본 연구는 개 난자의 체외성숙율 높이기 위해 개의 발정주기가 체외성숙에 미치는영향과 체외성숙율의 효율적 향상을 위해 실험을 실시하였으며, 다음의 결과를 얻었다. 1. Anestrus, proestrus, estrus와 diestrus의 발정주기로 구분하여 MII로의 체외성숙율을 48시간과 72시간 배양후 관찰한 결과 각각 15.9%, 16.3%, 23.7%와 18.2%와 22.1%, 30.8%, 36.6%와 17.5%로 나타났다. 2. 각 발정주기별로
The aim of these experiments was to investigate in vitro nuclear maturation of canine oocyte collected from various stages of estrus cycles, Ovaries were obtained from 1 to 4 year-old mongrel bitch and minced for oocyte collection in phosphate buffered saline with 100 iu penicillin-G /sup -1/, 50 streptomycin sulphate /sup -1/ and 0.1% (w/v) polyvinyl alcohol. Cumulus-oocyte-complexes (COCs) were washed in HEPES buffered tissue culture medium (TCM)199 and in vitro matured in TCM-199 culture medium supplemented with sodium pyruvate 0.028mg/, L-glutamine 0.146mg/, penicillin G 10,000 IU/, streptomycin 0.031mg/ and 10% (v/v) fatal calf serum. COCs were in vitro matured for 48~72 hrs at 39 in humidified 5% in air atmosphere. In vitro matured oocytes were remove the cumulus cells using 0.2% (v/v) hyaluronidase. After denuding, oocyte were placed in acetic acid : methanol : chlorform solusion (3:6 : 1.5 v/v) for 30 sec and acetic acid: ethanol(1:3 v/v) for 48hrs fixation. Nuclear maturation was classified to GV, GVBD, MI, MII and degenerate oocyte under microscopy after 1% aceto-orcein stain. In vitro maturation rates at 48hrs were not significantly difference among the oocytes collected from different stage of estrus at 15.9%, 16.3%, 23.7% and 18.2% for anestrus, proestrus, estrus and diestrus. However, the oocytes maturation(36.6%) of collected from estrus ovaries were significantly different from oocytes derived from proesturs, diestrus and anestrus ovaries(30.8%, 17.5% and 22.1%; p<0.05). The overall in vitro maturation rates were significantly higher (p<0.05) in 72hrs culture than 48hrs culture system. In summary, there was a tendency for higher in vitro maturation rates with the oocyte collected from estrus ovary than other stages of estrus. Also, for nuclear maturation, in vitro culture of oocyte for 72hrs was better than 48hrs culture.