Characterization of Collagens Fibers (I, III, IV) and Elastin in the Extracellular Matrix of Normal and Neoplastic Canine Prostate

Collagen (Coll) is the most common protein in the extracellular matrix, responsible for providing tissue structure and support. In some types of cancer, including prostate cancer (PC) abundant collagen was identified and related to tumor progression and metastasis. This study aimed to investigate Coll-I, III, IV and elastin in normal canine prostatic tissue and PC, using the Picrosirius red (PSR) and Immunohistochemical (IHC) analysis. Eight normal prostates and 10 PC from formalin-fixed, paraffin-embedded samples were used. Collagen fibers area was analyzed with ImageJ software. The distribution of Coll-I and Col-III was approximately 80% around prostatic ducts and acini, 15% among smooth muscle and 5% around in blood vessels, in both normal prostate and PC. Immunostaining for type IV collagen was observed in the basal membrane of prostate acini, smooth muscle, blood vessels, and never fibers of normal and PC samples. Elastic fibers were found in the septa dividing the lobules and around the prostatic acini of normal samples. A high amount of elastic fibers was observed around the ducts and the urethra in normal and canine PC. The distribution and area percentage of staining for collagen are similar in normal and neoplastic canine prostate when analyzed with PSR and IHC.