Transplantation results from implantation of mammary tissue fragments of, aged-nulliparous and aged-multiparous mammary epithelial cells into mammary fat pads of 3-wk old female mice.

<p>Hosts were maintained as virgins for 8 weeks after the transplant. At the end of the 8 weeks, mammary glands were collected for morphology analysis and fragments were collected for the serial transplantation. All fragments contributed to complete outgrowth of the mammary gland when implanted into cleared mammary fat pad. (<b>A</b>) Portrays a representative whole-mount image of the fifth generation transplant (panel a) of an outgrowth of aged-nulliparous mammary tissue fragment into the cleared mammary fat pad (CFP), (panel b) shows the comparable outgrowth of aged-multiparous mammary tissue fragment into the CFP. (<b>B</b>) Serial transplantation results from transplant of paired aged-nulliparous and aged-multiparous mammary donor fragments into cleared mammary fat pads. Tissue fragments were collected from 20-month old mice (20-Mo-Donor), 22 month old mice (22-Mo-Donor) or 23-month old mice (23-Mo-Donor) as donors for the first transplant generation. Each donor mouse represented an independent experiment. In all cases fragments from the matched donors produced comparable mammary outgrowths.