An Experimental Study On Irradiation-induced Mutation Type P53 And Bcl-2 Expressions In Orthotopic Human Gastric Carcinoma Cells And Mice Gastric Mucosa Cells

[Objective] To investigate the expressions of mutation type p53/bcl-2 in human gastric carcinoma and normal gastric mucosa before/after X-ray irradiation with the methods of immunohistochemical staining.[Materials and Methods] 21 BALB/c nude mice with orthotopic human gastric carcinoma were randomized into 3 groups, of which 7 mice in group A (control group), 7 in group B(group of 24 hours after irradiation) and 7 in group C (group of 48 hours after irradiation). The whole stomachs of nude mice including implanted tumor were irradiated with 6 MV X-rays at 20 Gy. The pathological changes of implanted SGC-7901GCC and normal mice gastric mucosa were examined by light microscop (LM) and transmission electron microscope (TEM) after ionizing irradiation. At the same time,using the methods of immunohistochemical staining (ABC), the expressions of mutation type p53/bcl-2 and the changes after ionizing irradiation were investigated in these two different tissues,respectively.[Results] The total success rate of the establishment of animal models with orthotopic implanted tumor is 100% (among which the figure is 85.7% for the first time). In group A (control group), the expressions of mutation type p53 and bcl-2 proteins can all be detected.The expression rates of mutation type p53 protein in gastric carcinoma cells and mice gastric mucosa cells are 61.11% and 20.39%,respectively; and the rates of bcl-2 protein are 38.89% and 16.5%, respectively. In group B (24 hrs after irradiation), the expressions of mutation type p53 and bcl-2 proteins can all be detected too. While the expression rates of mutation type p53 protein in gastric carcinoma cells and mice gastric mucosa cells are 40.28% and 15.53%,respectively; the rates of bcl-2 protein are 23.61% and 10.68%, respectively. In group C (48 hrs after irradiation), the expressions of mutation type p53 and bcl-2 proteins can also be analyzed. While the expression rates of mutation type p53 protein in gastric carcinoma cells and mice gastric mucosa cells are 22.22% and 10.68%, respectively; the rates of bcl-2 protein are 13.89% and 5.83%, respectively.[Conclusion] 1 . The positive expression rates of mutation type p53 and bcl-2 proteins in implanted tumor cells are significantly higher than those in normal gastric mucosa cells, which maybe suggest the p53 mutation/bcl-2 protein is probably one of the multi- genes/ multi- reasons of/for the occurance and development of the gastric carcinoma. 2. X-ray irradiation induces apoptosis in gastric carcinoma cells and mice gastric mucosa cells, in the mean time the expression rates of mutation type p53 and bcl-2 proteins reduce. So we can refer that the inducement works through p53 and bcl-2.