The in vitro culture supplements and selected aspects of canine oocytes maturation

Abstract

The maturation of oocytes is one of the most important steps determining their developmental competence. Due to the low percentage of oocytes of bitches that reach the MII stage, searching for reagents that may stimulate the growth and maturation of oocytes is still present in this species of mammals. The most important media supplements include gonadotropins (LH, FSH, hCG), growth factors (IGF, TGF, EGF, FGF), progesterone and follicular fluid. It is suggested that the supplement of EGF, and/or follicular cells may have an important influence on the percentage of cells that reach the MII stage. Despite plenty of research based on the improvement of bitch oocytes in vitro culture, the results obtained are still unsatisfactory. Moreover, in the long stages of canine oocytes maturation many molecular and morphological modifications (including changes in mitochondria structure and configuration in the cytoplasm) are involved.In this article, the influence of selected media supplements on the efficiency of bitch oocytes in vitro maturation was described. The molecular and morphological modifications during canine oocytes maturation were also considered in the text.

Nuclear competence and genetic expression of growth differentiation factor‐9 (GDF‐9) of canine oocytes in 3D culture

“…In comparison with the traditional 2D culture (microdrops of medium in Petri dishes or multiwell), the 3D systems sustain the survival and the growth of cultured cells, promoting the cytoplasmic and nuclear maturation of oocytes and the subsequent embryo development. As already mentioned, proper in vitro conditions for canine oocytes are not yet available, although many studies investigated different culture systems and the specific features of canine reproduction (Bukowska et al., ; Luvoni et al., ). In this species, the increasing plasma levels of progesterone before ovulation, the release of immature oocytes (GV stage) and the peculiar long‐term meiosis resumption in the oviduct markedly influence the in vitro outcomes of oocytes (Chastant‐Maillard et al., ; Songsasen & Wildt, ).…”

Early embryonic development, assisted reproductive technologies, and pluripotent stem cell biology in domestic mammals

“…Although conventional assisted reproductive technologies such as AI and cryopreservation have been highly successful (Thomassen and Farstad, 2009), other advanced technologies have been exceptionally inadequate for obtaining high rates of in vitro embryo development in the dog (Chastant-Maillard et al, 2010). For starters, the IVM rates of canine oocytes are very low compared to results obtained in other domestic species (Otoi et al, 2000;Galli and Lazzari, 2008;Bukowska et al, 2012). Canine oocytes collected from anoestrous ovaries exhibit very low frequencies (10-20%) of maturation to the MII stage after 72-96 h of culture (Luvoni et al, 2005;Songsasen and Wildt, 2007), while the IVM rate of oocytes from pre-ovulatory follicles only reaches about 30% (Yamada et al, 1993).…”

Fighting Like Cats and Dogs: Challenges in Domestic Carnivore Oocyte Development and Promises of Innovative Culture Systems

“…To mimic these conditions, extended IVM lengths and sequential media were tested, but the optimal combination has not been found yet. Whereas IVM lasts 48 or more commonly 72 h (for a review see [37]), prolonged IVM (up to 96 h [26,38]) was also experimented, even if its benefits on maturation outcomes remained controversial. Based on the few studies that investigated embryo development after fertilization, the best IVM length seemed to be 48 h [39].…”