Correlations between ~(99)Tc~m-MIBI uptake and membrane potential of mitochondrion or lung resistant protein of tumor tissues

Objective To study the mechanism of 99 Tcm -MIBI examining the resistance of lung adenocarcinoma A549DDP cells. Methods The method of methoxyisobutylisonitrile (MTT) was applied to test IC_ 50 of cisplatin to A549 cells, to test IC_ 50 of cisplatin to A549DDP cells after dealing with or without micro dose of cisplatin. The cells above were all injected under the skin of nude mice to observe growth status of tumors. After setting up of the tumor models, the nude mice were performed using SPECT with 99 Tcm -MIBI. Lung resistant protein (LRP) of transplanted tumor cells were determined with immunohistochemical method. Membrane potential of mitochondrion (△Ψ) of the cells were measured by flow cytometry. Results IC_ 50 of cisplatin to A549 cells was 24 μM. That to A549DDP cells which did not deal with micro dose of cisplatin was 182 μM, and to A549DDP cells dealed with mecro dose of cisplatin was 325 μM. Tumors developed by reason of incepting 99 Tcm -MIBI in all mice. The R value in A549 mice was remarkably higher than that in A549DDP mice (P0.05). LRP in A549 cells from transplanted tumor did not express otherwise that in A549DDP cells strongly expressed. △Ψ of A549DDP cells dealt with micro dose of cisplatin were observably higher than that of both A549DDP cells which dealt without micro dose of cisplatin and A549 cells. Conclusion The mechamism of 99 Tcm -MIBI examine the resistance of lung adenocarcinoma A549DDP cells may correlate with both △Ψ of cells and expression of LRP of cells.