Momozawa Kenji, Fukuda Yoshinori
School of Veterinary Medicine and Animal Science, Kitasato University, Towada, Aomori, Japan.
J Reprod Dev. 2003 Dec;49(6):507-12. doi: 10.1262/jrd.49.507.
The purpose of this study was to examine: 1) whether caffeine in the fertilization medium under mineral oil is essential for bovine in vitro fertilization by fully capacitated spermatozoa, 2) the minimum concentration of caffeine that shows an adverse effect on the motility of preincubated spermatozoa. Cumulus-oocyte complexes with heterogeneous-appearing ooplasm were matured in in vitro culture for 24 h and used for insemination. The fertilization rates of the preincubated spermatozoa introduced into the fertilization medium containing 0 mM or 5 mM caffeine were examined. The fertilization rate of the spermatozoa introduced into the medium without caffeine (final concentration of caffeine at fertilization was 0.27-0.35 mM) was significantly higher than that in the medium with 5 mM caffeine (82.4% vs 55.2%, P<0.05). When the final concentration of caffeine at fertilization was reduced ten-fold (0.02-0.03 mM), the fertilization rate was not significantly improved (86.0%). The motility of the preincubated spermatozoa introduced into the fertilization medium containing 0-5 mM caffeine was examined. The sperm motility in the fertilization medium without caffeine was significantly higher than that in the fertilization medium with more than 2 mM caffeine. These results indicate that caffeine in the fertilization medium is not essential for bovine in vitro fertilization by fully capacitated spermatozoa, and that more than 2 mM caffeine has an adverse effect on preincubated (capacitated) sperm motility.
1）矿物油覆盖下的受精培养液中的咖啡因对于经充分获能的精子进行牛体外受精是否必不可少；2）对预孵育精子活力产生不利影响的咖啡因最低浓度。将卵丘-卵母细胞复合体（其卵质外观不均一）在体外培养24小时用于授精。检测引入含有0 mM或5 mM咖啡因的受精培养液中的预孵育精子的受精率。引入不含咖啡因培养液（受精时咖啡因终浓度为0.27 - 0.35 mM）的精子的受精率显著高于引入含5 mM咖啡因培养液的精子的受精率（82.4%对55.2%，P<0.05）。当受精时咖啡因终浓度降低10倍（0.02 - 0.03 mM）时，受精率未显著提高（86.0%）。检测引入含有0 - 5 mM咖啡因的受精培养液中的预孵育精子的活力。不含咖啡因的受精培养液中的精子活力显著高于含2 mM以上咖啡因的受精培养液中的精子活力。这些结果表明，受精培养液中的咖啡因对于经充分获能的精子进行牛体外受精并非必不可少，且2 mM以上的咖啡因对预孵育（获能）精子的活力有不利影响。
