Reprod. Nutr. Dev. 42 (2002) 265-273
DOI: 10.1051/rnd:2002024

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

Luisa Bogliolo^a, Maria Teresa Zedda^a, Sergio Ledda^b, Giovanni Leoni^b, Salvatore Naitana^b and Salvatore Pau<sup>a

a</sup>  Obstetrics Section of the Institute of General Pathology, Pathological Anatomy and Veterinary Obstetrics-Surgery Clinic, 07100 Sassari, Italy
^b  Department of Animal Biology, University of Sassari, 07100 Sassari, Italy

(Received 1 February 2002 ; accepted 30 May 2002)

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.

Key words: bitch / oocyte / in vitro maturation / oviductal cells / oestrous cycle

Correspondence and reprints: Luisa Bogliolo
    e-mail: nuvola@ssmain.uniss.it

© INRA, EDP Sciences 2002