Akt激活剂SC79抑制地塞米松诱导成骨细胞凋亡和程序性坏死的作用机制

Mechanism by which SC79,an Akt activator,inhibits dexamethasone-induced apoptosis and programmed necrosis of osteoblasts

背景:有研究发现SC79(一种Akt激活剂)具有一定的细胞保护作用,其不仅能够抑制兴奋性中毒,还能够减轻由于脑卒中等原因引起的神经元细胞死亡。目的:探究SC79抑制地塞米松诱导成骨细胞凋亡和程序性坏死的作用机制。方法:取对数生长期的人成骨细胞株OB-6,分4组处理:对照组常规培养,地塞米松组加入2μmol/L地塞米松处理24 h;SC79组加入20μmol/L SC79处理24 h;SC79+地塞米松组首先加入20μmol/L SC79处理2 h,再加入2μmol/L地塞米松处理24 h。检测细胞活性、乳酸脱氢酶释放、凋亡率、凋亡相关因子Caspase-3、Bax、Bcl-2的活性,以及氧化应激相关因子亲环蛋白D、细胞色素C的蛋白表达。结果与结论:①与对照组比较,地塞米松组细胞活性降低(P<0.05);与地塞米松组比较,SC79+地塞米松组细胞活性升高(P<0.05);②与对照组比较,地塞米松组细胞乳酸脱氢酶释放、线粒体膜电位升高(P<0.05);与地塞米松组比较,SC79+地塞米松组细胞乳酸脱氢酶释放、线粒体膜电位强度降低(P<0.05);③与对照组比较,地塞米松组Caspase-3、Bax的活性及细胞凋亡率升高(P<0.05),Bcl-2蛋白表达降低(P<0.05);与地塞米松组比较,SC79+地塞米松组Caspase-3、Bax的活性及细胞凋亡率降低(P<0.05),Bcl-2蛋白表达升高(P<0.05);④与对照组比较,地塞米松组亲环蛋白D、细胞色素C蛋白表达升高(P<0.05);与地塞米松组比较,SC79+地塞米松组亲环蛋白D、细胞色素C蛋白表达降低(P<0.05);⑤结果表明,SC79可以通过增强细胞活性及抑制细胞凋亡、线粒体膜电位强度及氧化应激水平抑制地塞米松诱导的成骨细胞凋亡和程序性坏死。

BACKGROUND:SC79 is an Akt activator that has a certain cytoprotective effect.It cannot only inhibit excitotoxicity,but also reduce neuronal cell death caused by stroke.OBJECTIVE:To investigate the mechanism of SC79 inhibiting dexamethasone-induced apoptosis and programmed necrosis of osteoblasts.METHODS:Human osteoblasts,OB-6 cells,in logarithmic growth phase were divided into four groups:normal culture group,dexamethasone group treated with 2μmol/L dexamethasone for 24 hours,SC79 group treated with 20μmol/L SC79 for 24 hours,and SC79+dexamethasone group treated with 20μmol/L SC79 for 2 hours and then 2μmol/L dexamethasone for 24 hours.Cell activity,lactate dehydrogenase release,and apoptosis rate were detected.Activities of apoptosis-related factors Caspase-3,Bax,and Bcl-2,and the protein expression of oxidative stress-related factors cyclophilin D and cytochrome C were measured.RESULTS AND CONCLUSION:Compared with the normal control group,the dexamethasone group significantly decreased cell activity(P<0.05),increased lactate dehydrogenase release and mitochondrial membrane potential intensity(P<0.05),elevated Caspase-3 and Bax activities and apoptosis rate(P<0.05),decreased the expression of Bcl-2 protein(P<0.05),and upregulated the expression levels of cyclophilin D and cytochrome C proteins(P<0.05).Compared with the dexamethasone group,the SC79+dexamethasone group significantly increased cell activity(P<0.05),reduced lactate dehydrogenase release and mitochondrial membrane potential intensity(P<0.05),decreased Caspase-3 and Bax activities and apoptosis rate(P<0.05),elevated the expression of Bcl-2 protein(P<0.05),and downregulated the expression levels of cyclophilin D and cytochrome C proteins(P<0.05).To conclude,SC79 can inhibit dexamethasone-induced apoptosis and programmed necrosis of osteoblasts by enhancing cell activity and inhibiting apoptosis,mitochondrial membrane potential and oxidative stress.