In 1951, Colin Russell Austin and Min Chueh Chang identified “capacitation”, a special process involving ejaculated spermatozoa in the female reproductive tract. Capacitation is a phenomenon that occurs in vivo , but almost all knowledge of capacitation has been obtained from in vitro studies. Therefore, numerous trials have been performed to establish in vitro capacitation methods for various studies on reproduction. Although a series of studies have been conducted to develop an optimal protocol for inducing capacitation, most have focused on identifying the appropriate chemical compounds to induce the capacitation of boar spermatozoa in vitro. Therefore, the purpose of this study was to identify the optimal incubation time for inducing capacitation in vitro. Duroc semen was incubated for various periods (60, 90, and 120 min) to induce capacitation. Sperm function (sperm motility, motion kinematic parameters, and capacitation status) was evaluated. The results showed that total sperm motility, rapid sperm motility, progressive sperm motility, curvilinear velocity, and average path velocity significantly decreased in a time-dependent manner. However, the capacitation status did not show any significant changes. Taken together, these results indicate that an incubation time of more than 60 min suppresses sperm motility and motion kinematic parameters. Therefore, we suggest that 60 min may be the best incubation time to induce capacitation without negative effects on sperm motility and motion kinematics in boar spermatozoa in vitro.

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 prediction of male fertility is of paramount importance for breeding animal herds when artificial insemination is applied. While the male fertility assays provide valuable quantitative data, they yield limited information concerning the functional competence of the spermatozoa. The objective of this study was to standardize a method for predicting in vivo fertility in bulls using the capacitation status that was assessed by chlortetracycline (CTC) staining. To optimize the capacitation process, sperm were treated with various concentrations of heparin (0, 10, 20, 50, and 100 μg/mL) and incubated for 10, 20, and 30 min each at 39℃ in 5% CO2. We found that maximum capacitation condition obtained from 10 μg /mL heparin treated sperm cells for 20 min (p<0.05). Optimized methods were used to determine the fertility of 17 batches of frozen bull semen representing a wide range of field fertility levels as indicated by non-return rates (NRR) (35.29% 93.18%). There was no significant correlation between NRR and the percentage of capacitated spermatozoa (B type) and non-capacitated spermatozoa (F type). However, acrosome reacted spermatozoa (AR type) was significantly correlated with NRR (p<0.01). To determine the normal range for the AR type, lower limits of the AR (%) were established as 23% for low fertility (NRR < 75%) using receiver operating characteristic curve. The overall accuracy of the assay was 88.24% for low fertility, sensitivity and specificity were 81.82 and 100%, respectively. These results indicate that capacitation status as measure by CTC staining is a useful predictor of male fertility. Therefore, low and high fertility bulls can be identified primarily by the functional capacitation status.

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.

The objective of this study was to investigate the effect of storage time on fresh boar semen in Androhep and Beltsville Thawing Solution (BTS). Boar semen samples extended in each extender were stored at 17℃ up to 4 days. Sperm motility kinematics was evaluated by computer assisted sperm analyzer (CASA) and capacitation status by chlortetracycline (CTC)/Hoechst 33258 staining. Sperm motility (%) was not decreased during storage in BTS and Androhep. No significant difference between extenders was observed. Only significant differences in kinematic parameters on linearity during storage were found. The percentage of dead sperm significantly decreased during storage (p<0.05). Also the percentage of noncapacitated, capacitated, and acrosome-reacted sperm significantly modified during storage (p<0.05). However, there was no significant difference between extenders except proportion of capacitated sperm. This finding supported that modification in these parameters was not significantly different between extenders during this short-term storage. Our finding strongly indicated that both Androhep and BTS maintained favorable conditions for motility, motility kinematics, and capacitation status during short-term storage. Despite modifications in some parameters were apparent during sperm storage in extenders, these may not affect the fertilizing capacity of boar semen.

본 연구는 정액의 보존 기간 동안 정액의 질적 변화를 알아보고자 시행하였다. 돼지 정액을 Beltsville Thawing Solution (BTS)에 희석한 후 17'C 에서 5일 동안 보존하였다. 보존 기간 동안 정자의 운동성(%)과 linearity는 3일째부터 유의하게 감소하였으나, 다른 운동 역학 변수에서는 유의적 변화를 나타내지 않았다. 또한, 5일 동안 정액을 보존할 경우 첨체의 온전성에도 변화가 없었다. 그러나 제 4일째부터 첨체 변화가 야기된 정자는 유의적으로 증가하였으나, 수정능 획득이 일어난 정자는 유의적으로 감소하였다. 정액의 보존 기간 동안 첨체의 온전성의 유의적 변화가 없었다. 즉, 보존 기간 3일동안 정자의 질적 운동성 및 첨체 온전성에는 유의적인 변화가 없었으므로 상업용 돼지 액상정액은 17'C 에서 적어도 3일간 수정능력을 만족스럽게 유지함을 보여준다.

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

The present study was performed to investigate the effects of caffeine and heparin on capacitation and acrosome reaction of bovine spermatozoa, effects of antisperm antibodies on acrosome reaction of bovine spermatozoa. The rates of acrosome reaction in control group, caffeine treated group, heparin treated group, caffeine-heparin complex treated group were 40.3, 54.3, 63.3, 72.3%, respectively and there were significant differences among the groups(p<0.01), especially higher in caffeine-heparin complex treated group than the others. The rates of acrosome reaction of antisperm antibodies serum supplemented groups(5, 10 and 20%) were 60.4, 48.9 and 37.1%, respectively and there were significant differences among the groups(p<0.0l), and the more increases in serum concentrations, the more decreases in acrosome reaction, but this phenomenon was not seen in fetal calf serum supplemented group and heifer serum group. When the serum concentration was 5%, the rates of acrosome reactions were significantly lower in fetal calf serum supplemented group than heifer serum group and in antisperm antibodies serum group(p<0.01), and there were no significant differences between heifer serum group and antisperm antibodies serum group(p<0.01). When the serum conecntrations were 10%, 20%, the rates of acrosome reactions were significantly lower in antisperm antibodies serum supplemented group than in fetal calf serum group and in geifer serum group(p<0.01), and there were no significant differences between fetal calf serum group and heifer serum group(p<0.01). These results indicate that caffeine-heparin complex treatment is very effective for inducing acrosome reaction of bovine spermatozoa and that antisperm antibodies block acrosome reaction.

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).