Department of Anesthesiology, The Fourth Affiliated Hospital, Harbin Medical University, 150001 Harbin, China.
Brain Res. 2010 Oct 14;1356:11-23. doi: 10.1016/j.brainres.2010.08.012. Epub 2010 Aug 11.
Transient cerebral ischemia may result in neuronal apoptosis. During this process, several apoptosis-regulatory genes are induced in apoptotic cells. Among these genes, cysteinyl aspartate-specific protease-3 (caspase-3) and B-cell leukemia-2 (Bcl-2) are the most effective apoptotic regulators because they play a decisive role in the occurrence of apoptosis. Research has shown that propofol, which is an intravenous anesthetic agent, exhibits neuroprotective effects against cerebral ischemia-reperfusion injury, although the neuroprotective mechanism is still unclear. In this study, we examined the effects of propofol in rats after forebrain ischemia-reperfusion. We assessed the expression of hippocampal caspase-3, which acts as an apoptotic activator, and Bcl-2, which acts as an apoptotic suppressor. Forebrain ischemia was induced in hypotensive rats by clamping the bilateral common carotid arteries for 10 min. Propofol was administered via a lateral cerebral ventricle injection using a microsyringe after the induction of ischemia. Neuronal damage was determined by histological examination of brain sections at the level of the dorsal hippocampus. Caspase-3 and Bcl-2 expression in the hippocampus were detected using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. We also used an immunohistochemical method after ischemia-reperfusion. In the hippocampus, caspase-3 and Bcl-2 mRNA were dramatically increased at 24h after forebrain ischemia. Following 6-24h of reperfusion, forebrain ischemia for 10 min induced a gradual increase in the expression of caspase-3 and Bcl-2 protein in the rat hippocampus, which peaked at 24h. In the propofol (1.0mg/kg) intervention group, the hippocampal expression of caspase-3 mRNA decreased significantly in rats 24h after ischemia; Bcl-2 mRNA was increased at the same time point. During the 24-h reperfusion period and after treatment with propofol, the level of caspase-3 protein expression was low, while the level of Bcl-2 was high. Thus, our results suggest that the neuroprotective effects of propofol against neuronal apoptosis may be mediated by the inhibition of caspase-3 expression and an increase in Bcl-2 expression.
短暂性脑缺血可能导致神经元细胞凋亡。在这个过程中,凋亡细胞中会诱导几种凋亡调控基因。在这些基因中,半胱氨酸天冬氨酸特异性蛋白酶-3(caspase-3)和 B 细胞淋巴瘤-2(Bcl-2)是最有效的凋亡调控因子,因为它们在凋亡的发生中起着决定性的作用。研究表明,丙泊酚作为一种静脉麻醉剂,对脑缺血再灌注损伤具有神经保护作用,尽管其神经保护机制尚不清楚。在这项研究中,我们观察了丙泊酚对大脑前缺血再灌注大鼠的影响。我们评估了海马 caspase-3 的表达,caspase-3 作为凋亡激活剂,Bcl-2 作为凋亡抑制物。通过夹闭双侧颈总动脉 10 分钟,在低血压大鼠中诱导大脑前缺血。在诱导缺血后,使用微量注射器通过侧脑室注射给予丙泊酚。通过对背侧海马脑切片的组织学检查来确定神经元损伤。使用半定量逆转录-聚合酶链反应(RT-PCR)和 Western blot 分析检测海马中的 caspase-3 和 Bcl-2 表达。我们还在缺血再灌注后使用免疫组织化学方法。在海马中,大脑前缺血后 24 小时 caspase-3 和 Bcl-2mRNA 显著增加。在再灌注 6-24 小时后,大脑前缺血 10 分钟导致大鼠海马中 caspase-3 和 Bcl-2 蛋白表达逐渐增加,24 小时达到高峰。在丙泊酚(1.0mg/kg)干预组中,缺血后 24 小时大鼠海马 caspase-3mRNA 的表达明显降低;同时 Bcl-2mRNA 增加。在 24 小时再灌注期间和丙泊酚治疗后,caspase-3 蛋白表达水平较低,而 Bcl-2 水平较高。因此,我们的结果表明,丙泊酚对神经元凋亡的神经保护作用可能是通过抑制 caspase-3 表达和增加 Bcl-2 表达来介导的。