Effect of rapamycin on cell prolification of glomerular mesangial cells by high glucose

Objective To study the effect of rapamycin on cell proliferation of glomerular mesangial cells (GMC) induced by high glucose. Methods Glomerular mesangial cells were cultured with high glucose and different concentration of rapamycin. Cell proliferation rate was measured by MTT. The mRNA and protein levels of cyclin D1, cyclin E and p27~(KIP1) were examined by reverse transcription PCR (RT-PCR) and Western blot analysis respectively. The changes in cell cycles were detected by flow cytometery. Results High glucose could induce GMC prolification, and rapamycin could significantly and dose-dependently inhibit the effect (P 0. 05). The mRNA and protein expressions of cyclin D1 and cyclin E were more down-regulated in rapamycin groups than in high glucose group. And the p27~(KIP1) protein expression was more up-regulated in rapamycin groups than in high glucose group. In high glucose versus control groups, cell cycle distribution of G_0/G_1 stage were much lower (61.8%±0. 002% versus 83. 8% ±-0. 017%) and S stage much higher (26.2% ±0. 022% versus 0. 2 % ± 0. 004 %) ( P 0.05 ). Under cultured cells with 1, 2, 5ng/ml of rapamycin, the cell cycle distribution of G_0/G_1 stage became much higher (61.8% ± 0. 017% versus 63.3% ± 0. 034%, 69. 5% ± 0. 013%, 73. 3% ± 0.001% respectively, and S stage much lower (26.2%± 0. 022% versus 19.0% ± 0. 027%, 12. 0%±0. 016%, 9. 6%±0. 009%) (P0. 05). Conclusions Rapamycin could dose-dependently inhibit prolification of glomerular mesangial cells induced by high glucose. The possible mechanism is that rapamycin participates the G_1/S arrest by down-regulating the mRNA and protein expressions of cyclin D1 and cyclin E, and upregulating p27~(KIP1) protein level.