自噬通过抑制凋亡促进体外饥饿状态下脂肪细胞存活

 目的: 观察体外饥饿状态下脂肪细胞的自噬变化,研究自噬在维持体外饥饿状态下脂肪细胞存活中的作用。方法: 将小鼠3T3-L1细胞诱导成为脂肪细胞后,雷帕霉素(rapamycin,RAP)预处理脂肪细胞,在缺糖缺氧(oxygen-glucose deprivation,OGD)模拟的饥饿环境中孵育细胞。应用Western blotting及透射电镜法检测细胞自噬变化,用TUNEL染色及Western blotting检测脂肪细胞凋亡。结果: OGD条件下脂肪细胞的自噬水平明显升高,RAP预处理进一步上调了OGD条件下的细胞自噬。与对照组相比,OGD组细胞cleaved caspase-3的水平及细胞凋亡率明显升高(P<0.01)。RAP预处理降低了OGD 条件下cleaved caspase-3的水平,并明显降低了细胞凋亡率(P<0.05)。结论: 自噬在饥饿状态下脂肪细胞存活中发挥保护性作用,提高自噬水平有助于降低饥饿状态下脂肪细胞的凋亡水平。

Autophagy promotes survival of adipose cells by inhibiting apoptosis under in vitro starvation

AIM: To detect the changes of autophagy in adipose cells under starvation, and to clarify the effects of autophagy on the cell survival and apoptosis under starvation. METHODS: Rapamycin (RAP) was applied to promote autophagy of adipose cells. These cells were then incubated under oxygen-glucose deprivation (OGD) condition. After exposure of the cells to OGD, the changes of autophagy and apoptosis were determined by Western blotting, transmission electron microscopy and TUNEL assay. RESULTS: Compared with the control cells, OGD-challenged cells had much higher level of autophagy. The apoptotic rate in OGD group was much higher than that in control group, which was reflected by increased protein level of activated caspase-3 and percentages of TUNEL positive cells. Preconditioning with RAP effectively improved OGD-induced autophagy, but did not affect the cell survival and apoptosis under normal condition, and obviously decreased the apoptotic rate of the cells under OGD condition. CONCLUSION: Autophagy protects adipose cells against starvation-induced apoptosis. Promotion of autophagy is helpful for attenuating starvation-induced apoptosis of the cells under OGD condition.