SEASONAL VARIATIONS OF IMMUNOHISTOCHEMICAL EXPRESSION OF S-100 PROTEIN IN INTERSTITIAL CELLS OF VISCACHA PINEAL GLAND

BUSOLINI FABRICIO; GALLOL EZEQUIEL; ROSALES GABRIELA; FILIPPA VERÓNICA; MOHAMED FABIAN

San Miguel de Tucumán

Congreso; Tercera Reunión Conjunta de Sociedades de Biología de la República Argentina; 2015

Sociedad de Biología de Argentina

The presence of S-100 protein, a glial marker, was reported in the pineal gland of numerous mammals. Viscacha is a native rodentwhich exhibits seasonal adaptations and a reproductive cycle synchronized by the environmental photoperiod. The aim of this workwas to study the seasonal expression of S-100 protein in the pineal gland of adult male viscachas by immunohistochemistry. Theglands (n=4 for season) were processed for light microscopy, the polyclonal anti S-100 was used and positive (rat cerebellum) andnegative (omission of primary antibody) controls were performed. The percentage of immunopositive area (% IA) was quantified by a computer- image assisted analysis system. The interstitial cells were irregular, oval or stellate-like in shape, with long cytoplasmicprocesses that form networks extending towards pinealocytes or blood vessels. Immunostaining for the S-100 protein was bothnuclearand cytoplasmic, only nuclear or only cytoplasmic and exclusive for the interstitial cells. The values of % IA in the autumn were 2.40± 0.53, in the winter 3.40 ± 0.49, in the spring 2.32 ± 0.76 and in the summer 1.47 ± 0.03. In the winter, % IA was significantly higherthan in the summer (p