ABSTRACT
Objective:To investigate the effect of antlerbase on the radiation carcinogenesis by observing the effect of antlerbase on the expressions of Notch2 gene and immune function of the mice with thymic lymphomas induced by ionizing radiation.Methods:Ninety BALB/c mice were randomly divided into control group,irradiation group and irradiation combined with drug group (combined group)(n=30).The thymic lymphoma models of mice were made by X-ray irradiation in irradiation group and combined group;after establishing the animal models,the mice in combined group were fed with chow containing antlerbase superfine powder.After 6 months,the whole blood and thymic tissue were taken,then RT-PCR and Western blotting methods were used to detect the mRNA and protein expressions levels of Notch2 gene in the thymic lymphoma tissue;ELISA method was used to detect the serum immunoglobulin (IgG,IgA,IgM)levels and SOD kit was used to detect the serum SOD activities of the tumor mice.Results:The incidences of thymic lymphoma in irradiation group and combined group were 53.33%(16/30)and 36.67% (11/30),respectively.Compared with control group,the expression levels of mRNA and protein of Notch2 gene in thymic lymphoma of the mice in irradiation group were significantly increased (P <0.05);compared with irradiation group,the expression levels of mRNA and protein of Notch2 gene in combined group were decreased (P <0.05);compared with control group,the levels of IgG,IgA,and IgM in serum of the mice in irradiation group were decreased (P < 0.05 ); compared with irradiation group, the levels of IgG, IgM, hemoglobin and the activity of SOD in serum of the mice in combined group were increased (P < 0.05 ). Conclusion:Ionizing radiation can activate the high expression of Notch2 gene and protein and decrease the immune function of mice,it might be one of the mechanisms for the occurrence of radiation carcinogenesis;antlerbase can decrease the incidence of radiation carcinogenesis by inhibiting the expression of Notch2 gene and increasing the immune function of mice,which might play an role in restraining tumor.
ABSTRACT
Objective To study the changes of mRNA and protein expressions of Kras gene in thymic lymphomas induced by ionizing radiation,and to detect the methylation of CpG islands in promoter region of Kras gene,then to investigate the mechanisms for the occurrence of radiation carcinogenesis.Methods The thymic lymphoma models of BALB/c mice were made by X-ray irradiation,then the total RNA was extracted,cDNA was synthesized and the total protein was extracted from both thymic lymphoma tissue and normal thymus tissue;the mRNA and protein expressions of Kras gene in thymic lymphoma tissue and normal thymus tissue were detected by RT-PCR and Western blotting method, and the methylation of CpG islands in promoter region of Kras gene was detected by bisulfite sequencing PCR. Results The mRNA expression level of Kras gene in thymic lymphoma tissue was significantly higher than that in normal thymus tissue(P<0.01).The protein expression level in thymic lymphoma tissue was about 1.41 times higher than that in normal thymus tissue;4 CpG sites were methylated detected by bisulfite sequencing PCR in normal thymus tissue, however, 1 CpG site was methylated in thymic lymphoma tissue,the CpG islands in promoter region of Kras gene were demethylation state in thymic lymphoma. Conclusion Ionizing radiation can cause the changes of mRNA and protein expression levels of Kras gene in thymic lymphoma tissue by demethylation state of Kras gene,eventually lead to the occurrence of tumor;it might be one of the mechanisms for the occurrence of radiation carcinogenesis.