2 research outputs found
Effect of Epidermal Growth Factor on in-vitro culture of feline preantral follicles
No full textIn vitro culture of preantral follicles would result in follicular development and production of a high number of competent
oocytes that can be destined to assisted reproduction programs. However, in vitro systems supporting complete follicular growth from early primordial stages have only been achieved in mice (I). The improvement of culture system is aimed at defining cultural conditions similar to the in vivo environment. Growth factors may act as autocrine or paracrine regulators to locally modulate follicular development. It has been shown that Epidermal Growth Factor (EGF) is a vigorous mitogen of follicular cells and induces follicular development (2). The aim of this study was to investigate
the effect of EGF on the in vitro development of preantral follicles recovered from domestic cat ovaries. Secondary follicles surrounded by complete basal membrane and containing more than one layer of granulosa cells were selected as previously described (3) and cultured for 6 days at 37°C and 5% C02 in air in Minirnum Essential Medium (Sigma Chemical Co., USA) with EGF 100 ng/ml or without (Control).
In vitro development was assessed by measuring the diameter of follicles and oocytes before and after culture. A significant increase in the size of follicles was observed when EGF was supplemented to the culture medium (increase
of 15.8%±2.53% vs 7.6%±5.2%; P<0.05), whether
oocyte diameter was not affected by cultural conditions. Viability of follicles was assessed at D6 by trypan blue staining and the results showed that follicle viability was also enhanced by EGF (75% vs 50%; P<O.05). In conclusion, feline preantral follicles respond to culture conditions and
these results prompt to extend the culture time in order to achieve the antrum formation. References 1) Demeestere et
al., Hum Reprod. 2002; 17:2152-9. 2) Morbeck et al., J Reprod Fertil. 1993;99:577-84.3) Lima et al., Rev Bras Reprod Anim 2003;27:396-7
In vivo embryo development in bitches inseminated laparoscopically after ovulation time estimated based on a single progesterone determination
No full textLogistic and economical limitations are often the causes of dog owners not accurately monitoring the estrous cycle and the optimal insemination time. The aim of this study was to evaluate in vivo early embryonic development in bitches, after the analysis of sequential vaginal cytologies associated to single progesterone measurement and single laparoscopic insemination with high quality semen (fresh and with high spermatozoa concentration) or low-quality semen (frozen/thawed and with low spermatozoa concentration) at 48 h post- ovulation time predicted on a single progesterone measurement. Ten bitches were inseminated with 250 x 106 fresh spermatozoa (80% motility), and ten with 80 x 106 frozen/thawed spermatozoa (60% motility) in the cranial part of each uterine horn. Seven days later, ovariohysterectomy
was performed and the oviducts and uterine horns and body were flushed to recover embryos and unfertilized oocytes. In 80% of the bitches inseminated with fresh and 50% of bitches inseminated with frozen/thawed semen, embryos at 2 to 8 cells stage were recovered mostly from the, oviducts. This study indicates that pregnancies can be obtained with a single laparoscopic intrauterine insemination after single serum progesterone measurement, although with a low number of embryos. This result should be taken into account in case economic or logistic restrictions that affect the possibility of owners to plan an accurate monitoring of the optimal breeding time using fresh and frozen semen
