• Animal cells and systems
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• v.4 no.4
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• pp.347-352
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• 2000

Programmed cell death, apoptosis, is a mechanism to maintain tissue homeostasis. Although the apoptotic process in rodent mammary tissues has been known to occur at the onset of involution, little is known about programmed cell death in the bovine tissues. Therefore, the purpose of this study was to investigate the molecular and cellular basis of apoptotic process in bovine mammary cells. Mammary tissues were obtained at different lactational and involurional stages. By apoptosis in situ endlabeling assay, apoptotic cells were found around the acinar celt lining in regressing bovine mammary tissues. The apoptosis-related genes bel-2 and bax were detected throughout involution by Northern blotting assay. The level of bax mRNA was dominantly expressed during involution. On the other hand, the bel-2 RNA transcripts were constantly expressed by 14 of post-lactation and declined thereafter. The expression of the testosterone-repressed prostate message-2 (TRPM-2) RNA transcripts, a marker for tissue remodeling, was increased as involution progressed. TNF a, were induced the DNA fragmentation and enhanced the expression of bax mRNA. In addition, milk protein secretion and amino acid uptake were decreased in mammary acinar culture treated with TNF $\alpha$. These results indicate that bovine mammary cells undergo apoptotic process after the cessation of milking and that TNF $\alpha$ may trigger apoptosis in lactating bovine mammary acini.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.551-558
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• 2017

To study and validate tissue-specific promoters and vectors, it is important to develop cell culture systems that retain the tissue and species specificity. Such systems are attractive alternatives to transgenic animal models. This study established a line of porcine mammary gland epithelial cells (PMECs) from a primary culture based on the cellular morphology and mRNA levels of porcine beta-casein (CSN2). The selected PMECs were stained with the cytokeratin antibody, and were shown to express milk protein genes (CSN2, lactoferrin, and whey acidic protein). In addition, to confirm the acini structure of PMEC932-7 in 3D culture, live cells were stained with SYTO-13 dye, which binds to nucleic acid. The acini of these PMECs on matrigel were formed by the aggregation of peripheral cells and featured a hollow lumens. The system was demonstrated by testing the effects of the culture conditions to cell culture including cell density and matrigel methods of the PMECs. These results suggest that PMECs possess the genetic and structural features of mammary epithelial cells.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.274-278
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• 2002

A culture system for lactating rat mammary acini was evaluated, where the primary indicator of performance was lactose secretion, measured by a sensitive bioluminescence assay. Lactose secretion was reduced by half (p<0.01) over the first 6 h of culture by overnight feed withdrawal (FW) from tissue donors but was sensitive to increased glucose concentration in the culture media (p<0.001) up to 30 mM. Lactose production of cells from fed donors over the first 6 h in culture in 30 mM glucose was 8.9 fmol/cell/h - a rate calculated to be about half that in vivo. No significant difference was shown in lactose secretion by cells from fed or FW rats over 6-24 h. Lactose secretion was 3.6 fmol/cell/h by cells from fed animals in 40 mM glucose concentration media over the 6-24 h culture period. Addition of insulin to the culture media had no effect on rates of lactose secretion while addition of prolactin and hydrocortisone, with or without insulin, significantly (p<0.001) decreased lactose production over both 0-6 h and 6-24 h culture periods. Lactose synthesis in vitro was significantly enhanced by aeration of the media during collagenase digestion of mammary tissue (p<0.05). No improvement in lactose secretion was effected by shaking of cells during culture, Matrigel coating of culture dishes or change in cell density over a range up to 2.5 million cells per ml.