Regularity of ultraviolet (UV)-induced NIH3T3 cell damage and characteristics of DNA cleavage in UV-induced NIH3T3 cells apoptosis

To study the regularity of Ultraviolet (UV)-induced NIH3T3 cell damage and characteristics of DNA cleavage in UV-induced NIH3T3 cells apoptosis. Methods: Regularity of ultraviolet (UV)induced NIH3T3 cell damage was studied by two ways: The cells were irradiated for different time lengths and cultured for the same time (24 h) length and irradiated for same time length (10 min), cultured for different time length. The characteristics of DNA cleavage in NIH3T3 cells apoptosis induced by UVB were also studied. Results: It was found that ultraviolet A (UVA), ultraviolet B (UVB), ultraviolet C (UVC) have their particular regular patterns of cell damage respectively. Conclusion: DNA cleavage of apoptotic cells does not always initiate at inter-nucleosomes. Inter-nucleosomal DNA cleavage should not be the sole criterion for identifying apoptosis.