| Objective: To extract the reversal of multidrug resistance active constituent of Caulis Mahoniae and study the reversal effect and reversal mechanisms of active constituent on the reversal of multidrug resistance(MDR).Methods: The accumulation of rhodamine123 (Rh123) were detected in K562/ADM cells by the high content screening (HCS). MTT assay was used to determine the cytotoxicity of active constituent alone and active constituent combined with adriamycin(ADM) on human leukemia multidrug resistance cells. Rhodamine 123 and ADM accumulation experiment was used to determine the effect of active constituent on p-glycoprotein(P-gp) function in K562/ADM cells by the high content screening (HCS). PI/Hochest 33342 was used to determine the apoptosis of active constituent by ADM in K562/ADM cells by the high content screening (HCS). The effect of active constituent on the transcription of MDR1 gene was determined by semiquantitative RT-PCR analysis.Resusts:1. From Caulis Mahoniae extract screening K562/ADM 6 kinds of membrane can inhibit the function of P-gp active ingredients, of which the most active of DMAG.This study is to examine the reversal effect and reversal mechanism of DMAG in doxorubicin-resistant human leukemia K562 cells.2. Inhibitory rates of 0.1μmol/L DMAG for K562 and K562/ADM cells was under 10%, so this concentration was regarded as innocuous dosage of DMAG. Under this dosage(0.01μmol/L,0.02μmol/L,0.04μmol/L,0.08μmol/L,0.1μmol/L),reversal fold of DMAG on K562/ADM cells was respectively 3.17,3.99,5.01,6.14,6.45, the reversing effect of DMAG on multidrug resistance was higher than that of Verapamil.3. Comparing with sensitive cell lines,the ADM fluorescene was sharply decreased in multi-drug resistance cells by the high content screening (HCS) and after exposing DMAG to restored the abnormal distribution of ADM in leukemic cell lines and reversed MDR.4. DMAG increased the intracellular accumulation of Rh123 in a concentration-dependent manner in K562/ADM cells. But it had no effect on K562 cells. 5. DMAG increased the apoptosis induced by ADM in K562/ADM cells.6. DMAG down-relagulated the over-expression of MDR1 in a concentration-dependent manner.Conclusions:1.The credit of DMAG extracted from Caulis Mahoniae had the revesal effect significantly.2. DMAG not only inhibited the efflux function of P-gp and increased the drug concentration, but also enhanced the apoptosis induced by anticancer drugs and down-relagulated the over-expression of MDR1 gene in K562/ADM cells. |
