Title: First demonstration of decorin, an extracellular matrix molecule, in bovine mammary tissue Authors
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: March 6, 2012
Publication Date: N/A
Technical Abstract: In the mammary gland, the extracellular matrix (ECM) is secreted by and surrounds cells located in both mammary parenchyma (PAR) and stroma. Decorin is an ECM proteoglycan with cell growth regulatory effects mediated by its ability to interact with growth factors or up-regulation of cyclin-dependent kinases. It also serves a structural role by regulation of collagen crosslinking. Based on these known roles, we undertook a pilot scale study to examine the spatial and temporal localization of decorin in bovine mammary tissue at various physiological stages. Mammary PAR (n=6) was obtained from female Holsteins (n=4). Samples represented three prepubertal times (d40, 56 and 100 of postnatal life), two gestational times (d213 and 248 of gestation) and one lactating time point (d10 post calving). Slides were subjected to immunohistochemical staining for the decorin antigen. A horseradish peroxidase conjugated secondary antibody and diaminobenzidine chromagen were used for detection. The negative control for the assay was incubated with control sera instead of the decorin primary antibody; all other procedures were the same. The negative control was free of chromagen. Our analyses demonstrated that decorin is present in the ECM of mammary PAR, which includes epithelial cells, intralobular stroma and interlobular stroma. Furthermore, temporal and spatial localization changed with physiological stage. At all time points observed, expect for d56, decorin was not observed immediately surrounding epithelial cells comprising ducts. Across all time points, decorin localization in the intralobular stroma was minimal. Interlobular stroma showed a temporal distribution pattern of decorin staining. At d40, the gestational time points and d10 post calving, decorin localization was high; at the d56 and d100 prepubertal time points, comparatively less deocrin localization was noted in the interlobular stroma. This is the first demonstration of the localization of decorin in bovine mammary PAR. This work suggests that decorin may be important in the regulation of growth, development and remodeling of the bovine mammary gland.