Study On The Reversal Effect Of Shengmai Injection Down-regulating The Expression Of P-glycoprotein On Helicobacter Pylori Lipopolysaccharide Induced Multidrug Resistance Of Gastric Cancer Cell

Objective:To explore the effect of Helicobacter pylori lipopolysaccharide（Hp-LPS）on the multidrug resistance（MDR）of gastric cancer（GC）cell line SGC7901;to explore the reversal effect of Shengmai injection（SMI）on SGC7901 cells induced by Hp-LPS.Methods:1.Cultivate H.pylori,and extract Hp-LPS after being identified by urease test and peroxidase test.2.CCK-8 assay was used to determine the IC₅₀values??of 5-fluorouracil,cisplatin and doxorubicin,and proceed to the next experiment.3.CCK-8 assay was used to determine the OD₄₅₀value of the co-cultured Hp-LPS and SGC7901 cells at different time points,draw the growth curve,select the appropriate Hp-LPS concentration,and proceed to the next experiment.4.CCK-8assay was used to determine the MDR effect of Hp-LPS on the SGC7901 cells.5.CCK-8 assay was used to determine the cytotoxicity of SMI,and the non-toxic concentration was selected for the next experiment.6.CCK-8 assay was used to determine the effect of non-toxic concentration of SMI on reversing the MDR SGC7901 cells induced by Hp-LPS.7.Flow cytometry assay was used to analysis the effect of SMI on the apoptosis of SGC7901 cells induced by Hp-LPS.Results:1.Small or needle-like translucent hemispherical colonies can be seen on Columbia culture medium,which can be identified as H.pylori after urease test and peroxidase test.2.5-Fluorouracil,cisplatin,and doxorubicin can inhibit the proliferation of SGC7901 cells with a time-effect and dose-effect relationship.IC₅₀values??are 27.77±4.43μM,2.97±0.65μM,0.32±0.02μM,respectively.3.The co-culture growth curve showed that when the concentration of Hp-LPS was 1μg/ml,it has the closest correlation with the control group,so this concentration is selected.4.Hp-LPS can reduce the inhibitory rate of 5-fluorouracil,cisplatin,and doxorubicin on SGC7901 cells.5.SMI can inhibit the proliferation of SGC7901,and has a time-effect and dose-effect relationship.When the concentration of SMI is 50μl/ml,the cell inhibition rate does not exceed 10%,which can be regarded as a non-toxic concentration.6.SMI can increase the sensitivity of multidrug resistant cells induced by Hp-LPS to 5-fluorouracil,cisplatin and doxorubicin,and overcome the MDR.The relative reversal multiples are 1.76,1.46 and 1.60.7.The flow cytometry assay showed that Hp-LPS can inhibit the apoptosis of SGC7901 caused by 5-Fu,and SMI can promote the apoptosis of SGC7901 cell line after the intervention of Hp-LPS.The apoptosis index of the control group,5-Fu group,LPS group and Shengmai group were 6.8±1.26,42.1±0.73,31.7±1.01 and 38.2±0.85,respectively.Conclusion:This experiment proves that Hp-LPS can reduce the inhibitory rate of a variety of chemotherapeutic drugs on SGC7901 cells,promote the proliferation of GC cells,inhibit apoptosis,and induce MDR;this experiment also proves that the non-toxic concentration of SMI can enhance the inhibition rate of SGC7901 cells induced by Hp-LPS and promote apoptosis,playing a role in reversing multi-drug resistance.