Regression of mouse mammary gland anlagen in recombinants of Tfm and wild-type tissues: testosterone acts via the mesenchyme

The incidence of mastitis is high during the postpartum stage, which causes severe pain and hinders breast feeding in humans and reduces milk production in dairy cows. Studies suggested that inflammation in multiple organs is associated with oxidative stress and nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element pathway is one of the most important antioxidant pathways, but the effects of Nrf2 on antioxidation in the mammary gland during mastitis are still unclear. In this study, intramammary lipopolysaccharide (LPS) challenge was carried out in wild-type (WT) and Nrf2 knockout mice. Results showed that the expression of Nrf2 affected the expression of milk protein genes (Csn2 and Csn3). Importantly, LPS treatment increased the expression of Nrf2 and HO-1 and the content of glutathione in the mammary gland of WT mice, but not in Nrf2(-/-) mice. The expression levels of glutathione synthesis genes (GCLC, GCLM, and xCT) were lower in Nrf2(-/-) mice than in WT mice. Moreover, mitochondrial-dependent apoptotic and endoplasmic reticulum stress were significantly relieved in WT mice compared with that in Nrf2(-/-) mice. In summary, the expression of Nrf2 may play an important role in prevention of oxidative and organelle stresses during endotoxin-induced mastitis in mouse mammary gland.

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Prolactin inhibits cell loss and decreases matrix metalloproteinase expression in the involuting mouse mammary gland but fails to prevent cell loss in the mammary glands of mice expressing IGFBP-5 as a mammary transgene

Journal of Molecular Endocrinology ◽

10.1677/jme.1.01873 ◽

2006 ◽

Vol 36 (3) ◽

pp. 435-448 ◽

Cited By ~ 20

Author(s):

D J Flint ◽

M Boutinaud ◽

C B A Whitelaw ◽

G J Allan ◽

A F Kolb

Keyword(s):

Mammary Gland ◽

Transgenic Mice ◽

Mammary Epithelium ◽

Transgenic Animals ◽

Cell Loss ◽

Mouse Mammary Gland ◽

Luciferase Reporter ◽

Wild Type ◽

Luciferase Reporter Gene ◽

Gland Weight

Insulin-like growth factor-binding protein 5 (IGFBP-5) mediates involution of the mammary gland. The decrease in DNA content and mammary gland weight which accompanies involution was inhibited by prolactin (PRL) in wild-type but not transgenic mice expressing IGFBP-5. Phospho-STAT5 protein levels were significantly lower in IGFBP-5 transgenic mice during lactation suggesting that IGFBP-5 antagonises PRL signalling in the mammary epithelium. In contrast, phospho-STAT3 levels increased during involution to a similar extent in both wild-type and transgenic mice and were unaffected by PRL. PRL inhibited gene expression of matrix metalloproteinases (MMPs) 3 and 12 but not tissue plasminogen activator or plasmin in wild-type and transgenic animals. The effects of PRL on MMPs appear to be indirect since PRL failed to inhibit MMP-3, -7 or -12 expression in HC-11 cells or in a co-transfection including an activated PRL receptor, STAT5 and a MMP-3-luciferase reporter gene. PRL is a potent inhibitor, both of cell death, an effect which is suppressed by IGFBP-5, and of MMP expression, which is independent of the actions of IGFBP-5.

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Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081097 ◽

1978 ◽

Vol 36 (2) ◽

pp. 46-47

Author(s):

Jan Zarzycki ◽

Joseph Szroeder

Keyword(s):

Mammary Gland ◽

Protein Denaturation ◽

Chemical Constituents ◽

Freeze Substitution ◽

Electron Microscopic Examination ◽

Mouse Mammary Gland ◽

Electron Microscopic ◽

Preparation Methods ◽

Microscopic Studies ◽

Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

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