摘要
目的:研究西洋参茎叶总皂苷(PQS)减轻毒胡萝卜素(TG)诱导的心肌细胞凋亡的分子机制。方法:原代培养的心肌细胞分为:control组、TG组、PQS(40 mg/L、80 mg/L及160 mg/L)+TG组、牛磺酸(40mmol/L)+TG组、蛋白激酶R样内质网激酶(PERK)敲低+TG组及随机双链RNA转染对照(mock)+TG组。通过向培养液中加入1μmol/L TG作用24 h诱导离体培养的乳大鼠心肌细胞凋亡。以RNAi方法敲低心肌细胞PERK基因。CCK-8法和流式细胞术检测细胞活性及凋亡率,Western blotting方法检测内质网应激(ERS)标志分子葡萄糖调节蛋白78(GRP 78)、钙网蛋白(CRT)、PERK、p-PERK、真核起始因子2α(eIF2α)、p-eIF2α、活化转录因子4(ATF4)、C/EBP同源蛋白(CHOP)及凋亡相关蛋白Bcl-2、Bax的表达。结果:与对照组比较,TG孵育明显诱导细胞凋亡,降低细胞活力,上调PERK和eIF2α磷酸化以及GRP78、CRT、ATF4、CHOP及促凋亡蛋白Bax表达,降低抗凋亡蛋白Bcl-2表达(P<0.05);与TG组比较,PQS 160 mg/L及敲低PERK均可显著降低细胞凋亡率,升高细胞活力(P<0.05);3种不同浓度的PQS可呈剂量依赖性降低Bax蛋白表达,升高Bcl-2蛋白表达(P<0.05),敲低PERK基因及PQS(160 mg/L)预处理均可降低ERS分子GRP78、CRT、ATF4及CHOP表达,降低PERK及eIF2α的磷酸化水平(P<0.05)。结论:PQS 160 mg/L减轻ERS诱导剂TG诱导的心肌细胞凋亡,PQS预处理可以模拟PERK敲低减轻TG致心肌细胞凋亡的效应,提示PERK-eIF2α-ATF4-CHOP途径参与PQS减轻ERS相关凋亡的作用。
AIM: To study the effect of Panax quinquefolium saponin( PQS) on cardiomyocyte apoptosis induced by thapsigargin( TG). METHODS: Primary cultured cardiomyocytes from neonatal SD rats were divided into control group,TG group,PQS( 40 mg /L,80 mg /L and 160 mg /L) + TG group,si-PERK + TG group,and mock + TG group. The cells were treated with 1 μmol /L TG for 24 h to induce apoptosis. The PERK gene in the cardiomyocytes was knocked down by RNAi. The cell viability was detected by CCK-8 assay. Apoptosis was analyzed by flow cytometry. Western blotting was used to determine the expression of ERS molecules GRP78,CRT,ATF4 and CHOP,anti-apoptosis protein Bcl-2 and pro-apoptosis protein Bax. RESULTS: Compared with control group,TG significantly and the apoptosis,reduced the cell viability( P 〈0.05),increased the phosphorylation of PERK and eIF2α,increased the expression of GRP78,CRT,ATF4,CHOP and pro-apoptosis protein Bax,and decreased the expression of anti-apoptosis protein Bcl-2( P〈 0.05). Compared with TG group,PQS treatment( 160 mg/L) significantly reduced the apoptosis and increased the cell viability( P 〈0.05). All the 3 different concentrations of PQS significantly increased the expression of anti-apoptosis protein Bcl-2 and reduced the expression of pro-apoptosis protein Bax( P〈 0.05) in a dose-dependent manner. PQS pretreatment and knockdown of PERK both reduced the protein levels of GRP78,CRT,PERK,p-PERK,eIF2α,p-eIF2α,ATF4,CHOP and pro-apoptosis protein Bax,and increased the expression of anti-apoptosis protein Bcl-2( P 〈0.05).CONCLUSION: PQS at concentration of 160 mg /L attenuated cardiomyocyte apoptosis induced by TG. PQS had the similar effect as PERK knockdown on cardiomyocyte apoptosis. The mechanism may be associated with inhibiting PERK-eIF2α-ATF4-CHOP pathway of ERS-related apoptosis.
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2014年第10期1735-1741,共7页
Chinese Journal of Pathophysiology
基金
国家自然科学基金资助项目(No.81170140
No.81030063)
关键词
西洋参茎叶总皂苷
毒胡萝卜素
心肌细胞凋亡
内质网应激
Panax quinquefolium saponin
Thapsigargin
Cardiomyocyte apoptosis
Endoplasmic reticulum stress