Recovery of reproductive function of female zebrafish from the toxic effects of microcystin-LR exposure
Recovery of reproductive function of female zebrafish from the toxic effects of microcystin-LR exposure
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雌性斑马鱼的生殖功能从微囊藻毒素-LR暴露的毒性作用中恢复
DOI：
10.1016/j.aquatox.2019.105240
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发表时间：
2019
影响因子：
4.5
通讯作者：
Xuezhen Zhang
中科院分区：
文献类型：
--
作者：
Atufa Kawan;Tongzhou Zhang;Wanjing Liu;Hina Mukhtar;Chunhua Zhan;Xuezhen Zhang
鱼类对微囊藻毒素（MCs）有很强的抵抗力，这是一种环七肽氰毒素，被称为内分泌干扰化学品（EDCs），在蓝藻水华期间释放，许多实验室和现场研究发现，鱼类的肝脏从MCs暴露中恢复。研究了微囊藻毒素-LR（MC-LR）暴露对成年斑马鱼（Danio rerio）生殖功能恢复的影响。因此，成年雌性斑马鱼暴露于0、1和50 μg/L的MC-LR 21天，并转移到无MC的水中21天以研究恢复。MC-LR暴露后，观察到性腺中的明显组织学病变，成熟卵母细胞的百分比降低，产卵数量减少，受精率和孵化率降低。MC-LR暴露增加了雌性斑马鱼体内17β-雌二醇（E2）、睾酮（T）和卵黄蛋白原（VTG）的含量。下丘脑-垂体-性腺（HPG）轴部分基因转录水平发生了显著变化。MC-LR暴露组17βhsd和cyp 19 a蛋白水平显著升高。然而，我们的实验室观察也表明，从微囊藻毒素暴露转移到无毒素水中并饲养21天的斑马鱼表现出几乎完全恢复的生殖功能，包括组织结构，增加成熟卵母细胞和产卵的百分比，稳定的激素水平，良好平衡的转录和翻译水平。这些结果表明，MC-LR暴露后，斑马鱼的生殖损伤也是可逆的，与鱼类不同研究中观察到的肝脏恢复相似。今后应开展研究，以更好地了解鱼类从微囊藻毒素暴露中恢复的机制。
Fish has a strong resistance to microcystins (MCs), cyclic heptapeptide cyanotoxins, known as endocrine disrupting chemicals (EDCs) which are released during cyanobacterial blooms and many laboratory and field studies have found the hepatic recovery of fish from the MCs exposure. The aim of the present study was to investigate the recovery mechanisms of reproductive function of adult zebrafish (Danio rerio) from microcystin-LR (MC-LR) exposure. Therefore, adult female zebrafish were exposed to 0, 1 or 50 μg/L of MC-LR for 21days and transferred to MC free water for another 21 days to investigate the recovery. After MC-LR exposure, marked histological lesions in the gonads, decreased the percentage of mature oocytes, decreased number of spawned eggs, decreased fertilization and hatching rates were observed. MC-LR exposure increased the concentration of 17β-estradiol (E2), testosterone (T) and vitellogenin (VTG) in female zebrafish. Some gene transcriptions of the hypothalamic-pituitary-gonad (HPG) axis significantly changed. The protein levels of 17βhsd and cyp19a remarkably increased in the MC-LR exposure groups. However, our laboratory observation also indicates that zebrafish transferred from microcystin exposure to toxin-free water and reared for 21 days exhibited a nearly complete recovery of reproductive functions, including histological structure, increased the percentage of matured oocytes and spawned eggs, stable hormone levels, well-balanced transcriptional and translational levels. These results indicate that after MC-LR exposure, the reproductive impairments in zebrafish are also reversible likewise hepatic recovery seen by different studies in fish. Future studies should be conducted to explore a better understanding of the recovery mechanisms of fish from microcystins exposure.