GFAP EXPRESSION IN PINEAL GLAND OF VIZCACHA DURING LONG AND SHORT PHOTOPERIODS

BUSOLINI FABRICIO; ROSALES GABRIELA; FILIPPA VERÓNICA; MOHAMED FABIAN

La Falda, Cordoba.

Congreso; XIX Jornadas Científicas. Sociedad de Biología de Córdoba.; 2013

Sociedad de Biología de Córdoba

The viscacha is a seasonal breeding rodent photoperiod dependent. The pineal gland of this rodent shows marked changes in the ultrastructural morphology of pinealocytes according to the length of the days. The aim of this work was to study the expression of glial fibrillary acidic protein (GFAP) in pineal gland of adult male viscacha during long (LP, summer, n = 4) and short (SP, winter, n = 4) photoperiods. This protein is part of intermediate filaments and is used as a marker of astrocytic and glial cells. Anti-GFAP and the biotin-streptavidin system (DAB chromogen) were used. The percentage of immunopositive area (% AI) was measured by image analysis. GFAP localization was only observed in the pineal interstitial cells mainly in cytoplasmic projections. The morphometric analysis revealed significant differences between LP (% AI = 5.21 ± 0.99) and SP (% AI = 20.33 ± 4.53), p < 0.001. These results demonstrate variations in the expression of GFAP in interstitial cells, with maximum values in winter (LP), according to changes previously reported in pinealocytes and in the melatonin synthesis. Therefore we suggest that the interstitial cells of the pineal gland of viscacha, in addition to being supporting and nutritional elements as was described in other species, these cells are actively involved in glandular function.