重金属对秀丽隐杆线虫繁殖的影响

Effects of Heavy Metals on Reproduction of Caenorhabditis elegans

为了探究重金属单独及联合暴露对秀丽隐杆线虫（Caenorhabditis elegans）繁殖的影响及其作用机制,采用96孔板液相暴露试验,以环境相关浓度（0.1-50.0μg/L）的Cd、Hg、Pb暴露同步化处理秀丽隐杆线虫,24 h后统计其怀卵数及阴门畸形率,以及连续记录72 h内子一代秀丽隐杆线虫的个体数,最后利用2×2析因设计方差分析阐明重金属的两两联合作用模式.结果表明：与对照组相比,Cd、Hg、Pb单独及联合暴露对秀丽隐杆线虫的繁殖具有显著抑制作用,ρ（Cd）为50.0μg/L、ρ（Hg）为10.0μg/L、ρ（Pb）为50.0μg/L暴露组秀丽隐杆线虫子一代数量分别降低了43.5%、33.8%、51.0%;Cd-Hg暴露组〔当ρ（Cd）、ρ（Hg）分别为50.0、10.0μg/L时〕、Hg-Pb暴露组〔当ρ（Hg）、ρ（Pb）分别为10.0、50.0μg/L时〕、Cd-Pb暴露组〔当ρ（Cd）、ρ（Pb）分别为50.0、50.0μg/L时〕秀丽隐杆线虫子一代个体数分别降低了44.7%、61.0%、53.3%.进一步研究发现,Cd、Hg、Pb单独及联合暴露会引起秀丽隐杆线虫子宫内受精卵数量降低以及产卵器阴门结构畸形率升高.2×2析因设计方差分析结果发现,Cd、Hg、Pb两两联合暴露对秀丽隐杆线虫的繁殖表现为没有交互作用或者交互方式为拮抗.研究显示,秀丽隐杆线虫子宫内怀卵数的降低是其子一代数量显著减少的主要原因,而阴门结构的损伤可能使产卵行为受损,从而进一步加剧重金属对秀丽隐杆线虫繁殖的抑制作用.

The 96-well plate liquid exposure experiment was applied to study the toxic effects of Cd,Hg and Pb alone and in binary mixtures on the reproduction of Caenorhabditis elegans and to reveal the underlying mechanisms preliminarily. Age synchronous populations of C. elegans were exposed to 0. 1-50. 0 μg/L of Cd,Hg and Pb. The egg number in the uterus and abnormal egg-laying apparatus were scored after 24 hours,and the brood size of the exposed nematodes was continuously scored for 72 hours. Finally,2 × 2factorial design was adopted to elucidate the type of joint effects. The results showed that Cd,Hg and Pb alone and in binary mixtures significantly inhibited the reproduction of C. elegans. Specifically,the brood size of C. elegans decreased by 43. 5%,33. 8% and51. 0% respectively after exposure to 50. 0 μg/L Cd,10. 0 μg/L Hg and 50. 0 μg/L Pb,while it decreased by 44. 7%,61. 0% and53. 3% respectively after exposure to Cd-Hg（ 50. 0 μg/L Cd and 10. 0 μg/L Hg,respectively）,Hg-Pb（ 10. 0 μg/L Hg and 50. 0 μg/L Pb,respectively） and Cd-Pb（ 50. 0 μg/L Cd and 50. 0 μg/L Pb,respectively）. Furthermore,the results indicated that Cd,Hg,and Pb alone and in binary mixtures reduced egg number in the uterus and enhanced the ratio of abnormal egg-laying apparatus. The factorial analyses revealed that binary mixtures of Cd,Hg and Pb either exhibited no interactions or antagonistic effects. This study suggested that the decreased brood size was predominantly attributed to the reduced egg number in the uterus,and the lesion of vulva structure could disrupt the egg-laying behavior,which further suppressed the reproduction of C. elegans.