UVB辐射导致斑马鱼早期胚胎发育异常和DNA损伤的初步研究

Teratogenesis and DNA damage of UVB irradiation on zebrafish' early stage embryos

为研究UVB辐射对斑马鱼(Danio rerio)早期胚胎发育的影响,采用波长302nm,强度分别为120、240、310、420μW/cm2的UVB照射斑马鱼早期发育阶段的胚胎,照射时间分别为1、3、5、10min,用于研究UVB照射对形态学及DNA损伤的影响;将原肠期、体节期胚胎及孵化后2d仔鱼经UVB照射,设立未经UVB照射组为对照组,观察记录UVB照射后胚胎发育情况,统计死亡率、畸形率;应用单细胞凝胶电泳(SCGE)技术检测不同UVB照射条件对DNA损伤的影响。结果表明:(1)UVB照射对斑马鱼早期胚胎发育形态有明显的影响,能够造成尾部弯曲、围心腔扩大、脊柱扭曲等多种畸形甚至死亡;(2)在检测UVB照射与DNA损伤的关系时,发现UVB照射对胚胎细胞中的DNA能够产生比较明显的损伤,且DNA损伤随照射强度的增加和照射时间的延长而加剧。在所研究的3个发育阶段中,原肠胚受损最为严重,但未发现明显的剂量累积效应。结论认为,UVB照射对斑马鱼早期胚胎发育有明显影响,不同的照射强度和时间造成的影响差异显著;不同发育阶段的斑马鱼胚胎对UVB照射的耐受程度也不同。

The impact of UVB irradiation on embryonic development were studied with early embryos of zebrafish （Danio rerio）. Gastrula stage embryos were exposed to different UVB-radiation intensities of 120 μW/cm^2, 240 μW/cm^2, 310 μW/cm^2 and 420 μW/cm^2 for 1 min, 3 min, 5 min and 10 min. Gastrula stage embryos, somite stage embryos and larvae of two days were exposed to UVB of 420 μW/cm^2 for 5 min to investigate the UVB irradiation impact on embryos of different development stages. Groups without radiation were set up as control. After irradiation, the process of embryonic development was recorded. The mortality, malformation rate and severe malformation rate were counted. DNA damage was detected by single-cell gel electrophoresis （SCGE）. The results were as follows： （ 1 ） Several kinds of malformation such as tail bending, enlarged pericardial sacs, severe spinal distortion oecured in the early stage embryos of zebrafish exposed to UVB irradiation, some of which even died. When embryos were exposed to low intensity UVB-radiation （ 120 μW/cm^2 ）, malformation rate increased with the increase of irradiation time, but mortality rate remained in a relatively stable range. And both of malformation and mortality rate of embryos rose with the increase of intensity or exposure time under large doses of UVB-radiation of 240 μW/cm^2, 310 μW/cm^2 and 420 μW/cm^2. （ 2 ） UVB radiation could induce significant DNA damage in embryos of zebrafish, and the damage degree was related to exposure time and irradiation intensities. Damage at gastrula stage is the most serious compared with the other two stages. However, obvious dose accumulation effect was not found. The conclusion is that UVB radiation may induce significant DNA damage at the early stage embryos of zehrafish. The damage significantly related to exposure time and irradiation intensities. The sensitivities of embryos at different stages were different.