上调A1腺苷受体减轻继发性脑损伤

Up-regulation of A1 adenosine receptor in alleviating secondary brain injury

摘要:

目的： 探讨A1腺苷受体（A1 adenosine receptor，A1AR）在脑出血（intracranial hemorrhage，ICH）诱导的继发性脑损伤（secondary brain injury，SBI）中的作用。方法： 将30只成年雄性SD大鼠随机分为假手术组、脑出血组、激动剂组[A1腺苷受体激动剂N（6）-环己基黄素，R-PIA]和拮抗剂组（A1腺苷受体拮抗剂8-苯基-1，3-二丙基黄嘌呤，8-PT），最终每组6只。以胶原酶注射法建立ICH模型。造模前30 min给予激动剂和拮抗剂，48 h后进行检查。分别予免疫蛋白印迹检测A1AR、活性Caspase-3、白蛋白、B淋巴细胞瘤-2基因（B cell lymphoma 2，Bcl-2）、Bax的表达；脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（TdT-mediated dUTP nick-end labeling，TUNEL）观察神经元凋亡；湿/干比法评估脑水肿程度。结果： 激动剂组A1AR的表达明显上调（P=0.000），拮抗剂组A1AR的表达下调。激动剂组细胞凋亡减少（P=0.003），活性Caspase-3、白蛋白的水平下调（t=4.649，P=0.043；t=24.89，P=0.001）。拮抗剂组细胞凋亡增多，活性Caspase-3、白蛋白水平上调（t=12.49，P=0.006；t=8.501，P=0.013）。激动剂组Bcl-2表达增加（t=14.13，P=0.005）、Bax表达下调，脑水肿程度减轻（P=0.007）。结论： 激活A1AR可增加Bcl-2表达，减轻脑水肿，减少神经细胞凋亡，抑制继发性脑损伤。

Abstract:

Objective: To investigate the role of A1 adenosine receptor (A1AR) in secondary brain injury (SBI) induced by intracranial hemorrhage (ICH). Methods: Thirty adult male SD rats were randomized into sham operation group, ICH group, agonist group [A1 adenosine receptor agonist N (6) -cyclohexylflavin, R-PIA] and antagonist group (A1 adenosine receptor antagonist 8-phenyl-1, 3-dipropylxanthine, 8-PT), with 6 rats in each group. A collagenase-induced ICH model was established. The agonists and antagonists were administered 30 minutes before modeling and examinations were performed 48 hours later. The expressions of A1AR, active Caspase-3, albumin, B cell lymphoma 2 (Bcl-2) and Bax were detected by Western blot. The apoptosis of neurons was observed by TdT-mediated dUTP nick-end labeling (TUNEL). The degree of brain edema was evaluated by wet/dry ratio. Results: The expression of A1AR in agonist group was significantly up-regulated (P=0.000), while that in antagonist group was down-regulated. In agonist group, apoptosis decreased (P=0.003), and the levels of active Caspase-3 and albumin decreased (t=4.649, P=0.043; t=24.89, P=0.001). In the antagonist group, apoptosis increased, and the levels of active Caspase-3 and albumin were up-regulated (t=12.49, P=0.006; t=8.501, P=0.013). In agonist group, Bcl-2 expression increased (t=14.13, P=0.005), Bax expression decreased, and the degree of brain edema decreased (P=0.007). Conclusion: Activation of A1AR can increase the expression of Bcl-2, relieve brain edema, reduce nerve cell apoptosis and inhibit secondary brain injury.