Departamento de Genética e Morfologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF Brazil.
Genet Mol Biol. 2010 Oct;33(4):750-5. doi: 10.1590/s1415-47572010000400023. Epub 2010 Dec 1.
Studies of genotoxicity in fish caused by cyanobacterial microcystins can be useful both in determining the sensitivity of native species, as well as comparing exposure routes. The genotoxicity caused by the microcystins LR and LA from a bloom collected in a eutrophic lake, was revealed in the fish Astyanaxbimaculatus, a native species from South America. LC50 (72 h) was determined as 242.81 μg L (-1) and LD50 (72 h) as 49.19 μg kg (-1) bw. There was a significant increase of DNA damage in peripheral erythrocytes, following intraperitoneal injection (ip) with tested concentrations of 24.58 μg kg (-1) bw and 36.88 μg kg (-1) bw, as well as through body exposure to a concentration of 103.72 μg L (-1) . Micronucleus (MN) induction was observed after ip injections of 24.58 μg kg (-1) bw and 36.88 μg kg (-1) bw for 72 h, as well as following body exposure for 72 at 103.72 μg L (-1) . Thus, both exposure routes resulted in MN induction and DNA damage. Apoptosis-necrosis testing was carried out only by ip injection with concentrations of 24.58 μg kg (-1) bw and 36.88 μg kg- 1 bw. Exposure to microcystins at lower concentrations induced more apoptosis than necrosis in peripheral erythrocytes, whereas exposure at higher concentrations gave rise to both conditions. Thus, Astyanax bimaculatus can be considered as a species sensitive to the genotoxic effects caused by microcystins.
藻类微囊藻毒素对鱼类的遗传毒性研究，对于确定本地物种的敏感性以及比较暴露途径都非常有用。从富营养化湖泊中采集的水华产生的微囊藻毒素 LR 和 LA 对原产于南美的鱼类 Astyanax bimaculatus 产生了遗传毒性。LC50（72 小时）为 242.81μg/L，LD50（72 小时）为 49.19μg/kg bw。经腹腔注射（ip）测试浓度为 24.58μg/kg bw 和 36.88μg/kg bw 以及暴露于浓度为 103.72μg/L 时，外周血红细胞的 DNA 损伤明显增加。在注射 24.58μg/kg bw 和 36.88μg/kg bw 72 小时后，以及在暴露于 103.72μg/L 72 小时后，观察到微核（MN）的诱导。因此，两种暴露途径均导致 MN 诱导和 DNA 损伤。仅通过腹腔注射浓度为 24.58μg/kg bw 和 36.88μg/kg bw 进行了凋亡-坏死检测。在较低浓度下接触微囊藻毒素会诱导外周血红细胞更多的凋亡而不是坏死，而在较高浓度下则会同时产生这两种情况。因此，Astyanax bimaculatus 可以被认为是对微囊藻毒素引起的遗传毒性敏感的物种。
