Biodosimetry of UV radiation through the detection of cytogenetic endpoints in Allium cepa meristems

In this study, we examined the response of Allium cepa sprout stem cells, or meristems, to UVB and UVC radiation. The choice of Allium cepa, or onion, was made to avoid the controversial use of animal models. Allium cepa is a well-established in vivo standard model that is frequently used in cytogenetic research connected to various environmental contaminants. Indicators such as micronuclei and chromosomal abnormalities were used to evaluate the genotoxicity of UVB and UVC radiation, and the mitotic index was used to investigate the cytotoxicity of the radiation, providing information on cellular proliferation. The Shapiro-Wilk test (p < 0.05) confirmed the normality of the data. The analysis of the Pearson linear correlation coefficient (r = 0.97), conducted across all dose points considered, including the negative control, revealed an almost perfect positive linear relationship between the dose and the number of cells with micronuclei, for both UVB and UVC. The frequency of induction of micronuclei as a function of dose for both radiation types was found to be similar. However, a difference in the morphology of the cells exposed to UVB radiation compared to those exposed to UVC radiation was observed. In conclusion, the mitotic index analysis showed no significant differences in cell activity between UVC and UVB irradiation compared with control samples. The results from this study support the use of Allium cepa and cytogenetic endpoints as a biodosimetric method for ultraviolet radiation.