Collagen and elastic fibres are generally present in organs whose normal function requires great resistance and elasticity. The aim of this study was to localize the collagen and elastic fibres in the stroma of the bovine lactating mammary gland and to determine their role in the process of milk ejection. For this purpose, the histochemical staining for collagen and the immunohistochemical method for the detection of elastin were used. The accumulation of scattered collagen fibres was observed between and inside the lobules where they formed distinct septa. Between secretory alveoli, the collagen fibres were found to be concentrated into two incomplete layers surrounding the blood capillaries. Bundles of elastic fibres in high density were located in the interlobular spaces. A dense network of elastic fibres was located between adjacent alveoli. Elastic membranes were located beneath the secretory epithelium. The high concentration of the collagen and elastic fibres indicated, that both types of fibres play a significant role in the resistance during the secretory stage and in the recoil of the mammary gland after milk ejection.
Ductus deferens plays an important role in sperm transport and participates in the preservation of structure, maturation, and viability of sperm. In this study, we have immunohistochemically examined the ductus deferens in the goat. For immunohistochemical study the following monoclonal antibodies were used: cytokeratin 18, α-smooth muscle actin (α-SMA), vimentin and elastin. Morphologically, three distinct layers were identified in the goat ductus deferens — tunica mucosa, tunica muscularis and tunica adventitia. The epithelium of the mucosa was intensely stained with cytokeratin 18 (CK 18). The fibroblasts in the lamina propria and blood capillaries in the muscle layer showed positive reaction for vimentin. A positive reaction for α-SMA was observed in the smooth muscle cells of the tunica muscularis in the internal, middle and outer sublayers. An intense positive reaction for α-SMA was observed in the wall of the blood vessels. Elastic fibers in the form of a loose meshwork were present in all three layers. The high density of elastic fibers were found in the tunica adventitia.
The bovine mammary gland is a special gland characterized by high secretory activity. During lactation the cellular and fibrous components of the interstitial tissue septa are exposed to store accumulated secretory products. The aim of this study was to find and study the cells in the stroma of the bovine lactating mammary gland. For this purpose, the immunohistochemical methods and antibodies against the smooth muscle actin, vimentin, and desmin were used. The myoepithelial cells (MEC) which stained with smooth muscle actin (SMA), were found supporting the secretory units and the intralobular ducts. Coexpression of the SMA and desmin were found in the smooth muscle cells of the blood vessels. The fibroblasts (myofibroblasts) and free cells positive to vimentin were located in the connective tissue septa. The results of this study on the mammary glands indicated that smooth muscle cells (SMC) were altered in the lactating mammary gland, with additional cells such as fibroblasts (myofibroblasts) participated in the storage and after milk let-down they allowed the mammary glands to return to their original state.