ORIENTADOR: earaujo@vet.ufg.br

KEY-WORDS: CYR 61, dog, immunohistochemistry, prostate.

The prostate is the site of several diseases of the male reproduction tract in dogs above five years old, as well as in men.. Benign prostate hyperplasia (BPH) and neoplasia are the most frequent diseases and both are characterized by the increase of the organ size through cellular proliferation [2]. Therefore, it is recommended that dogs must be regularly examined by transrectal digital examination for prevention [7]. Histologically, the proliferation of this organ can be studied by using cellular proliferation markers like CYR61, a heparin-binding protein, cystein-rich from the angiogenic and vasculargenic regulators family called CCN and encoded by a gene induced by growth factors that associate to the extracellular matrix and cellular surface [4, 5]. This marker has high expression in blood vessel development, endothelial cell migration, wound healing, progressive tumors and condhrocyte differentiation [1, 6]. Thus, this study aimed to determine the presence of the angiogenic factor CYR 61 in canine prostates with proliferative alterations.

Paraffin embebed prostates from 12 dogs, previously classified in relation to histopathological changes, were subjected to immunohistochemistry. From the analyzed fragments, five (41.66%) were classified as displasia, five (41.66%) as BPH and two (16.66%) as prostatitis. Three m m thick tissue sections were attached to glass slides treated with organosylane (3-aminopropyl-triethoxisilane). After that, the sections were deparaffinized in xylene and antigens retrieved using pH 6.0 citrate buffered solution in microwave. Endogenous peroxidase neutralization was performed by using a mixture of 60% of methanol and 40% of hydrogen peroxide for 15 minutes, followed by blockage with 3% bovine seric albumin for 2 hours. Anti-CYR61 antibody (H-78, Santa Cruz Biotechnology - USA) was incubed in 1/400 dilution at 4ºC in a humid chamber overnight. The secondary rabbit biotinylated anti-IgG antibody (Vector Laboratories) was added. The reaction was detected by addition of diaminobenzidine-peroxidase (DAB). The sections were counterstained with Harris’ hematoxilin and observed in an optical microscope.

In dysplasia cases, intense staining of CYR61 in the stroma was observed, clearly showing its vascularization, confirming results obtained before [1, 6]. In contrast to dysplasia, CYR-61 staining was more intense in alveolar epithelium in BPH fragments, suggesting accentuated proliferation [4, 5]. CYR61 was recently found in human prostates with BPH and it is believed that such finding in these prostates has great application to diagnosis and probably to therapeutic purposes [8]. Therefore, this first description of CYR 61 expression in analogous cases in dogs suggests similar pattern for this species, also pointing to therapeutic potential. In prostatitis cases, a CYR 61 staining pattern in the tissue could not be established.

Babic, A.M., Kireeva, M.L., Kolesnikova ,T.V., and Lau, L.F. CYR61, a product of a growth factor-inducible immediate early gene, promotes angiogenesis and tumor growth. Proc. Natl. Acad. Sci. 1998; 95: 6355-6360.

Chew, D. J. An overview of prostatic disease. Comp.Cont.Educ. Pract.Vet. 1997;19:80-85.

Manfred Kunz, Steffen Moeller, Dirk Koczan, Peter Lorenz, Roland H. Wenger,Michael O. Glocker, Hans-Juergen Thiesen, Gerd Gross, and Saleh M. Ibrahim. Mechanisms of hypoxic gene regulation of angiogenesis factor Cyr61 in melanoma cells. JBC Papers in Press. 2003; 278 (46):45651-45660.

Martinerie, C., Viegas-Pequignot, E., Nguyen, V.C., and Perbal, B. Chromosomal mapping and expression of the human cyr61 gene in tumour cells from the nervous system. Mol. Pathol. 1997; 50: 310-316.

O'Brien, T.P. and Lau, L.F. Expression of the growth factor-inducible immediate early gene cyr61 correlates with chondrogenesis during mouse embryonic development. Cell Growth Differ. 1992; 3: 645-654.

O'Brien, T.P., Yang, G.P., Sanders, L., and Lau, L.F. Expression of cyr61, a growth factor-inducible immediate-early gene. Mol. Cell Biol. 1990;10: 3569-3577.

Purswell, B. J. Prostatic diseases in dogs: a review. Veterinary Medicine. 2000; 95: 315-21.

Sakamoto S, Yokoyama M, Prakash K, Tsuruha J, Masamoto S, Getzenberg RH, Kakehi Y. Development of quantitative detection assays for CYR61 as a new marker for benign prostatic hyperplasia. J Biomol Screen. 2003; 8(6):701-11.

O projeto foi financiado pelo PROAP/UFG, CNPq, FUNAPE.