Effects Of Selenium On Genetic Damage Induced By Mitomycin-C In Human Peripheral Lymphocytes

OBJECTIVE: Selenium is an essential micronutrient. It is well known that selenium has many roles, such as, it appears to be a key nutrient in resisting oxidation and senescence, strengthening the function of the immune system, and preventing from cardiovascular disease. Especially in the past few years, the relationship between selenium and cancer has become the great interest of people 。But from the viewpoint of genotoxicity, selenium is still not studied fully. The aim of this study is to access the effects of selenium on MMC-induced DNA damage in human peripheral lymphocytes, and DNA damage, discussing the genotoxic related to selenium, providing the theory base for selenium applying in clinical medicine. METHODS: From different aspects,this paper access the effects of selenium on the DNA damage and chromosome damage induced by MMC using single cell gel electrophoresis(SCGE) ,sister chromatid exchange(SCE) and chromosome aberrations(CA), and compared the sensitivity of whole blood with that of the separating lymphocyte from the blood in comet assay. RESULTS: 1.The tail length, SCE frequencies and the chromosomal aberration rate of three dose of selenium were lower significantly than that of the positive control, furthermore, the extent of DNA damage of Group medium dose of selenium (6μmol/L) was lower than the other Groups. 2. In genotoxic test, selenium can induce the significant increase of tail length, SCE frequencies and the chromosomal aberration, and it showed a dose-dependent increase. 3. In comet assay, lymphocyte tail length of Group low dose of selenium (1μmol/L) was significantly higher than the negative control. In the SCE and chromosomal aberration, SCE frequencies and the chromosomal aberration rate of only Group medium dose and high dose of selenium (6 and 10μmol/L) was significantly higher than the negative control. 4. In comet assay, there was no significant difference between whole-blood and isolating lymphocytes from blood. CONCLUSIONS: 1. To some extent, selenium can protect DNA from damage induced by MMC. The protective role of medium dose of selenium (6μmol/L) is stronger than the other groups. 2. Selenium induced the increase of DNA damage, SCE frequencies and chromosomal aberration, because high dose of selenium can promote DNA oxidation. It showed some genotoxic. 3. From different genetic aspects, SCGE, CA and SCE detected the protective role of selenium on DNA damage induced by MMC, and the results showed that SCGE was more sensitive. 4. In comet assay, DNA damage induced by MMC can be detected by the method both of whole-blood and isolating lymphocytes from blood. The results of two methods were similar and the sensitivity was equal .In addition, the operation of whole-blood is simple and direct, and it needs little blood, therefore it is easier to be accepted by people and suitable for large-scale screen and people monitoring.