低剂量X射线诱导小鼠胸腺细胞蛋白质表达及生物活性

Expression of proteins in mouse thymocytes induced by low dose X-rays and their biological activity

目的 :观察低剂量X射线照射的昆明小鼠胸腺细胞蛋白质表达及生物活性。方法 :采用SephadexG- 10 0凝胶过滤和高效液相分析 75mGy全身照射组和假照射组小鼠胸腺细胞蛋白质的表达 ,通过小鼠脾淋巴细胞转化和人外周血淋巴细胞染色体畸变检测蛋白质表达的生物活性。结果 :高效液相分析发现胸腺细胞 2 4 5kD蛋白质照射组明显低于假照射组 ,这种降低的蛋白质组分在终浓度为 6 2 5mg/L时 ,对ConA刺激正常小鼠脾淋巴细胞转化和X射线损伤人外周血淋巴细胞所致染色体畸变分别具有抑制和保护作用。结论 :低剂量辐射兴奋效应可能与2 4 5kD蛋白质的表达下调有关。

AIM: To observe the expression of proteins induced by whole-body irradiation in mice with low dose X-rays and their biological activity. METHODS: To analyse the expression of protein induced by whole-body irradiation with 75mGy X-rays and sham-irradiation, the method of gel filtration with Sephadex G-100 and HPLC were used. The biological activity of protein expressed in thymocytes was observed by mouse splenocyte proliferation and chromosome aberration of human peripheral blood lymphocytes. RESULTS: HPLC analysis showed that there was a marked decrease in expression of 24.5 kD protein molecule in the fractions of thymocyte extract in comparison with the corresponding fractions from the sham-irradiated control mice. These protein fractions from the thymocytes of the irradiated mice at the concentration of 6.25 mg/L showed both inhibitory effect on normal T cell proliferation and protective effect on the chromosome damage induced by high dose radiation. CONCLUSION: Down regulation of 24.5 kD protein molecule expression may have implications in the mechanism of immunoenhancement and cytogenetic adaptive response induced by low dose radiation.