背景：既往研究集中于如何促进大鼠脊髓损伤后的神经再生，但对于如何抑制脊髓损伤后星形胶质细胞过度增殖反应的因素、从而改善神经再生的环境研究尚少。 目的：观察 Akt/mTOR/p70S6K 蛋白激酶信号转导通路对大鼠脊髓损伤后反应性星形胶质化形成的影响，从而为改善脊髓损伤后神经再生环境、修复脊髓损伤提供分子学机制依据。 方法：建立SD大鼠轻型脊髓损伤模型，分为4组：实验组造模后行ATP治疗7 d；对照组造模后行等量生理盐水治疗7 d；干预组造模后行等量的ATP联合雷帕霉素治疗7 d；假手术组椎板切除后行等量生理盐水治疗7 d。分别于造模后1，3，7，14 d采用免疫组化、Western blot法检测Akt、p-Akt、mTOR、p-mTOR、p70S6K、p-p70S6K、胶质纤维酸性蛋白表达变化，并采用 BBB 运动功能评分评价大鼠脊髓损伤后经不同方法治疗后运动功能的恢复情况。 结果与结论：假手术组大鼠脊髓中 Akt/mTOR/p70S6K 信号通路分子呈低水平表达，在脊髓损伤后其表达增加。外源性 ATP 可显著增强大鼠受损脊髓中 Akt/mTOR/p70S6K 信号分子的表达，而雷帕霉素可明显抑制ATP诱导的表达上调。激活的Akt/mTOR/p70S6K信号通路可显著减弱受损脊髓组织中胶质纤维酸性蛋白的表达、抑制脊髓损伤后过度的星形胶质细胞增生反应，促进脊髓损伤后BBB运动功能评分增加，而雷帕霉素阻碍了由ATP诱导的上述效应。结果证实，ATP通过诱导Akt/mTOR/p70S6K信号通路激活抑制大鼠脊髓损伤后星形胶质瘢痕的形成，具有改善脊髓损伤后神经再生环境、促进脊髓损伤修复和改善神经功能的潜能，此信号通路是治疗脊髓损伤的重要干预环节。

英文摘要：

BACKGROUND：Most investigations have focused on nerve regeneration after spinal cord injury, but for how to inhibit excessive proliferation response of astrocytes after spinal cord injury and improve nerve regenerative environment is rarely reported. OBJECTIVE：To examine the effects of the protein kinase B/mammalian target of rapamycin/p70 ribosomal S6 protein kinase （Akt/mTOR/p70S6K） signal transduction pathway on excessive astrocytic responses after spinal cord injury in adult rats, and to provide the molecular mechanism evidence for improving nerve regenerative environment fol owing spinal cord injury and repairing spinal cord injury. METHODS：The minimal spinal cord injury model was produced in Spraque-Dawley rats. The rat models were divided into four groups：experiment group （receiving 7-day ATP treatment after modeling）, control group （receiving 7-day saline treatment after modeling）, interference group （receiving 7-day ATP and rapamycin treatment after modeling）, and sham-operated group （receiving 7-day saline treatment after laminectomy）. Using immunohistochemical staining and western blot analyses, we detected the changes of Akt, p-Akt, mTOR, p-mTOR, p70S6K, p-p70S6K, and glial fibril ary acidic protein expressions in spinal cord tissues after surgery. BBB locomotor rating scale was applied to evaluate the animal’s locomotor performance after different treatments were administered fol owing spinal cord injury. RESULTS AND CONCLUSION：The sham-operated group animals exhibited a low expression of the Akt/mTOR/p70S6K signaling pathway at the protein level, and the expressions increased fol owing spinal cord injury. Prominently elevated levels of its components were observed in the ATP-treated group, whereas rapamycin suppressed the upregulations of the Akt/mTOR/p70S6K signaling molecules induced by ATP. Activated Akt/mTOR/p70S6K signaling pathway significantly attenuated expressions of glial fibril ary acidic protein in the injured spinal cord, limited excessive astrocyt