Experimental Study of Effect of Rapamycin on Proliferation of Rat Aortic Smooth Muscle Cells

To evaluate the proliferative effect of rapamycin on the cultured rat thoracic aortic smooth muscle cells(SMC) in vitro.【Methods】 The rat thoracic aortic SMC were harvested and cultured for six to ten passages.Cultured SMC were synchronized,then restimulated to enter the cell cycle,and treated with incremental concentrations of rapamycin or without rapamycin as contrast.Forty-eight hours after managed,the proliferative assay was performed with MTT method and RT-PCR was performed to assay the level of proliferating cell nuclear antigen(PCNA) mRNA.【Result】(1) Rapamycin progressively inhibits rat aortic SMC proliferation in a concentration-dependent fashion.The absorption(A) value of each group was statistically significant for different concentrations(F=28.85,P 0.001) and the results were: control,0.902±0.106;0.1 ng/mL,0.873±0.079;1 ng/mL,0.797±0.046;10 ng/mL,0.692±0.061;100 ng/mL,0.624±0.075.Compared to control group or among the different concentration,the difference of A value was statistically significant when the concentration of rapamycin was greater than 1 ng/mL.The difference was not statistically significant when the concentration was 0.1 ng/mL.(2) RT-PCR suggested rapamycin significantly decreased rat aortic SMC PCNA-mRNA transcription in a concentration-dependent fashion.The results of statistical analysis were similar with MTT assay(F=195.491,P 0.001).The optic density values of each group were: control,219.35±7.20;0.1 ng/mL,212.39±6.56;1 ng/mL,113.15±10.09;10 ng/mL,97.17±12.25;100 ng/mL,84.38±8.66.【Conclusion】 Rapamycin inhibits rat aortic SMC proliferation in a concentration-dependent fashion.It is suggested the action concentration was 1 ng/mL.Rapamycin maybe one of the best drugs in the treatment of the in-stent restenosis after vascular interventional operation.