ISSN:
1573-675X
Keywords:
Apoptosis
;
Fas
;
mammary gland after weaning
;
mouse
;
TNF-α
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Mammary gland involution after cessation of milk production is associated with extensive loss of secretory epithelial cells. In order to study the mechanism of mammary gland involution, litters were removed on day 20 of lactation and morphological and biochemical changes were examined in GR/A mice andlpr cg mice lacking functional Fas. DNA fragmentation occurred 24 h after weaning both in GR/A mice andlpr cg mice indicating that apoptotic cell death occurs during involution of mammary glands.In situ 3′-end labelling method revealed apoptotic cells in epithelial cells lining alveolar lumens and in cells shed into the alveolar lumen. The number of apoptotic cells plateaued on day 2 of weaning in mammary glands of GR/A mice. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that expression of bcl-2, Fas ligand, keratinocyte growth factor (KGF) and transforming growth factor-β1 (TGF-β1) increased on day 1 of weaning in the process of involution of mammary glands in GR/A mice. In mammary glands oflpr cg mice, RT-PCR showed that expression of bcl-2, Fas ligand, KGF, tumour necrosis factor-α(TNF-α) and TGF-βs increased in the process of involution. These results suggest that the Fas ligand, TGF-β1 and TNF-α are involved in the involution of mammary glands after weaning. TNF-α and anti-Fas antibody directly killed more than 80% of mammary cells from p53 knockout micein vitro within 24 h in the presence of actinomycin D, supporting the hypothesis that Fas and/or TNF-α are involved in the induction of apoptosis of mouse mammary glands.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01321103
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