Abstract
This study investigated the effects of superoxide dismutase (SOD) on lipid peroxidation and fertilizing ability in vitro of boar spermatozoa frozen-thawed. The percentages of motile sperm were highest when SOD of 10 units/$m\ell$ was added to washing medium for spermatozoa. However, the rates of motile sperm were not significantly different in different concentrations of SOD. On the other hand, the motile rates of sperm washed with SOD were lower in sperm inculbated for 120 min than 30 min regardless of the different concentrations of SOD. The percentage of spermatozoa that reached acrosome reaction were increased with incubation periods prolonged. No significant differences, however, were observed in acrosome reaction rates between sperm incubated with and without SOD supplementation for 0, 60 and 120 min. When oocyies inseminated with different concentrations of SOD, the penetration rates were significantly (P＜0.05) higher in medium with 1 unit/$m\ell$ than 0, 10 and 100 units/$m\ell$ of SOD. However, the proportions of polyspermit oocytes were significantly (P＜0.05) lower in medium with 10 and 100 units/$m\ell$ than 0 unit/$m\ell$ of SOD. In another experiment, the sperm suspension were also treated with different concentrations of SOD and were assayed far sulfhydryl(-SH) group content. In the groups treated with 100 units/$m\ell$ of SOD, sperm-SH group were higher than another groups. However, sperm-SH group content were not siginificantly different in spermatozoa treated with different concentrations of SOD. Under the same conditions, the lipid peroxidation of sperm was evaluated on the basis of malondialdehyde production. The addition of SOD to sperm suspension decreased the formation or malondialdehyde. However, there were not significantly different in sperm treated with different concentrations of SOD. The activity of sperm binding to zona pellucida was also evaluated through binding to salt-stored porcine oocytes. The sperm binding to zona pellucida were gradually increased with SOD concentrations added. The number of spermatozoa binded to zona pellucida were significantly (P＜0.05) higher in medium with 100 units/$m\ell$ than 0 units/$m\ell$ of SOD. These findings suggested that SOD cause an enhancement penetrarion ability and sperm zona binding in boar spermatozoa frozen-thawed.
본 연구는 superoxide dismutase (SOD)가 동결-응해 돼지정자의 lipid peroxidation과 체외수정능력에 미치는 영향을 검토하였다. 그 결과 동결-응해 정자는 10 units/$m\ell$의 SOD가 첨가된 배양액에 의해 처리했을 때 가장 높은 정자생존율을 나타냈으나 서로 다른 농도에 의한 차이는 인정되지 않았다. 그러나 SOD농도에 관계없이 정자처리 직후의 생존율은 120분간 배양 후에 비해 유의적(P＜0.05)으로 높은 생존율을 나타냈다. 또한 정자처리 후 배양시간이 0, 60 및 120분으로 길어짐에 따라 정자의 첨체반응 유기율이 증가하였지만 SOD 첨가 또는 무첨가구 사이에서 유의적인 차이는 인정되지 않았다. 한편, 체외수정시 1 unit/$m\ell$의 SOD를 첨가한 경우 0, 10 및 100 units/$m\ell$ 첨가시 보다 유의적(P＜0.05)으로 높은 정자침입율을 나타냈으며, 10과 100 units/$m\ell$의 SOD 첨가시 낮은 다정자 침입율을 나타냈다 (P＜0.05). 정자의 peroxidation은 malondialdehyde의 생성에 기초를 두고 평가하였는데 SOD 무첨가에 비해 첨가농도가 높아질수록 malondialdehyde의 생성이 낮아졌지만 유의적인 차이는 인정되지 않았다. 또한 동결-융해된 정자는 sulfhydrl(-SH) group의 용량을 측정한 결과 SOD무첨가시 보다 첨가시 높은 용량이 측정되었지만 유의적인 차이는 인정되지 않았다. 한편, 동결-융해된 정자가 체외에서 성숙시킨 난자의 투명대에 접착하는 정도를 평가한 결과 SOD 무첨가 보다는 첨가농도가 높아짐에 따라 접착정자수가 증가하였으며 100 units/$m\ell$ 첨가시 유의적(P＜0.05)으로 높은 접착정자 수를 나타냈다 본 연구의 결과로부터 SOD는 돼지 동결-융해정자에 있어서 난자의 투명대 접착능력의 증가와 함께 체외수정능력 향상에 영향을 미치는 것으로 나타났다.