Influence of co-culture with oviductal epithelial cells on in vitro maturation of canine oocytes

Abstract

-The process of oocyte maturation in the canine species is unique among mammals: oocytes are immature at ovulation and the resumption and progression of meiotic maturation occur in the oviduct. This study was performed to investigate (i) the effect of co-culture with infundibulum and ampullar oviductal epithelial cells on the in vitro maturation of canine oocytes and (ii) the culture time necessary to reach full meiotic maturation. For this purpose the oocytes, collected from the ovaries of bitches undergoing ovariectomies, were divided into three groups and cultured for 48 and 72 h with the following systems: (A) TCM 199 + 10% oestrus bitch serum + FSH (0.1 IU . mL -1 ), LH (0.1 IU . mL -1 )+ progesterone (1 mg . mL -1 ) + oestradiol (1 mg.mL -1 ) + cysteamine (100 mM); (B) medium A plus infundibulum cells; (C) medium A plus ampullar cells. Infundibulum and ampullar cells were recovered from the oviducts of bitches at the oestrus stage of their cycle. The results showed that after 48 h of incubation, a significantly higher meiotic resumption (P < 0.01) was observed in the oocytes cultured with infundibulum (59%) and ampullar cells (60.0%), than in the control group (40.0%). There was also a significantly (P < 0.01) higher meiotic progression to the MII in systems B and C (15.6% and 16.7%) than in system A (4.0%). After 72 h of culture, the percentages of meiotic resumption and progression were unchanged. These results showed that both the infundibulum and the ampullar oviductal epithelial cells positively influence the meiotic resumption and progression of canine oocytes and that 48 h are sufficient for the completion of nuclear maturation. bitch / oocyte / in vitro maturation / oviductal cells / oestrous cycle Reprod. Nutr. Dev. 42 (2002) 265-273 265

The effect of oviductal cells on in vitro maturation of canine oocytes in different culture media

“…It is well known that the progesterone level increases before ovulation and maturation occurs after 3-4 days in dogs, whereas in other species, ovulation occurs in the preovulatory follicular fluid (12). In this study, it is thought that lack of MII stage oocytes could be attributed to the anestrus stage and lack of progesterone effects.…”

“…Many researchers are still striving to establish optimal culture conditions and limited success rates in IVM are obtained for canine oocytes and embryos (5,12).…”

Size of the donor follicle, but not stage of reproductive cycle or seasonality, influences meiotic competency of selected domestic dog oocytes

“…The incidence of 80% nuclear maturation (from the >2 mm diameter follicles) was easily >50% higher than rates reported when oocytes were not categorized on the basis of donor follicle size (Bogliolo et al, 2002;Bolamba et al, 2002;Otoi et al, 2002;Songsasen et al, 2002Songsasen et al, , 2003Luvoni et al, 2003;Rodrigues and Rodrigues, 2003;WiUingham-Rocky et al, 2003). The incidence of Mil (15%-30%) in smaller size follicles was quite comparable to a host of other reports for this species (Nickson et al, 1993;Yamada et al, 1993;Otoi et al, 2001;Willingham-Rocky et al, 2003).…”

“…It is generally accepted that lack of an effective procedure to in vitro mature oocytes is the major impediment to using embryo transfer in the dog (see reviews, Farstad, 2000;Luvoni, 2000). Since the first report on in vitro maturation of domestic dog oocytes in 1976 (Mahi and Yanagimachi, 1976) and despite significant efforts (Yamada et al, 1993;England, 1998, 1999;Saint-Dizier et al, 2001;Bogliolo et al, 2002;Bolamba et al, 2002;Otoi et al, 2002;Songsasen et al, 2002Songsasen et al, , 2003Luvoni et al, 2003;Rodrigues and Rodrigues, 2003;Willingham-Rocky et al, 2003), little progress has been made in developing a culture system that will consistently achieve nuclear maturation in canine oocytes. On average, only 15%• 20% of ovarian oocytes complete nuclear maturation after 48-72 hr of culture.…”

Influência do fator de crescimento semelhante à insulina I (IGF-I) adicionado ao meio fluido sintético de tuba uterina (SOF) sobre a maturação in vitro de oócitos caninos (Canis familiaris)

“…Além do TCM são descritos os meios TYH (Krebs-Ringer bicarbonato modificado), TALP (tyrode modificado) e BWW (Biggers-WhittenWhittingham) que podem ser suplementados com proteína, hormônios, soro e células da tuba uterina (LUVONI, 2000;BOGLIOLO et al, 2002). Hewitt, Watson e England (1995), estudaram os meios suplementados com FSH, hCG e estradiol para cultivar oócitos em folículos pré antrais avançados e antrais precoces.…”