棕榈酸抑制胰岛MIN6 β细胞生长的分子机制

Effect of Palmitate on proliferation and apoptosis of INS-1 pancreatic β-cell

目的:观察饱和脂肪酸棕榈酸(Palmitate,PA)对小鼠MIN6β细胞生长的影响,从细胞周期角度来探讨其发生的分子机制。方法:采用5g/LBSA代替血清培养36h使MIN6细胞同步化处于G0期。然后用PA(0.25～1.0mmol/L,45min～24h)干预,采用MTT法检测细胞活力,流式细胞术测定细胞周期,采用Westenblot检测细胞周期相关蛋白CDK4、CyclinD1表达水平的变化。结果:和对照组相比(1)不同浓度PA均显著抑制MIN6细胞增殖(P<0.01);(2)PA亦能明显抑制细胞周期进程,使MIN6细胞周期更多滞留在G0/G1期(P<0.01),G2/M期与S期细胞比例降低(P<0.01);(3)PA能显著的抑制细胞周期相关蛋白CDK-4、Cy-clinD1的表达(P<0.05),并与细胞周期延迟一致。结论:PA抑制MIN6β细胞生长可能是通过降低MIN6β细胞的细胞周期相关蛋白cyclinD1/CDK-4的表达,导致从G1-S期的阻滞,从而减弱细胞增殖。

AIM：To investigate the effect of saturated fatty acid Palmitate（PA）on cell viability of MIN6 β-cell and the possible cell cycle pathways affected by PA.METHODS：MIN6 cells were synchronized at G0 phase by serum deprivation for 36 h,and further MIN6 cells were exposed to different concentrations of PA（0.25-1.0 mmol/L,45 min-24 h）compared with control cell treated with BSA.Cell viability was assessed by MTT colorimetric assay.The cell cycle was measured by FACS analysis,and cell cycle proteins were further detected using Western blot.RESULTS：（1）PA significantly affected the cell viability of MIN6 cells.（2）The G0/G1 cell cycle arrest（n=6,P〈0.05）also induced by PA,whereas MIN6 cells in S and G2/M phase were decreased.（3）For cell cycle proteins,PA treatment caused significant reductions in cyclin D1 and CDK4 levels,which was consistent to the cell cycle delay.CONCLUSION：The findings thus suggest that increased PA directly affects pancreatic β-cell proliferation,possibly by reducing the levels of cyclin D1/CDK4 in the cells,which results in arresting in progression through the G1 phase to the S phase of the cell cycle.