Besides, the body weights of mice were not affected by the 125I irradiation

and no obvious radiation-induced damage was observed in vital organs of mice (data not shown), indicating the safety of 125I seed treatment. Figure 1 Effect of 125I seed irradiation on the tumor volume and tumor weight. (A) Tumor volumes. (B) Tumor weight. Data are the mean ± SD and analyzed by the Mann–Whitney U test (☆: P < 0.05). Effect of 125I seed irradiation on tumor morphology of gastric cancer To investigate the effect of 125I irradiation on the histology of NCI-N87 xenografts, tumor sections taken from mice in the control and 125I treatment groups were stained with H&E. As shown in Figure 2, the histologic appearance of tumors in the Ku-0059436 cost control group was quite different from that in the 125I treatment group. In the control group, the cancer cells were densely arranged with large darkly-stained nuclei and obvious karyokinesis. In the treatment group, large necrotic regions were observed around the 125I seed. The cancer cells adjacent Torin 1 price to the necrotic region were loosely arranged with condensed nuclei and reduced eosinophilic cytoplasm. These results indicated that 125I seed implantation caused growth inhibition of cancer cells in NCI-N87 xenografts. Figure 2 Pathology of 125 I implanted gastric cancer. Representative HE stained sections from the control and 125I treatment groups 28

d after 125 I seed implantation were prepared as described in the Materials 6-phosphogluconolactonase and Methods section. Effect of

125I seed irradiation on cell apoptosis and mitosis of gastric cancer To quantitatively compare the mitotic and apoptotic index of tumors treated with 125I seed irradiation, immunostainings for PCNA and TUNEL assays were performed. As shown in Figure 3A, the number of PCNA- positive cells in the 125I treatment group was obviously less than that of control group. And the mitotic index was significantly decreased in irradiated tumors as compared to the tumors in the control group Figure 3B). In contrast to the mitotic index, 125I-irradiated tumors showed increased numbers of apoptotic cells with condensed and irregularly shaped nuclei, staining positively for TUNEL Figure 3 C). the apoptotic index was significantly increased in the 125I treatment group as compared to the control group Figure 3D). Figure 3 PCNA and TUNEL analyses for tumor tissue. (A) Tumor sections immunostained with an antibody against PCNA revealed that there were many strongly positive nuclei in control tumor tissues, whereas such nuclei were rare in tumor tissues of 125I treatment group. (B) Quantification of PCNA staining showed mitotic index of 125I-implanted tumor was much lower than that of control group (☆: P < 0.05). (C) Apoptosis of tumor tissues in different groups were evaluated by TUNEL assays, which showed that 125I treatment induced a significant enhancement of apoptotic cells in contrast to control group.