右美托咪定对大鼠海马神经元缺氧复氧损伤时线粒体途径凋亡的影响

Effect,of dexmedetomidine on mitochondrion-dependent apoptosis during hypoxia-reoxygenation injury to hippocampal neurons of rats

目的评价右美托咪定对大鼠海马神经元缺氧复氧损伤时线粒体途径凋亡的影响。方法原代培养的海马神经元,采用随机数字表法分为4组(n=40):对照组(C组)、赋形剂组(V组)、缺氧复氧组(H/R组)和右美托咪定组(D组)。采用氧糖剥夺法建立海马神经元缺氧复氧模型。D组缺氧6h时加入右美托咪定1μmol/L。于复氧20h时,采用MTT法检测神经元活力,透射电镜观察线粒体超微结构,Western blot法检测细胞色素c(Cyt c)、caspase.3、Fisl和Drpl表达,流式细胞术检测神经元凋亡率。结果与c组比较,V组神经元活力差异无统计学意义(P>0.05),H/R组和D组神经元活力降低,凋亡率升高,Cyt c、caspase-3、Fis1和Drp1表达上调(P<0.05),线粒体超微结构破坏加重。与H/R组比较,D组神经元活力升高,凋亡率降低,Cyt c、caspase-3、Fis1和Drp1表达下调(P<0.05),线粒体超微结构破坏减轻。结论右美托咪定减轻大鼠海马神经元缺氧复氧损伤的机制与抑制线粒体途径凋亡有关。

Objective To evaluate effect of dexmedetomidine on mitoehondrion-dependent apoptosis during hypoxia-reoxygenation (H/R)injury to hippocampal neurons of rats.Methods The primarily cultured hippocampal neurons of Sprague-Dawley rats were divided into 4groups (n=40each)using a random number.table method:control group (C group),vehicle group (V group),H/R group and dexmedetomidine group (D group).Hippocampal neurons were subjected to oxygen-glucose deprivation followed by restoration of oxygen stipply to establish the model of H/R injury.Dexmedetomidine 1μmol/L was added at 6h of reoxygenation in D group.The viability of neurons was measured by methyl thiazolyl tetrazolium assay at 20h of reoxygenation.The ultrastructure of mitochondria was observed by transmission electron microscopy.The expression of cytochrome c (Cyt c),caspase-3,Fisl and Drpl was detected by Western blot.The neuronal apoptosis was detected by flow cytometry,and apoptosis rate was calculated.Results Compared with C group,no significant change was found in the viability of neurons in group V (P>0.05), and the viability of neurons was significantly decreased,the apoptosis rate was increased,the expression of Cyt c,caspase-3,Fisl and Drpl was up-regulated (P<0.05),and the damage to mitochondrial ultrastructure was accentuated in H/R and D groups.Compared with H/R group,the viability of neurons was significantly increased,the apoptosis rate was decreased,the expression of Cyt c,caspase-3,Fisl and Drpl was down-regulated (P<0.05),and the damage to mitochondrial ultrastructure was significantly attenuated in D group.Conclusion The mechanism by which dexmedetomidine reduces the H/R injury tohippocampal neurons is related to inhibiting mitochondrion-dependent apoptosis in rats.