EFFECT OF STEROID HORMONES ON IN VITRO GROWTH OF OOCYTE From Early Antral Follicle In Pig

Abstract

Many approaches have been investigated to set up the optimum condition for growing oocytes in vitro in porcine. The main aim of the present study was to examine the effect of the combination of Estradiol (E) and Androstenediol (A) and addition of collagen in maintaining connections between oocytes and surrounding granulosa cells on the in vitro development of small oocytes collected from early antral follicle (1-<2 mm). The reason for this experiment is that in vitro growth culture of oocytes in Viet Nam is still not developed yet that could not supply the potential source of oocytes for stem cell technology and in vitro fertilization, we want to increase the number of oocytes go to fully-growth stage for many applications. So that we do this experiment in which growing oocytes were cultured for 5 and 7 days in 3 different culture mediums. Medium 1 (M1); Medium 2 (M2) and Medium 3 (M3). During in vitro growth culture, OGC structures were maintained in the medium with steroid hormones. The mean diameter of oocytes grown in the M2 with both Estradiol and Androstenediol and in M3 was increased from (91.54± 1.16 μm) at Filamentous Chromatin stage to around (118.20 ± 1.81 μm) at GV stage. The size of fully- growth oocytes is similar to oocytes collected from 4- to 6-mm antral follicles (122.1±2.2μm). In subsequent in vitro maturation culture of M1 ( 5 and 7 days ), (28 % and (28.4 %) of oocytes grown to fully growth , respectively, meanwhile, oocytes in the M2 go to GV stage at a higher rate (26.7 %) and ( 33.3%) respectively. Moreover, oocytes culture in M3 have the highest rate of oocytes go to GV stage (43.3%) and (36,4 %) respectively. The result demonstrate that oocytes cultured in M3 for 5 days give the highest percentage of GV stage and maintain the surrounding cumulus of fully growth oocytes. This result will support for in vitro growth culture system to obtain the high quality of oocytes for producing good embryo after in vitro maturation and fertilization. Key words: Steroid hormones, early antral follicle, in vitro growth (IVG), growing oocytes,