细胞周期蛋白质依赖激酶抑制因子在血管平滑肌细胞增殖与增生中的作用

目的探讨细胞周期蛋白依赖激酶抑制因子p27、p21和p57在血管平滑肌细胞(VSMC)增殖与增生过程中的调控作用.方法分离SD大鼠主动脉中层平滑肌,贴壁法培养平滑肌细胞,无血清培养基培养静止后,分别加入AngⅡ10-6mol/L,血小板源生长因子(PDGF)20ng/ml和10%FBS,在刺激后6、12、24h分别收集细胞,以无血清培养基培养的VSMC作静止对照,以10%FBS刺激的VSMC作增殖对照.用Westernblot分别检测p27、p57和p21蛋白表达量.结果在AngⅡ刺激的VSMC中,p21,p57和p27蛋白表达水平与静止的VSMC中相近,无明显变化(P>0.05);而在PDGF-BB刺激的VSMC中,p21蛋白表达量随刺激时间延长而逐渐增加,在刺激后12h开始增加,24h达高峰(A值为1.578±0.133,对照组A值为1.000±0.011,P<0.01);p57蛋白表达量在刺激24h增加(A值为1.641±0.342,对照组A值为1.000±0.016,P<0.01);p27蛋白表达量随刺激时间延长而逐渐下降,在24h下降最明显(A值为0.401±0.137,对照组A值为0.985±0.023,P<0.01).结论p21和p57的主要作用在于防止VSMC细胞过度增殖.p27蛋白表达量的变化是决定VSMC增殖的关键,并参与VSMC增生的诱导和维持.

The role of cyclin-dependent kinase inhibitors in hyperplasia and hypertrophy of vascular smooth muscle cells

Objective To investigate the role p27, p21, and p57, different cyclin dependent kinase inhibitors (CKIs), play in the hyperplasia and hypertrophy of vascular smooth muscle cells (VSMCs) stimulated with platelet derived growth factor (PDGF BB) and angiotensin II (Ang II). Methods VSMCs from rat aorta were cultured. PDGF BB and Ang II were added into the serum-free media at the concentrations of 10 6 M and 20 ng/ml respectively. VSMCs were harvested after 6h, 12h, and 24 h or stimulation. The protein levels of p27, p21 and p57 in VSMCs were examined with Western blot analysis. Results The protein levels of p27, p21, and p57 in the Ang II stimulated VSMCs were similar to those in the quiescent cells ( P >0.05). The protein levels of p21 and p57 in the PDGF BB stimulated VSMCs increased along with the time course of stimulation, the former being at its peak value at the 24th hour, and were significantly higher than those in Ang II stimulated VSMCs. However, the p57 protein level was high in the quiescent cells. A remarkable decrease of the p57 protein level was found in the PDGF BB stimulated VSMCs ( P <0.01). Conclusion p27, p21, and p57 proteins play important roles in regulating hyperplasia and hypertrophy of VSMC. P21 and p57 prevent the overplasia of VSMCs. P27 is the most important regulator of hyperplasia and hypertrophy of VSMC stimulated by PDGF and Ang II.