Abstract

Apoptosis was examined by in situ end labelling (ISEL) of DNA in ewe and cow mammary sections representing the cycle of mammary development, lactation and regression. Labelled nuclei, identifying apoptotic dying cells, were found in tissues from all developmental stages. Generally, apoptosis was low in tissue from virgin animals, moderate in 3 and low in 2 week udders from prepartum ewes and mid pregnant cows, moderate to high in udders from 1 week post partum ewe udders, moderate to low in lactating ewes and cows and slightly higher in involuting ewe and cow udders. Apoptosis was also generally higher in alveoli in stasis than in lactating alveoli. A dramatic finding was that there was intense labelling with both 35S and DIG in the lumenal contents of some alveoli in stasis/involution particularly with animals in later lactation. This suggested that there was a significant amount of ragged DNA ends in the lumen of these alveoli.

AJ, Molenaar, RJ Wilkins, and SR Davis

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 71-76, 1996