Neuroprotection of dexmedetomidine against propofol-induced neuroapoptosis partly mediated by PI3K/Akt pathway in hippocampal neurons of fetal rat

Abstract

The aim was to investigate how the PI3K/Akt pathway is involved in the protection of dexmedetomidine against propofol. The hippocampal neurons from fetal rats were separated and cultured in a neurobasal medium. Cell viability was assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Then neurons were pretreated with different concentrations of dexmedetomidine before 100 μmol/L propofol was added. Akt, phospho-Akt (p-Akt), Bad, phospho-Bad (p-Bad), and Bcl-xL were detected by Western blot. Also, neurons were pretreated with dexmedetomidine alone or given the inhibitor LY294002 before dexmedetomidine pretreatment, and then propofol was added for 3 h. The results demonstrated that propofol decreased the cell viability and the expression of p-Akt and p-Bad proteins, increased the level of Bad, and reduced the ratio of Bcl-xL/Bad. Dexmedetomidine pretreatment could reverse these effects. The enhancement of p-Akt and p-Bad induced by dexmedetomidine was prevented by LY294002. These results showed that dexmedetomidine potently protected the developing neuron and this protection may be partly mediated by the PI3K/Akt pathway.

中文概要

目的

研究PI3K/Akt 信号通路是否参与了右美托咪定 对异丙酚诱导的胎鼠海马神经元凋亡的保护作 用,并初步探讨可能的作用机制。

创新点

首次利用胎鼠海马神经元研究发现右美托咪定对 异丙酚诱导的神经元凋亡作用部分是由 PI3K/Akt 信号通路介导的。

方法

首先分离胎鼠海马神经元并鉴定。使用MTT 法 检测异丙酚对神经元活性的影响。然后将神经元 分为不同的组,分别用0.1、1、10 和100 μmol/L 右美托咪定预处理细胞,然后加入100 μmol/L 的异丙酚继续培养,同时设异丙酚组和正常对照 组。使用蛋白质印迹(Western blot)方法检测 Akt、p-Akt、Bad、p-Bad 和Bcl-xL 的表达变化。 在100 μmol/L 右美托咪定预处理前加入 LY294002,进一步研究PI3K/Akt 途径是否参与 了右美托咪定对异丙酚诱导的胎鼠海马神经元 凋亡的保护作用。

结论

实验结果显示,异丙酚明显降低了神经元的细胞 活性及p-Akt 和p-Bad 的表达水平,增加了Bad 的表达,从而Bcl-xL/Bad 的比率升高。100 μmol/L 右美托咪定预处理可以逆转这种效果。 LY294002 可以抑制右美托咪定的保护作用,说 明右美托咪定对异丙酚诱导的胎鼠海马神经元 凋亡的保护作用部分是由PI3K/Akt 信号通路介 导的。