五氯酚对稀有鮈鲫胚胎毒性效应研究

研究五氯酚(PCP)对稀有鮈鲫(Gobiocypris rarus)胚胎的致畸和毒性效应.以7.5,30,60,120,250μg/L5个浓度的PCP对0hpf(hpf,受精卵孵出时间)的稀有鮈鲫胚胎进行暴露染毒,同时设置空白对照组、二甲基亚砜溶剂对照组和雌二醇(EE2,2.5ng/L)阳性对照组.在立体显微镜下观察整个胚胎的发育过程,统计胚胎的孵化率、96hpf相对存活率和各时期的畸形率,并利用半定量RT-PCR检测胚胎中CYP1A基因和p53基因mRNA的表达.结果表明,PCP暴露能延迟稀有鮈鲫胚胎发育,并造成胚胎卵凝结、心包囊肿、脊柱弯曲等多种畸形甚至死亡.随着PCP暴露浓度的升高,稀有鮈鲫胚胎的孵化率和96hpf相对存活率降低,各时期的畸形率增加,并呈现一定的浓度效应.稀有鮈鲫胚胎CYP1A基因和p53基因mRNA表达被显著诱导,并随PCP浓度的升高而增加.PCP对稀有鮈鲫胚胎发育表现为显著的毒性效应.稀有鮈鲫胚胎孵化率、96hpf相对存活率、各时期畸形率及CYP1A基因和p53基因的诱导表达可以作为评价PCP毒性作用的敏感指标.

Toxic effects of pentachlorophenol on the Chinese rare minnow embryos

The carcinogenicity and toxicity of pentachlorophenol (PCP) exposure on the Chinese rare minnow (Gobiocypris rarus) embryos were investigated. G. rarus embryos at 0 hour past fertilization (hpf) were exposed to PCP at different concentrations (0, 7.5, 30, 60, 120, 250μg/L). DMSO(<0.01%,V/V) and 17a-ethynylestradiol (EE2, 2.5ng/L) were set as solvent control and positive control, respectively. The embryonic development was observed under the stereomicroscope. The hatching rate, relative survival rate at 96 hpf, and deformity rate through the entire embryos developmental process were calculated. Furthermore, the mRNA expressions of CYP1A and p53 gene were analyzed by semi-quantitatively RT-PCR. PCP exposure resulted in delayed embryonic development, condensation of embryonic eggs, formation of pericardial cysts, curvature of the spine or even death. The hatching rate and relative survival rate at 96 hpf were reduced while deformity rate were increased in a dose dependent manner of PCP. The mRNA level of CYP1A and p53 in embryos also were significantly up-regulated with increasing PCP concentration. PCP had significant toxic effects on G. rarus embryos. The hatching rate, relative survival rate at 96 hpf, malformation rate, CYP1A and p53 expression levels can be used as sensitive biomarkers to evaluate the toxic effects of PCP exposure on fish embryos.