Effects of glyceryl trioleate on the proliferation of rat aortic smooth muscle cells

Abstract:

Objective：To investigate the effects of glyceryl trioleate on the proliferation of rat aortic smooth muscle cells（RASMC）. Methods：Cell culture was used in this experiment. Oil red staining was used to observe changes in cell morphology. The proliferation effect of glyceryl trioleate on RASMC was tested by MTT and flow cytometry. Results：Oil red staining results showed that RASMC lost its long fusiform appearance and somata got bigger. The higher the concentration of glyceryl trioleate，the more obvious the changes；no normal cell was existed in glyceryl trioleate with concentration of 2 000 mg/dl. Effects of glyceryl trioleate on the proliferation of RASMC were in time and dose relationship. Glyceryl trioleate inhibited the proliferation of RASMC under the condition of 24 h and ≤125 mg/dl while glyceryl trioleate promoted the proliferation of RASMC under the conditions of 24 h and ≥250 mg/dl as well as 48-72 h and ≤ 500 mg/dl. Glyceryl trioleate reached the highest proliferation rate of 115.9% under the condition of 24 h and 1 000 mg/dl，significantly different from that in control group（t=-3.74，P=0.002）. Glyceryl trioleate inhibited the proliferation of RASMC under the condition of 48-72 h and >500 mg/dl as well as 96-144 h and 62.5-2 000 mg/dl. The proliferation rate decreased by 42.7% and 65% compared with those in control group（t=13.08，P=0.000）（t=129.53，P=0.000） under the condition of 24 h，72 h and 2 000 mg/dl. Flow cycle results revealed that G0/G1-phase percentage reduced in glyceryl trioleate group than in control group while percentage of S-phase increased in glyceryl trioleate group than in control group. Apoptosis percentage decreased in glyceryl trioleate group than in control group in every time point except 24 h and 144 h. The apoptosis rate was 1.1%（F=14.39，P=0.019） and 0.7%（F=9.96，P=0.034） in glyceryl trioleate group，statistically different from those in control group. In addi－tion，the changes of cell proliferation and apoptosis were in the same direction. Conclusion：The effect of glyceryl trioleate on the proliferation of RASMC is bidirectional：low concentration and short time as well as high concentration and long time exhibit inhibit－ing effect while moderate time and concentration exhibit promoting effect. The results of cell proliferation cycle also support the pro－moting or inhibiting effect of glyceryl trioleate on the proliferation of RASMC. The direct cytotoxic effect，induced cell proliferation or apoptosis of high concentration lipids may involved in the regulation of vascular smooth muscle cells number and function.