Age-related changes in genomic stability of horses

► The changes of the NDI value was insignificant during aging. ► Apoptotic cell level was increased during aging. ► Old horse lymphocytes were more prone to oxidative DNA damage, sister chromatid exchange and bleomycin-induced chromatid breaks. ► Micronuclei formation was dropped during aging which was strongly correlated with elevated occurrence of apoptosis within old groups. ► Age-associated changes in genomic stability may contribute to progress of aging process in the horse.