Objective Carboplatin（CBP）-resistant cell line（Tca8113/CBP） and pingyangmycin（PYM）-resistant cell line（Tca8113/PYM） were established in vitro. Ginkgolic acids’influence over multidrug resistance（MDR） of drug-resistant cells was discussed by ginkgolic acids coupled with chemotherapy drugs. Methods The expression of P-glycoprotein（P-gp） was detected by immunohistochemistry. MTT assay was applied to ascertain the resistance index of drug-resistant cells. The effect of different concentrations of ginkgolic acids on the proliferation of drug-resistant cells and parental cell was measured by MTT assay. Making sure the non-toxic concentration of ginkgolic acids and observing the reversal effect of ginkgolic acids on drug-resistant cells. Resistance index was redetermined by MTT assay after ginkgolic acids coupled with chemotherapy drugs induced the cell lines for some time. Results Immunohistochemistry showed that P-gp positive expression rate of drug-resistant cells was significantly higher than parental cells. The non-toxic concentration of ginkgolic acids which was determined by MTT assay was 10 μg·mL-1. The reversal folds of Tca8113/CBP cell line to CBP and Tca8113/PYM cell line to PYM were 2.94 and 2.43 respectively. Before coupled with ginkgolic acids, the resistance indices of Tca8113/CBP and Tca8113/PYM cell lines were 3.24 and 11.9 respectively. When ginkgolic acids was added with chemotherapy drugs for some time, the resistance indices of Tca8113/CBP and Tca8113/PYM cell lines were 2.18 and 4.43 respectively. Conclusion This experiment successfully induced the drug-resistant cell lines of Tca8113/CBP and Tca8113/PYM. The method of chemotherapy drugs coupled with ginkgolic acids further confirmed the effect on proliferation of Tca8113/CBP and Tca8113/PYM cell lines was reducing. Non-toxic concentration of ginkgolic acids can partially reverse the drug resistance of Tca8113/ CBP and Tca8113/PYM cell lines. Furthermore, MDR level of drug-resistant cells decreased somewhat when they were induced by ginkgolic acids coupled with chemotherapy drugs for some time.
