Apoptosis and expression of related proteins in mammary gland of heifers during early lactation

摘要

Lactation is biologically significant and economically important and it has particular nutritional implications in the case of dairy cows. Programmed cell death is a physiological event during mammary gland involution and also plays an important role in the regulation of milk production and persistence of lactation (Capuco and Akers, 1999), although it is numerically less relevant (4.8% vs 2.4%; Wilde, personal communication; Quarrie et al., 1995). Proteins belonging to the bcl-2 family, namely bax and bcl-2, are involved in the regulation of cell apoptosis (Reed, 1997) which also occurs in the mammary glands of lactating mice (Heermeier et al., 1996) and sheep (Colitti et al., 1999); bax acts as a pro-apoptotic and bcl-2 as an anti-apoptotic agent. The aim of the current research was to investigate the morphological organization and the extent of cell apoptosis and proliferation of mammary cells in heifers during early lactation. The possible relationship between mRNA expression of bax and bcl-2 and cell fate was also studied.