PLATFORM SESSION 19. PITUITARY HORMONES AND GROWTH FACTORS
Tuesday, August 3, 2004
4:30 PM–6:30 PM
Chair: Christine Quirk
Co-Chair: James Dias
(586) TRANSFORMING GROWTH FACTOR INHIBITS PROLIFERATION OF SOMATIC CELLS WITHOUT INFLUENCING GERM CELLS IN THE CHICK EMBRYO OVARY.
Pedernera, Enrique 1, Alcántara, Luz1, Garciadiego, David1, Rodríguez-Mata, Verónica2, Méndez, Carmen, 1 Department of Embryology, México DF, Mexico2 Department of Cell and Tissue Biology, México DF, Mexico
ABSTRACT- This study aimed to evaluate TGF induced changes in the proliferation index of somatic and germ cells in the chick embryo ovary. The left ovary of 9-day-old chick embryo was organ cultured on polycarbonate membranes in a defined medium. TGF1 and TGF2 were added to the culture medium. A dose-response curve and a time-elapsed study of TGF effect were evaluated by measuring the total number of somatic and germ cells in the cultured gonad. The number of somatic cells in the ovary increased during the culture. This increment was not observed in the presence of TGF (10 ng/ml), the number of somatic cells remained almost constant during the culture. The growth reduction in the TGF-treated ovary was detected after 48 h of culture, being 50% of the control at 72h of culture. The total number of germ cells in the TGF-treated ovary augmented during the culture in a similar way to controls. Soluble betaglycan was used to antagonize the effect of TGF; the effect TGF1 and TGF2 on somatic cell number was reverted by betaglycan in the cultured ovary. The proliferation index and the percentage of apoptotic cells were measured by bromodeoxyuridine (BrdU) incorporation and by TUNEL technique, respectively. BrdU incorporation in somatic cells was significantly reduced in TGF-treated ovary at 24 h and 72 h of culture, while the number of apoptotic cells was not significantly increased. Histological study of the cultured ovary showed a migration of germ cells from the cortical to the medullar region in the TGF-treated ovary. The disorganization of the ovarian cortex and the germ cell migration were relevant changes observed after TGF treatment. TGF impaired somatic cell proliferation in the chick embryo ovary, without increasing apoptosis. Germ cell proliferation remained unchanged but germ cells were induced to migrate from the ovarian cortex. Supported by DGAPA-UNAM (IN 214403).
KEY WORDS: chick embryo ovary, cell proliferation, TGF, germ cells