Zhang Jianying, Zhang Hangjun, Chen Yingxu
College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310028, People's Republic of China.
Toxicol In Vitro. 2006 Aug;20(5):560-6. doi: 10.1016/j.tiv.2005.09.013. Epub 2005 Nov 4.
Microcystins including leucine-arginine l-amino acid (MCLR) and arginine-arginine l-amino acid (MCRR) can inhibit several serine/threonine protein phosphatases. In this study, we focused on the efficient biomarker for analyzing toxic cyanobacteria blooms using in vitro apoptosis bioassay. We explored the existence of sensitive apoptosis induced by MCLR and MCRR on isolated lymphocytes of the crucian carp (Carassius auratus) at a low exposure level. Apoptosis was detected in vitro and was clearly distinguished by condensation of nuclear chromatin and formation of apoptotic bodies, after 2 h exposure at 1, 5, 10 nM MCLR and MCRR, respectively. Agarose gel electrophoresis further revealed DNA fragmentation (DNA ladder) caused by apoptosis. We found that MCLR and MCRR can induce lymphocyte apoptosis in a dose- and time-dependent manner with flow cytometry analysis. Our study provides the first evidence that microcystins can induce fish lymphocytes apoptosis and may impair fish immune function.
微囊藻毒素包括亮氨酸-精氨酸L-氨基酸（MCLR）和精氨酸-精氨酸L-氨基酸（MCRR），它们能够抑制多种丝氨酸/苏氨酸蛋白磷酸酶。在本研究中，我们聚焦于使用体外凋亡生物测定法来分析有毒蓝藻水华的高效生物标志物。我们探究了在低暴露水平下，MCLR和MCRR对鲫鱼（Carassius auratus）分离淋巴细胞诱导敏感凋亡的情况。分别在1、5、10 nM的MCLR和MCRR作用下暴露2小时后，在体外检测到凋亡，并通过核染色质凝聚和凋亡小体形成得以清晰区分。琼脂糖凝胶电泳进一步揭示了由凋亡引起的DNA片段化（DNA梯形条带）。通过流式细胞术分析，我们发现MCLR和MCRR能够以剂量和时间依赖性方式诱导淋巴细胞凋亡。我们的研究首次证明微囊藻毒素可诱导鱼类淋巴细胞凋亡，并可能损害鱼类免疫功能。
