@article{oai:niigata-u.repo.nii.ac.jp:00028435, author = {Kitagawa, Tokihisa and Niimura, Sueo}, issue = {1}, journal = {新潟大学農学部研究報告, 新潟大学農学部研究報告}, month = {Aug}, note = {The size of each part of porcine oocytes cultured in NCSU37 medium, NCSU37 medium whose NaCl concentration was lowered from 108.76 to 61.6 mM and NCSU37 medium containing 0.1% tunicamycin, an inhibitor of glycoprotein synthesis, was measured to investigate how the size of the perivitelline space changed as oocytes matured, and the reason(s) the size of the perivitelline space changed. The incidence of polyspermy in porcine oocytes after insemination was also observed, in order to ascertain a relationship between the size of the perivitelline space and the incidence of polyspermy. The size of perivitelline space enlarged as the time of culture was prolonged, even in the use of either medium examined. The perivitelline space in oocytes cultured in NCSU37 medium for 44 hrs was 3.9μm, but it was a significantly larger in oocytes cultured in NCSU37 medium with decreased concentration of NaCl (6.4μm) and a significantly smaller in oocytes cultured in NCSU37 medium containing tunicamycin (2.4μm). From the measurements of each part of oocytes during culture, it was suggested that the enlargement in the perivitelline space following treatment with low NaCl was attributed to reduction of the oocyte cytoplasm, while the decrease in the perivitelline space following treatment with tunicamycin was attributed to expansion of the oocyte cytoplasm. Oocytes cultured for 44 hrs in NCSU37 medium, NCSU37 medium with decreased concentration of NaCl and NCSU37 medium containing tunicamycin showed the maturation rate of 88.8, 93.7 and 87.2%, respectively, and the fertilization rate after insemination of 83.6, 87.0 and 88.2%, respectively. There were no differences in either the maturation rate or the fertilization rate seen among these three culture media. On the other hand, the incidence of polyspermy of oocytes matured in NCSU37 medium was 52.1%, which was significantly higher than 30.0% of oocytes matured in NCSU37 medium with decreased concentration of NaCl, and was significantly lower than 71.7% of oocytes matured in NCSU37 medium containing tunicamycin. From these findings, it was clarified that the higher incidence of polyspermy is closely related to the smaller perivitelline space in porcine oocytes., NaClの濃度を低くした低NaCl-NCSU37培養液およびツニカマイシン添加NCSU37培養液で培養したブタの卵丘卵母細胞複合体について、卵母細胞の各部位の大きさを計測して通常のNCSU37培養液で培養した卵母細胞のものと比較し、低NaCl処置およびツニカマイシン処置した卵母細胞の囲卵腔の大きさが変化する原因について検討した。また、媒精後の多精子侵入の頻度を観察し、ブタ卵母細胞の囲卵腔の大きさと多精子侵入の頻度との間に関係があるのか否かを検討した。囲卵腔は、いずれの種類の培養液で培養した卵母細胞においても、成熟に伴って拡大した。なお培養後44時間において、囲卵腔は、通常のNCSU37培養液で成熟させた卵母細胞では3.9μmあったが、低NaCl-NCSU37培養液で成熟させた卵母細胞では有意に拡大して6.4μmになるとともに、ツニカマイシン添加NCSU37培養液で成熟させた卵母細胞では有意に縮小して2.4μmになった。一方、卵母細胞の各部位の計測から、低NaCl-NCSU37培養液で培養した卵母細胞で囲卵腔が大きくなったのは、卵母細胞の細胞質が収縮したことによるものと思われた。また、ツニカマイシン添加NCSU37培養液で培養した卵母細胞の囲卵腔が小さくなったのは、卵母細胞の細胞質が拡大したことによるものと思われた。一方、NCSU37培養液、低NaCl-NCSU37培養液およびツニカマイシン添加NCSU37培養液で44時間培養した卵母細胞の成熟率および媒精後の受精率は、それぞれ88.8、93.7、87.2%および83.6、87.0、88.2%であり、これら3種の培養液の間で成熟率と受精率に相違はみられなかった。また多精子侵入の頻度は、NCSU37培養液で成熟させた卵母細胞では52.1%であったが、低NaCl-NCSU37培養液で成熟させて囲卵腔が大きくなった卵母細胞では有意に低く30.0%であるとともに、ツニカマイシン添加NCSU37培養液で成熟させて囲卵腔が小さくなった卵母細胞では有意に高く71.7%であった。以上の結果から、ブタ卵母細胞の囲卵腔の大きさと多精子侵入の頻度との間には密接な関係のあることが確認された。}, pages = {21--26}, title = {Relationship between the Size of Perivitelline Space and the Incidence of Polyspermy in Porcine Oocytes}, volume = {59}, year = {2006} }