Post-ejaculation of sperms into the female reproductive tract, acquisition of sperm capacitation is an essential step in the fertilization process. Accordingly, during in-vitro fertilization, the successful fertilization requires necessarily induction of capacitation in the retrieved sperms. To date, many candidate substances have been considered as capacitation inducers. However, there were no reports about the comparison of efficiency inducing sperm capacitation among diverse capacitation inducers. Therefore, we tried to determine an inducer showing the best capacitation performance in mouse sperms by comparing the preimplantation development of in-vitro-fertilized embryos using sperms experiencing capacitation by a variety of capacitation inducers. For these, calcium, progesterone, bovine serum albumin (BSA), heparin, lysophosphaticylcholine (Lyso-PC) were used as candidate capacitation inducers. Optimized concentration of each inducer were determined by accessing ratio of sperms experiencing acrosome reaction using coomassie G-250 blue staining. Subsequently, in vitro fertilization was performed using sperms incubated in each optimized concentration inducer. The ratio of fertilized oocytes was observed. As the results, Calcium at 2.7 mM and 0.3% (w/v) BSA showed the highest fertilization rates compared to 15 μM progesterone, 50 mM heparin, and 100 μM Lyso-PC. From these results, we found that 2.7 mM calcium and 0.3% (w/v) BSA were the most effective sperm capacitation inducers of mouse sperm for in vitro fertilization. From these results, we could identify that, among diverse sperm capacitation inducers, 2.7mM calcium and 0.3% (w/v) BSA were the most effective inducers for in vitro fertilization.

Mammalian fertilization is a complex cascade process consisting of sperm migration through the female reproductive tract, physiological changes to sperm such as sperm capacitation and acrosome reaction, and sperm-egg interaction in the oviduct in vivo. On the other hand, in vitro fertilization (IVF) is a process by which egg cells are fertilized by sperm outside the body: in vitro. IVF has been used for a variety of purposes in reproductive biotechnology for human and animals. The discovery of sperm capacitation in 1951 promoted the development of IVF technology. In the initial stage of IVF, sperm capacitation in preincubation medium was shown to be essential to fuse with eggs. Besides, sperms should detour some of the in vivo regulations for IVF. This review introduces a general mammalian fertilization process, including sperm capacitation, removal of cumulus matrix, acrosome reaction, and sperm-egg fusion and focuses on the roles of key biochemical molecules, signal mechanisms, and genes involved during IVF and novel results of sperm-oocyte interaction elucidated in various gene-knockout mice models.

The objective of this study was to examine the effect of various discontinuous Percoll washing conditions on sperm capacitation status and sperm survival. Frozen epididymal sperm samples from 3 bulls (0.5 ml plastic straws, 6% glycerol in egg yolk- Tris-glycerol extender) were thawed in 37℃ water bath for 1 min. To rule out individual variation, 3 sperm samples were mixed after thawing. The mixed samples then were randomly allocated to 12 treatment groups. Briefly, the spermatozoa were centrifuged for three different time lengths (10, 20, and 30 min) at two gravities (300 X g and 700 X g) through two concentrations of discontinuous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll and 2 ml 90%: 2 ml 45% Percoll to remove extender, debris, and dead spermatozoa. Sperm capacitation status and sperm survival were evaluated using combined Hoechst 33258 and chlortertracycline fluorescence staining assay. The acrosome reacted spermatozoa (AR pattern), uncapaciated spermatozoa (F pattern) and sperm survival were significantly correlated with centrifugation time (p< 0.01). Significantly decreased F pattern observed as centrifugal time increased. As centrifugal time increased, spermatozoa with F pattern decreased and spermatozoa showing AR pattern increased. Moreover, the dead spermatozoa were significantly stimulated in time-dependent manner. However, there were no significant differences in various force of centrifugation and Percoll volume. These results suggest that only centrifugation time significantly affects sperm capacitation status and sperm survival.

본 연구는 ICSI후 돼지 난자의 활성화 처리와 ICSI전 주입정자의 수정 능력 획득 유기효과를 구명하기 위하여 실시하였다. ICSI후 ethanol, cycloheximide 그리고 ethanol과 cycloheximide를 병용처리 시 난할율과 배반포배 발달율이 대조구와 처리 구간에 유의적인 차이가 없었다(p<0.05). 그러나 ICSI전 caffeine과 Ca-ionpphre로 주입정자의 수정능력 획득 유기 처리 시 난할율과 배반포배발달율 모두 처

This study was aimed to develope the new method for bovine sperm capacitation through testing and combinating factors relating to sperm capacitation. For verifying the efficiency of this method on inducing capacitation, in vitro fertilization was carried out. The results obtained were as follows: When pHs of HBS /PR for sperm-washing were 5.99, 6.38, 6.78, 7.10, 7.40, 7.69, 8.15, 8.45 and 8.83, variances between light absorhance differences obtained from sperm pre-washing solution and post-washing solution(VADs) were 0.000, 0.001, -0.001, -0.005, -0.005, -0.021,-0.017,-0.016,and-0.036, respectively. There were significant decreases of VADs in pH 7.69 and pH 8.83. When sperm were firstly, secondly, and thirdly washed with HBS /PR, VADs were -0. 024, - 0.006, and - 0.004, respectively. There was significant decrease of VAD in 1st sperm-washing. When washed-sperm were secondly washed with HBS /PR supplemented with no (con-trol), heparin, CSA, PC12, and BSA, VADs were 0.009, -0.024, -0.008, -0.009, and 0.014, respectively. When the sperm were thirdly washed with HBS /PR with no(control), heparin, CSA, PC12 and BSA, VADs were 0.020, -0.007, 0.005, 0.006, and 0.019, respectively. Only heparin treatment showed the negative values of VADs in 2nd and 3rd sperm-washing. Of oocytes cultured with sperm which were repeatedly washed with heparin and high pH, 52% (57/110) were cleaved over 2 cell stage. However, percent of oocytes parthenogenetically divided was 5%(2 /42).