본 연구는 북방산개구리의 난자 및 배아를 활용하여 난자성숙현상과 배아발달과정에 미치는 Cd2+의 독성효과를 조사하였다. 결과 Cd2+ 0.1ppm에서 난자의 성숙현상을 억제하였으며 Cd2+ 작용의 가역성을 조사하기 위해 3시간 동안 난자들을 Cd2+에 노출시킨 후 보통배양액으로 옮겨 17시간 배양한 결과 1ppm에서는 가역성을 나타내었으나 2.5ppm에서는 비가역적 인 손상을 주었다. 발달 중인 2세포 배아를 Cd2+의 여러 농도에 노출시킨 결과 0.1ppm에서 발달이 억제되었으며 노출시간이 길어진 32세포 시기에는 세포붕괴현상을 유발하였다. 한편, 포배기 배아를 Cd2+의 여러 농도에 노출시 켜 96시간 배양한 후 유생의 치사율 및 기형율을 대상으로 probit 분석법으로 조사한 결과 LC50은 0.1ppm, EC50은 0.08ppm, TI는 5.0을 나타내어 Cd2+은 높은 치사율을 나타내는 물질로 나타났다. 기형 양상은 척추기형이 0.05ppm에서 14.3%,꼬리기형이 0.1ppm에서 75.0%,복부기형 이 0.01ppm에서 66.7%를 나타내었고 profound형 기형이 0.1ppm에서 25.0%를 각각 나타냈으며 Cd2+ 0.1ppm에서 머리에서 꼬리까지의 성장을 억제하였다. 결론적으로 본 연구의 결과들은 Cd2+이 난자성숙, 난할 및 배아의 발달과정에 높은 독성의 효과를 가짐을 나타낸다.

This study investigates the toxic effects of Cd2+on frog (Rana dybowskii) by the determination of oocyte maturation and development of embryo exposure to different concentrations of the toxicant. The results show that Cd2+ concentration of 0.1ppm suppressed the maturation of the oocytes. To examine the reversibility of the inhibitory effects, the oocytes were exposed to the Cd2+ only for 3 hours, and then transferred to plain medium and cultured further for 17 hours. The oocytes were recovered from the toxic effect of the Cd2+ when they were exposed to 1ppm, but not to 2.5ppm of the Cd2+. The development of 2 cell embryos to 32 cell was completely suppressed at 0.1ppm and the longer the embryos were exposed to the Cd2+, the more damage appeared to the embryos and the cytolysis of the 32 cell was induced by Cd2+ at 0.1ppm. On the other hand, the embryos of blastula stage were cultured 96 hours in presence of the Cd2+ at various concentrations and were examined. The rates of mortality and malformed larvae were investigated by probit analysis. From the results of LC50 of 0.1ppm and EC50 of 0.08ppm, Tl of 5.0 was derived, which indicates Cd2+ is to be considered a teratogenic compound. Such specific malformations occurred in 14.3% as spine deformations at the 0.05ppm, in 75.0% as tail deformations at the 0.1ppm, in 66.7% as abdominal deformations at the 0.01ppm and in 26.0% as profound deformations at the 0.1ppm of Cd2+ concentration which living embryos were exposed to. Cd2+ suppressed growth to head-tail length at 0.1ppm. In conclusion, The study results reveal that Cd2+ must be considered highly toxic effect to oocyte maturation and embryonic development.

• 고선근 | Ko, Sun-Kun