Relationship between histology, development and tumorigenesis of mammary gland in female rat

Abstract

The mammary gland is a dynamic organ that undergoes structural and functional changes associated with growth, reproduction, and post-menopausal regression. The postnatal transformations of the epithelium and stromal cells of the mammary gland may contribute to its susceptibility to carcinogenesis. The increased cancer incidence in mammary glands of humans and similarly of rodents in association with their development is believed to be partly explained by proliferative activity together with lesser degree of differentiation, but it is not completely understood how the virgin gland retains its higher susceptibility to carcinogenesis. During its developmental cycle, the mammary gland displays many of the properties associated with breast cancer. An early first full-term pregnancy may have a protective effect. Rodent models are useful for investigating potential breast carcinogens. The purpose of this review is to help recognizing histological appearance of the epithelium and the stroma of the normal mammary gland in rats, and throughout its development in relation to tumorigenic potential.

Histological and immunohistochemical characterization of the Mongolian gerbil’s mammary gland during gestation, lactation and involution

“…Once the alveoli were developed and the epithelium differentiated as secretory cells, the epithelial height, and consequently, the cell volume increased with gestation. The results that were observed during the analyses of the epithelial height measurements and the acini diameters led one to conclude that a higher epithelial height was observed during pregnancy, the same as in rats (Líška et al, 2016). A deposition of fat droplets and secretion vesicles in the cytoplasm of the secretory cells was responsible for the increase in its volume.…”

“…To this aim, the unilocular fat cells showed a reduction in their size, since they provided energy and substrates for the synthesis of the growth factors and the hormones necessary for the differentiation and lactation, apart from yielding space for the development of the ducts and the acini (Hovey and Aimo, 2010). As in several rat strains (Líška et al, 2016), the gerbil's mammary gland had a higher amount of fat in their non-secretory portions.…”

“…In rats, the parenchymal compartment of the mammary gland is composed of different epithelial structures with distinct morphological and functional activities, comprising the luminal epithelium of ducts, ductules, terminal end buds, alveolar buds, alveoli and the underlying myoepithelial layer (Líška et al, 2016;Masso-Welch et al, 2000). As in most glandular tissues, the adult mammary gland comprises multiple cell types, including epithelial, adipose, fibroblasts, immune, lymphatic and vascular cells that work together to sculpt and maintain a functional organ.…”

Regeneration of Bovine Mammary Gland in Immunodeficient Mice by Transplantation of Bovine Mammary Epithelial Cells Mixed with Matrigel

“…The female mammary gland is a dynamic organ that undergoes structural and functional changes in relation to growth, such as before and after puberty, and to reproduction events such as pregnancy and weaning (17). The process of initiation and branching morphogenesis of mammalian gland is mutually regulated by hormone (GH), estrogen, and insulin-like growth factor (IGF)-1 to generate a ductal tree (18).…”

In Vivo Dielectric Properties of Healthy and Benign Rat Mammary Tissues from 500 MHz to 18 GHz

“…Rat mammary gland development and mammary carcinoma formation is similar to human mammary tissue alterations [23]; therefore, rats are frequently used as experiment animals for many different studies including but not limited to drug and toxicology research [24][25][26]. Despite these similarities, the size of the healthy human breast tissues differs from rat breast tissues due to the heterogeneous presence of adipose, glandular and fibroconnective tissues in large volumes when compared to rat breast tissues.…”