Fisheries College of Huazhong Agricultural University, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Wuhan, 430070, PR China.
J Appl Toxicol. 2013 Aug;33(8):799-806. doi: 10.1002/jat.2735. Epub 2012 Mar 9.
Microcystins (MCs) can cause evident hepatic apoptosis. In vitro studies indicated that uptake of MC by isolated hepatocytes was dramatically reduced as ambient temperature dropped, and some studies presented a hypothesis that differences in core body temperatures in animals result in diverse uptake of MC, as well as different toxic effects. Thus far, however, few in vivo studies have been conducted to investigate the effects of temperature on MC-induced hepatocyte apoptosis in fish, a typical poikilotherm. In the present study, zebrafish were treated with MC-LR, an MC metabolite, at three water temperatures (12, 22 and 32 °C), and evident differences in apoptotic profiles were observed. Damage to liver ultrastructures revealed temperature-dependent early-stage patterns of apoptosis. Flow-cytometric analysis indicated that hepatocyte apoptotic rates varied with a temperature-dependent effect. The transcription levels of some apoptosis-related genes were determined using quantitative real-time polymerase chain reaction, and significantly elevated gene expressions of P53, Bcl-2, Bax and caspase-3 were found in the 12 and 32 °C groups. Results of the present study indicate that different ambient temperatures can lead to various toxic effects of MCs on hepatic apoptosis in fish.
微囊藻毒素（MCs）可引起明显的肝凋亡。体外研究表明，随着环境温度的降低，分离肝细胞对 MC 的摄取显著减少，一些研究提出了一种假设，即动物体内核心体温的差异导致 MC 的摄取不同，以及不同的毒性作用。然而，迄今为止，很少有体内研究探讨温度对鱼类（一种典型的变温动物）中 MC 诱导的肝细胞凋亡的影响。在本研究中，斑马鱼在三种水温（12、22 和 32°C）下用 MC-LR（MC 的代谢物）处理，观察到明显的凋亡谱差异。肝超微结构损伤显示出温度依赖性的早期凋亡模式。流式细胞术分析表明，肝细胞凋亡率随温度的影响而变化。采用实时定量聚合酶链反应测定了一些与凋亡相关基因的转录水平，发现 P53、Bcl-2、Bax 和 caspase-3 的基因表达在 12 和 32°C 组中显著升高。本研究结果表明，不同的环境温度可导致 MC 对鱼类肝凋亡产生不同的毒性作用。
