Killing effect and molecular mechanism of ~(125)I seeds interstitial brachytherapy on human hepatocarcinoma cell HepG2 of transplanted tumor in nude mice / 中国介入影像与治疗学

ABSTRACT

Objective To investigate the killing effect and molecular mechanism of different doses of ~(125)I seed interstitial brachytherapy for human hepatoma HepG2 cells in nude mice transplanted tumor.Methods Twenty nude mice bearing human hepatoma HepG2 cells were randomly divided into 4 groups (each n=5) and given ~(125)I seed interstitial brachytherapy at different doses including 18.5 MBq ~(125)I,29.6 MBq ~(125)I,37.0 MBq ~(125)I and 0 (the control group) ,respectively.~(125)I seeds were percutaneously implanted into tumors,each mouse with 1 ~(125)I seed implanted.Twenty-eight days later,nude mice were sacrificed and routine pathological examination was performed,.The expression of Bcl-2 and Bax was detected with immunohistochemical methods.Results Pathological examination showed serious coagulation necrosis of tumor cells surrounded by extensive fibrosis in all treatment groups,whereas rich tumor cells with proliferative growth were observqed in the control group.Immunohistochemical analysis showed that the expression of Bax in all treatment group were higher than that in the control group.the expression of which was up-regulated with increasing doses of ~(125)I seed.The expression of Bcl-2 and the ratio of Bcl-2/Bax in all treatment groups were lower than those in the control group.the expression of which was down-regulated with increasing doses of ~(125)I seed.The expression of Bcl-2.Bax and the ratio of Bcl-2/Bax among treatment groups and control group had statistical difference (P＜9.05) ,so as the difference among treatment groups (P＜0.05) .Conclusion ~(125)I seed interstitial brachytherapy induces apoptosis in human hepatoma HepG2 cells by reducing the ratio of Bcl-2/Bax and thereby inhibits the growth of tumor in nude mice,and the extent positively correlates with dosage in a certain range.