The Influence Of Interstitial Brachytherapy With ¹²⁵I Seeds On Caspase-3 And Egr-1 Expressions Of Lewis Lung Carcinoma In C57BL Mice

Objective: To explore the influence of interstitial brachytherapy with ¹²⁵I seeds on Caspase-3 and Egr-1 expressions of Lewis lung carcinoma in C57BL mice.Methods: Lewis lung cell (LLC) was planted into model mice of C57BL and were divided into the treatment group(n=20)and the control group(n=20). In each mouse of the treatment group, two BT-125-1 Model ¹²⁵I seeds with apparent activity of 9.25 MBq were implanted into the tumor; whereas in each mouse of the control group two dummy seeds were implanted. The mice survival rates of both groups were recorded after 21 days. The tumor weights and dimensions of survived mice were measured, and the tumor volume inhibition rate was calculated. T-test was performed to compare differences of tumor weights and volumes between these two groups. Routine pathological slides of tumor tissue were observed under light microscope. The expression of Caspase-3 was detected by immunohistochemical method and the expression of Egr-1 was detected by RT-PCR method.Results: The survival rates were 85% in the treatment group and 70% in the control group, the difference had no statistical significance(P>0.05). The tumor volume inhibition rate was 71.12%. Pathological examination showed degeneration and necrosis of cancer cell at the site nearby the seed in the treated group, but the tumor cells alive were still presented nearby the seed in the control group. The expressions of Caspase-3 and Egr-1 in the treated group were highter than those in the control group(t=12.825,P<0.01; t=7.039,P<0.01;respectively). Conclusion: The interstitial brachytherapy with ¹²⁵I seeds could significantly inhibit the growth of Lewis lung cacinoma of mice. The possible mechanism may be that ¹²⁵I interstitial brachytherapy can enhance the expressions of Egr-1 and Caspase-3, which could induce tumor cellular apoptosis.