Study Of Mammary Gland Growth And Mammary Stem Cells Of The Embryonic And Early Born SD Rat

Mammary gland of mammal is a very special organ. The mammary gland can be regenerate and degenerative in repeated pregnancy and birth. It is the only repeated regenerate organ in born animals. As early as 1959, a study from DeOme and so on confirmed that mammary gland can be regenerate when the mammary gland tissue transplanted to the mammary fat pad of the rats which mammary gland were excised. In 1967, a series studies from Horishino and so on indicated that the mammary gland epithelial cell had the ability self-duplication, and the transplantation can be maintained for 7 times. In 1998, Kordon and so on studied the mammary gland of rodent and found that there is at lest one kind of multifunctional stem/ancestral cell in mammary gland. Because of the relationship between regenerate mammary gland and mammary gland tumor, and the particularity of self-growth of mammary gland, it is the appropriate model to study the mechanism of generation of organ, differentiation of cell and regeneration of organ. In 1999, Chepko and Smith confirmed the existence of mammary stem cell lineage. These mammary stem cells ensure the regeneration, galactopoiesis and degeneration of mammary gland in repeated pregnancy and birth. Different growth period has different proportional stem cells in mammary gland. They maintain and ensure the character of mammary gland growth.