葡萄糖浓度对乳鼠心肌细胞自噬的影响

目的观察葡萄糖浓度对乳鼠心肌细胞自噬的影响。方法建立体外培养乳鼠心肌细胞模型，随机分成对照组（5．5mmol／L），高糖组（25mmol／L），对照＋雷帕霉素组（100nmol／L），高糖＋雷帕霉素组（100nmol／L）。分别测定各组心肌细胞面积；用RT-PCR检测心肌肥大标记基因[心房利钠肽（ANP）、β-肌球蛋白重链（13-MHC）]表达情况；运用Western印迹检测自噬标记性蛋白微管相关蛋白3（LC-3）的表达。结果（1）高糖组心肌细胞肥大相关指标较对照组升高，高糖组LC-3的表达较对照组减低，差异均有统计学意义（P〈0．05）。（2）高糖＋雷帕霉素组心肌细胞肥大相关指标较对照＋雷帕霉素组升高，高糖＋雷帕霉素组LC-3较对照＋雷帕霉素组减低，但差异均无统计学意义。（3）高糖＋雷帕霉素组心肌细胞肥大相关指标较高糖组减低，高糖＋雷帕霉素组LC-3表达较高糖组升高，差异均有统计学意义。结论（1）培养基中葡萄糖浓度升高可导致心肌细胞肥大，同时合并有心肌细胞自噬水平的下降。（2）在高糖培养基中加入雷帕霉素可升高心肌细胞的自噬水平，同时抑制高糖导致心肌细胞肥大效果。（3）培养基中葡萄糖浓度升高导致心肌细胞肥大的效果可能与心肌细胞自噬水平的改变相关。（4）结合本实验的研究结果，自噬在糖尿病性心肌病方面可能起一定作用。

Effect of glucose concentrations on autophagy in neonatal rat cardiomyocyte

Objective To investigate the effects of glucose concentrations on autophagy in neonatal rat eardiomyocyte. Methods Neonatal ventricular myocytes were culfured for 24 h as a model, divided into four groups as follows： control group （5.5retool/L）, high glucose （25retool/L）, control group （5.5mmol/L） add rapamycin （100nm/L） , high glucose（25mmol/L）add rapamycin （100nm/L）. Cells were visualized with an inverted microscopy. Cardiomyocyte cells surface area was determined using Mo- cha Software. RT-PCR was performed to identified mRNA expression of hypertrophy-related ANP （atrial natriuretic peptid） and β-MHC （β-myosin heavy chain） gene. Western blotting was performed to identify protein expression of autophagy-related marker microtubule-associated protein 3 （ LC-3 ）. Results （ 1 ） Cardiac hypertrophy index in high glucose group was increased significantly than the control group （P 〈 O. 05 ） ; LC-3 in high glucose was reduced significantly than the control group （ P 〈 0.05 ）. （2） Indica- tors of myocardial hypertrophy in high glucose ＋ rapamycin group was increased than in the control ＋ rapa- mycin group, LC-3 in high glucose ＋ rapamycin group was reduced than the control ＋ rapamycin group, But all the differences were not statistically significant. （3） Indicators of cardiac hypertrophy in high glu-cose ＋ rapamycin group was reduced than the high glucose group （ P 〈 0.05 ）, LC-3 in high glucose ＋ rapamycin group was increased than high glucose group （P 〈 0.05 ）. The difference were sfatictically sig- nificant. Conclusions （ 1 ） High glucose levels can lead to cardiac hypertrophy. The level of autophagy in myocardial ceils is decreased. （2） In high glucose medium, rapamycin can increase the level of auto- phagy in myocardial cells, and can inhibit of myocardial hypertrophy caused by high glucose effect. （3） High glucose levels lead to myocardial hypertrophy and these effects may be associated with the level of autophagy. （4） With the findings of this study, autophagy may play a role in diabetic cardiomyopathy.