Initial Practical Study Of CS-PAA-EPI Polymer Magnetic Microspheres On Bladder Cancer Targeting Chemotherapy

Objective:To prepare a new magnetic macro-molecular polymer,CS-PAA-EPI polymer magnetic microspheres,examine its characterization,body distribution, toxicity and study its effects on bladder cancer in vivo and in vitro,then evaluate its applied value on bladder cancer chemotherapy.Methods: 1 Stable chitosan-poly(acrylic acid) (CS-PAA) polymer magnetic microspheres were synthesized by polymerization of AA in CS solution in the presence of negatively charged magnetite nanoparticles. These polymer magnetic microspheres have a high Fe₃O₄ loading content. The characterization of the polymer,loading rate and embedding ratio were confirmed by FT-IR,TEM,DLS,zeta potential.2 Under the intension of magnet, EPI concentration. in rat plasma and some organs at different time was examined by high performance liquid chromatography, which was used to evaluate the effect of CS-PAA-EPI polymer magnetic microspheres targeting;to observe the difference of CS-PAA-EPI polymer magnetic microspheres distribution in treatment group and control group rat's plasma,kidney,spleen,liver,bladder and heart,we perform iron stain; we study different dose of CS-PAA-EPI polymer magnetic microspheres' toxicity by examining rat's blood routine examination,kidney function,liver function,blood glucose and electrocyte after intravenous injection from rat tail vein.3 The human bladder cancer T24 cell lines were divided into control group,epirubicin group,high,middle,low dose of CS-PAA-EPI group and CS-PAA group,the last 4 groups were combined with constant external magnetic field. The growth inhibiting rate of T24 cell lines were detected by MTT methods, apoptosis of cells were detected by flow cytometry, the mechanism of apoptosis was analyzed by detecting the protein expression of Bcl-2, Bax, Caspase-9, Caspase-3 and cytoplastic protein Cytochrome C. 4 We injected live T24 cells into the subcutaneous space of nude mice and successfully built up the animal model of bladder carcinoma. The effect of CS-PAA-EPI polymer magnetic microspheres targeting chemotherapy was investigated by HE staining, TUNEL ,tumor weight and volume inhibition rate.Results: 1 TEM revealed that the CS-PAA polymer magnetic microspheres were regular spherical shape,the average diameter was 80nm in dry condition. By controlling the pH value of the medium,polymers had positive or negative zeta potential. VSM showed the CS-PAA polymer magnetic microspheres had superparamagnetic. The diameter of CS-PAA-EPI polymer magnetic microspheres were 200nm in solution by DLS examining,the embedding ratio was 20%,the EPI loading rate was 15%, which was higer than reported in other articles. 2 Raw eye observation found that the rat's bladder of treatment group was brown color,which meaned the aggregation of iron particles, compared with the control group, iron stain found iron particles were assembled in rat's bladder of the treatment group, the amount of iron particles in liver and spleen were less obviously. The results of HPLC proved the iron stain found again. The rat's kidney function was impacted in the 14th day after drug administration both in high dose of CS-PAA-EPI polymer magnetic microspheres group and epirubicin. 3 The high,middle,low dose of CS-PAA-EPI polymer magnetic microspheres on growth inhibiting rate were highly improved, and apoptosis was found in treatment group, Our results of Western blotting showed that cytochrome C was released from the mitochondria into the cytoplasm in the cells of the treatment group and the expression of the Bcl-2 protein decreased significantly, Bax protein changed little,the Caspase-3, Caspase-9 were activated. 4 The tumor weight and volume inhibition rate of the high,middle,low dose of CS-PAA-EPI polymer magnetic microspheres group were higher than those of the control group,which were also proved by HE stain and TUNEL.Conclusion: 1 CS-PAA-EPI polymer magnetic microspheres,with high EPI loading rate and superparamagnetic, is stable and fit for bladder cancer targeting chemotherapy. 2 In combination with constant external magnetic fields, CS-PAA-EPI polymer magnetic microspheres were targeted at rat baldder, which decreased the EPI distribution in other organs and the side effect of EPI. 3 The growth inhibiting rate of T24 cell lines were highly improved in treatment group,which was caused by the startup of cell apoptosis related to mitochondrion quick apoptotic pathway. 4 The effect of CS-PAA-EPI polymer magnetic microspheres targeting chemotherapy on bladder caner was much better than that of conventional chemotherapy. we believe targeting chemotherapy has a good application future in bladder caner therapy.