Effect Of Cyclic Stretch On Apoptosis Rate And Apoptotic Gene Expression Of Human Oral Squamous Cell Carcinoma KB Cells

The mechanical environment affect the proliferation, differentiation, genetic material transfer, genic mutation and other biological effect of organism. The mechanical stress affect the function and growth of tissues and organs, the proliferation, differentiation, apoptosis and metabolism of cells by the mechanics-biology signal transformation. In the oncology research, The mechanical forces affect the proliferation, differentiation, apoptosis and metastasis of tumor cells. The studies, the biological effects and mechanism of the mechanical forces on the cancer cells, is still in the initial stage. In order to investigate the effects of mechanical forces on the tumor cells, and the mechanism of cyclic stretch on apoptosis of tumor cells, Human oral Squamous Cell Carcinoma KB Cells were used in this experiment. The effects of cyclic stretch on apoptosis rate and apoptotic gene expression of Human oral Squamous Cell Carcinoma KB Cells were studied by FX-4000strain unit, the apoptosis rates were examined and analyzed by flow cytometry, the mRNA expression of Bcl-2、Bax and caspase-3were examined by Real-time fluorogenic quantitative polymerase chain reaction (RFQ-PCR). The results were compared with the effects of the cis-platinum on the KB cells.Main content and conclusions are following:1. The effects of cyclic stretch on KB cells:KB cells were Inoculated on six-hole culture plates (the base of these culture plates consists of a flexible). The cells were cultured24h before experiment of cyclic stretch, experimental regimen:square wave with10%,15%elongation amplitude,24h duration, and with frequency0.5Hz. Cells plated on Bioflex plates but not subjected to stretch served as controls for each group. After mechanical stretch, the apoptosis rates were examined and analyzed by flow cytometry, the mRNA expression of Bcl-2、Bax and caspase-3were examined by RFQ-PCR. The results:Under the stretching culture of different cyclic stretch regimens by FX-4000Tension System, the apoptosis rate was increased significantly compared with the control group (P<0.05), the apoptosis rate of15%group was significantly higher than10%group (P<0.05); the expression of Bcl-2mRNA was reduced significantly compared with the control group (P<0.05), the expression of Bcl-2mRNA of15%group was significantly lower than10%group (P<0.05); the expression of Bax mRNA and Caspase-3mRNA were increased significantly compared with the control group (P<0.05), the expression of Bax mRNA and Caspase-3mRNA of15%group was significantly higher than10%group (P<0.05).2. The effects of cis-platinum on the KB cells:The KB cells was treated by the low-dose cis-platinum. There was no different of the apoptosis rate of the cells, which was treated by the1μg/ml cis-platinum after12h, when compared with the control group (P>0.05), after24h, the apoptosis rate was increased significantly (P<0.05). The apoptosis rate of the cells, which was treated by the4μg/ml cis-platinum after12h and24h, was increased significantly (P<0.05).The experimental results show that:1. The cyclic stretch promoted the apoptosis of the KB cells, the apoptosis rate of the15%group was higher than the10%group.2. The cyclic stretch changed the mRNA expression of Bcl-2、Bax and caspase-3, the effects of the the15%group was more significant than the10%group.3. The apoptosis rate of10%group cells was lower than the cells which was treated by the4μg/ml cis-platinum after24h. There was no different of the apoptosis rate of the15%group cells when compared with the cells which was treated by the4μg/ml cis-platinum after24h.