Influences Of Cisplatin On Expressions Of P-glycoprotein In The Resistance Cells Of In Lung Cancer Xenografts In The Mice

Objective:To investigate the effect of the cisplatin on the resistance cells of Lewis lung cancer xenografts in mice, to analyze the expression of P-gp and growth inhibition rate of the xenografts,and by approach the relation of the the expression of P-gp and cisplatin.Methods:The C57BL/6 mice were used to the experimental animals.The resistance cells of Lewis lung cancer were cultured,and collected the tumor cells in logarithmic growth phase.The concentration of cell suspension was adjusted to 1x107/ml.The resistance cells of Lewis lung cancer models were established by subcutaneously transplanting the cells into the left hind leg of the mice,then xenografls to grow to 10mm x 10mm.The mice were extracted the ten from the forty mice randomly.The expression of the P-gp was detected by immunohistochemistry.The other tumor-bearing mice were divided of thirty into saline group and cisplatin group.The saline group:saline0.2ml;the cisplatin group:DDP lml/mg 0.2ml. All of these medicines were injected intraperitoneally, once every two days, for four times in total. Then the transplantation rate,growth rate, mean tumor inhibition rate and weight, appetite and mental state of the mice in different groups were observed. Tumor volume Was measured after each injection to make a tumor growth curve. The expression of the P-gp was detected by immunohistochemistry.Results:The resistant cells of Lewis lung cancer in all mice were growning successfully.The positive expression of P-gp before treatment is 20%. The positive expression of P-gp in saline group is 20%. The positive expression of P-gp in cisplatin group is 33.3%. The cisplatin group successfully inhibited the growth of the tumor and has statistic significance compared to saline groups (P<0.05).Cisplatin group's mean tumor inhibition rates were 31.29%.It showed that the expression of P-gp in cisplatin group was higher than that of saline group(p<0.05).Conclusions:The cisplatin could inhabit the growth of the resistant cells of Lewis lung cancer.Cisplatin could increased the expression of P-gp.Cisplatin resistance had weakened the inhibition of lung cancer in mice.P-gp may be one of the molecular markers to explain why the resistance of cisplatin could predict the therapy of lung cancer.