The Effect Of ¹²⁵I Seeds Interstitial Brachytherapy For Human Laryngocarcinoma Xenograft In Nude Mice

ObjectiveThis study aimed to examine the effect of 125I seeds interstitial brachytherapy for human laryngocarcinoma xenograft in nude mice and to determine underlying mechanisms involved.The effect of iodine-125 seeds on apoptosis and proliferation of human laryngocarcinoma xenograft was investigated to provide a reference for clinical treatment.MethodsTU212 laryngocarcinoma cell suspension was used to establish tumor-bearing mice model.The model was reared for approximately 3 weeks and then randomly divided into the control group(implanted with sham seeds)and the experimental group(implanted with 0.8mCi seeds).Two 125I seeds were respectively implanted by 18G implant needle in each nude mouse xenograft with the guidance of CT.The treatment planning system(TPS)was used for preoperative planning design and postoperative planning verification.The tumor volume was recorded every three days till the end of study.After 30 days of treatment,all mice were humanely sacrificed,and tumors were harvested and weighed followed by fixed in 4%paraformaldehyde(PFA)or flash frozen on liquid nitrogen.Tumor sections were stained using hematoxylin-eosin(HE)to investigate the histology.The relative mRNA expression of Bax、Bcl-2、Ki67、PCNA was assessed by qPCR.The relative protein expression of Bax、Bcl-2、PCNA was assessed by western blot analysis.Immunohistochemistry(IHC)was also used to assess the relative protein expression of Bax,Bcl-2,Ki67,PCNA.Results(1)After implantation of 125I seeds,the volume and weight of tumor in experimental group was significantly smaller than that in control group(P<0.05).(2)The histological appearance of the tumors showed that the cancer cells were densely arranged with large darkly stained nuclei in control group and obvious karyokinesis with broad necrosis in experimental group.(3)qPCR results:The relative mRNA expression of Bax in experimental group was significantly higher than that in the control group(P<0.05),while the expression of Bcl-2,Ki67 and PCNA in experimental group were significantly lower than that in the control group,respectively(all P<0.05).(4)Western Blot results:The relative protein expression of Bax in experimental group was significantly higher than that in the control group(P<0.05),while the expression of Bcl-2 and PCNA in experimental group was significantly lower than that in the control group,respectively(all P<0.05).(5)Immunohistochemistry results:Expression of Bax in experimental group was significantly higher than that in control group(P<0.05),while the expression of Bcl-2,Ki67 and PCNA in experimental group was significantly lower than that in control group,respectively(all P<0.05).Conclusion125I seeds interstitial brachytherapy has a significant anticancer effect on human laryngocarcinoma xenograft in nude mice.Promoting tumor cell apoptosis and inhibiting tumor cell proliferation may be its main mechanism involved.