The Research Of The Effect Of Combination Of Selenium Dioxide And Cisplatin On The Human Ovarian Cancer Cells Xenografts In Nude Mice

Objective:To investigate the effect of the combination of selenium dioxide and cisplatin on the human ovarian cancer cells xenografts in nude mice, to analyze the expression of P-gp and apoptosis rate of the xenografts, and to preliminarily study the mechanism of decreasing the ovarian cancer's resistance with the combination of selenium dioxide and cisplatin .Methods:20 human ovarian cancer models were established by subcutaneously transplanting SKOV3/CDDP cells into nude mice,then xenografts to grow to 10mm×10 mm,then dividing them into control group and treated group. The latter includesDDP group:DDP 3 mg/kg 0.2ml+saline0.2ml;selenium dioxide group: selenium dioxide 30ug/0.2 ml+saline0.2ml;combination group: DDP 3 mg/kg 0.2ml+selenium dioxide 30ug/0.2ml. All of these medicines were injected intraperitoneally , once every three days , for four times in total. Then the transplantation rate,growth rate ,mean tumor inhibition rate and weight,appetite and mental state of the nude mice in different groups were observed. Tumor volume was measured after each injection to make a tumor growth curve. Flow cytometry was used to assess the characters of apoptosis in the tissues of the tumor. The expression of the P-gp was detected by immunohistochemistry.Results:The resistant ovarian cancers in all nude mice were grown successfully. The combination group most successfully inhibited the growth of the tumor and has statistic significance compared to other groups(P﹤0.05). Each group's mean tumor inhibition rates were41.69%,48.29%,72.28%. The combination group's tumor inhibition rate has statistic significance compared to the other group(sP﹤0.05). Each group's apoptosis rate detected by the flow cytometry is 5.2%,24.1%,25.9% ,45.43%, respectively,and the combination group significantly decreased the cancer cells in the S phase. It shows that the expression of P-gp in group 2 and 3 is lower than group 1 and control group(P﹤0.05).The positive expression of P-gp in each group is 59.85%,50.41%,35.67%,22.33%.Conclusions:1. The combination of selenium dioxide and cisplatin could inhabit the growth of resistant ovarian cancer.2. Selenium dioxide could increase the sensitivity of the resistant ovarian cancer to cisplatin and decrease the side effect of the chemotheraphy.3. Selenium dioxide and cisplatin have a synergistic effect on inducing the apoptosis of the resistant ovarian cancer cells.4. selenium dioxide could decrease the expression of P-gp . This may be one of the mechanisms to explain why selenium dioxide could increase the sensitivity of the resistant ovarian cancer to cisplatin.