Health Sciences University, Bağcılar Training and Research Hospital, Neurosurgery Clinic, Istanbul, Turkey.
Istanbul University, Institute of Graduate Studies in Sciences, Department of Molecular Biology and Genetics, Istanbul, Turkey.
Brain Res. 2021 Aug 15;1765:147508. doi: 10.1016/j.brainres.2021.147508. Epub 2021 Apr 28.
Cerebral vasospasm (CVS) causes mortality and morbidity in patients after subarachnoid hemorrhage (SAH). The mechanism and adequate treatment of CVS are still elusive. R-568 is a calcimimetic agent known to exert a vasodilating effect. However, there is no report on its vasodilator effect against SAH-induced vasospasm. In the present study, we investigated the therapeutic effect of R-568 on the SAH-induced CVS model in rats. Seventy-two adult male Sprague-Dawley rats were divided into 8 groups: sham surgery; SAH only; SAH + Vehicle, SAH + R-568; SAH + R-568 + Wortmannin (the PI3K inhibitor); SAH + Wortmannin; SAH + R-568 + Calhex-231 (a calcilytic agent); SAH + Calhex-231. SAH was induced by blood (0.3 mL) given by intracisternal injection. R-568 (20 µM) was administered intracisternal immediately prior to experimental SAH. Basilar arteries (BAs) were obtained to evaluate PI3K/Akt/eNOS pathway (immunoblotting) and morphological changes 48 h after SAH. Perimeters of BAs were decreased by 24.1% in the SAH group compared to the control group and the wall thickness was increased by 75.3%. With R-568 treatment, those percentages were 9.6% and 29.6%, respectively, indicating that vasospasm was considerably improved when compared with the SAH group (P < 0.001 in both). While p-PI3K/PI3K and p-Akt/Akt ratio and eNOS protein expression were markedly decreased in the SAH rats, treatment with R-568 resulted in a significant increase in these levels. The beneficial effects of R-568 were partially blocked in the presence of Calhex-231 and completely blocked in the presence of Wortmannin. Herein, we found that treatment with R-568 would attenuate SAH-induced CVS through the PI3K/Akt/eNOS pathway and demonstrate therapeutic promise in CVS treatment following SAH.
蛛网膜下腔出血 (SAH) 后，脑血管痉挛 (CVS) 可导致患者死亡和发病。CVS 的发病机制和有效治疗方法仍不明确。R-568 是一种已知具有血管扩张作用的钙敏感受体激动剂。然而，目前尚无关于其对蛛网膜下腔出血诱导的血管痉挛的血管扩张作用的报道。在本研究中，我们研究了 R-568 对大鼠蛛网膜下腔出血诱导的 CVS 模型的治疗效果。72 只成年雄性 Sprague-Dawley 大鼠分为 8 组：假手术组；SAH 组；SAH+Vehicle 组、SAH+R-568 组、SAH+R-568+Wortmannin（PI3K 抑制剂）组、SAH+Wortmannin 组、SAH+R-568+Calhex-231（钙敏感受体拮抗剂）组、SAH+Calhex-231 组。通过脑室内注射给予 0.3ml 血液诱导 SAH。R-568（20μM）在实验性 SAH 前立即脑室内给药。SAH 后 48 小时获取基底动脉（BA），评估 PI3K/Akt/eNOS 通路（免疫印迹）和形态学变化。与对照组相比，SAH 组 BA 周长减少了 24.1%，壁厚度增加了 75.3%。用 R-568 治疗后，分别为 9.6%和 29.6%，与 SAH 组相比，血管痉挛明显改善（均 P<0.001）。在 SAH 大鼠中，p-PI3K/PI3K 和 p-Akt/Akt 比值以及 eNOS 蛋白表达明显降低，而用 R-568 治疗后这些水平显著升高。Calhex-231 的存在部分阻断了 R-568 的有益作用，Wortmannin 的存在完全阻断了其作用。在此，我们发现 R-568 治疗可通过 PI3K/Akt/eNOS 通路减轻 SAH 诱导的 CVS，并证明其在 SAH 后 CVS 治疗中有治疗潜力。
