HISTOLOGICAL ANALISIS OF THE OVARY OF Physalaemus biligonigerus AND Pleurodema borellii

MANZANO CAROLINA; PUCCI ALCAIDE ANA; ZELARAYÁN LILIANA ISABEL

Congreso; XXXIII JORNADAS CIENTÍFICAS ASOCIACION DE BIOLOGIA DE TUCUMAN; 2016

In anuran amphibians, during the reproductive period, sexually mature females present a well developed gonad with follicles in different stages of growth. We analyzed for the first time the structural features of the ovarian follicles of two species of anura: Physalaemus biligonigerus and Pleurodema borellii. The ovaries of the two species were fixed in buffered formalin at pH 7 and included in Histowax. 4 µm cuts were stained with hematoxylin-eosin (HE) and Toluidine Blue (TB) at pH 7. In the parenchyma of the ovarian cortex of both species we observed follicles in different stages of growth: previtellogenic, vitellogenic and postvitellogenic. No oogonia were observed in the analyzed cuts. In the ovarian follicles the following structures were observed: the theca, a layer of flat follicular cells and the vitelline envelope surrounding the oocytes. Follicles in different stages of growth were immersed in a connective tissue matrix (including fibroblasts, collagen fibers and blood vessels) and showed variations in size and structure (position and size of the germinal vesicle, vitelline platelet accumulation and appearance of pigment in the animal pole). In the postvitellogenic oocytes we observed migration of the germinal vesicle to the animal pole with retraction of the nuclear envelope. The predominance of vitellogenic and postvitellogenic follicles indicates that the ovaries of these females were in a period of immediate ovulation.