Effect of low level, short wavelength ultraviolet radiation on sperm chromatin

摘要

Objective:To evaluate the effects of low level ultraviolet (UV) radiation on sperm chromatin structure.Methods:The target study was divided into three groups: (i) males with proven fertility (n=40 ) was taken as GroupⅠ (control);(ii) Oligoasthenozoospermic (OAT) cases as GroupⅡ (n=36);(iii) males with unexplained infertility (MUI) cases (n=42) as GroupⅢ. Specific techniques were used to study the impact of UV radiation (Pre and Post UV exposure) on the sperm nuclear DNA viz. Aniline blue staining was for detection of immature chromatin. Chromomycin A3 fluorescence staining was used to determine protamine-DNA dissociation by intense fluorescence of protamine deficient sperm cells and neutral comet assay was for evaluation of DNA fragmentation. Statistical analysis was carried out using Student''st-test (GraphPad Prism Version-6). Level of significance was considered atP<0.05.Results: The data revealed that spermatozoa of OAT and MUI cases when exposed to UV-radiation showed higher percentage of immature sperm compared with normal fertile individuals. Higher percentage of Chromomycin A3 fluorescence in OAT and MUI cases revealed impaired DNA-protamine binding with subsequent DNA fragmentation after exposure to UV.Conclusions:In the present study, sperm chromatin is at higher risk of DNA fragmentation in the infertile (OAT and MUI) cases due to UV irradiation (254 nm). Hence, short duration UV exposure is detrimental to sperm DNA which could affect ensuing generations.