Effect Of Ultrasound On The Chemotherapeutic Sensitivity Of SK-N-SH Cell And Its Mechanisms

PART ONEEffect of ultrasound on the survival rate of SK-N-SH cellObjective To observe the effect of ultrasound of various times on the survival rates of SK-N-SH cells. Methods The survival rates of SK-N-SH cell were assessed by MTT assay after the cells were exposed to the ultrasound of various times (10s-100s). Results The survival rates of SK-N-SH cell decreased from 99% to 11% after various dosages of ultrasound irradiation,the longer the exposure time, the lower the survival rate. The survival rates of SK-N-SH cell were more than 90% when the irradiation time was less than 40 second. Conclusion The ultrasound has cytotoxic effect to SK-N-SH cell; there is a significant dose-effect relationship between irradiation time and the survival rate of cell. The irradiation time used in the next experiment is 40 second. PART TWOEffect of ultrasound on the chemotherapeutic sensitivity of SK-N-SH cell and its mechanismsObjective To research the effect of ultrasound on the chemotherapeutic sensitivity of SK-N-SH cell and discuss its mechanisms. Methods 1. The SK-N-SH cells were divided into experimental group and control group, the experimental group include VCR and VCR+U group. In VCR group, the cell suspensions were received sham irradiation after adding VCR of different concentration; In VCR+U group, the cell suspensions were received ultrasound irradiation after adding VCR of different concentration. MTT assay was used to assess the survival rates of SK-N-SH cells in different groups. 2. Observe the changes of structure of SK-N-SH cells exposed to ultrasound or sham irradiation by scanning electron microscope. 3. Detect the expression of P-gp in SK-N-SH cells exposed to ultrasound or sham irradiation by immunocytochemistry assay. Results 1. The survival rates of SK-N-SH cells in VCR+U group are lower than in VCR group. 2. In the pictures of SK-N-SH cells took by scanning electron microscope, we can see: there are some holes of different diameter on the cell membrane and the numbers of microvillus reduce or disappear after ultrasound irradiation. 3. The expression of P-gp in SK-N-SH cells exposed to ultrasound is lower than the cells exposed to sham irradiation. Conclusion 1.Ultrasound can enhance the cytotoxic effect of VCR to SK-N-SH cell. 2. Ultrasound can damage the structure of cell membrane of SK-N-SH cell. 3. Ultrasound can reduce the expression of P-gp in SK-N-SH cells, which means ultrasound can reverse the MDR of tumor cell.Conclusions1. The ultrasound has cytotoxic effect to SK-N-SH cell, the longer the exposure time, the lower the survival rate. There is a significant dose-effect relationship between irradiation time and the survival rate of cell.2. The survival rates of SK-N-SH cell were more than 90% when the irradiation time was less than 40 second. We chose 40 second as the irradiation time in the next experiment.3. Ultrasound can enhance the cytotoxic effect of VCR to SK-N-SH cell.4. The mechanisms of ultrasound enhancing the chemotherapeutic sensitivity of SK-N-SH cell are as follows:⑴Ultrasound can damage the structure of cell membrane of SK-N-SH cell:①there are some holes of different diameter on the cell membrane, which means ultrasound can increase the permeability of cell membrane;②the numbers of microvillus reduce or disappear after ultrasound irradiation.⑵Ultrasound can reduce the expression of P-gp in SK-N-SH cells, which means ultrasound can reverse the MDR of tumor cell.