Apoptotic responses of Carassius auratus lymphocytes to nodularin exposure in?vitro

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• 作者：Hangjun Zhang ; ^{zhanghangjun@gmail.com} ; Dandan Shao ; Yingzhu Wu ; Chenchen Cai ; Ciming Hu ; Xiaolu Shou ; Bingru Dai ; Binhui Ye ; Mengdi Wang ; Xiuying Jia ; ^{hznujiaxiuying@126.com}
• 关键词：Apoptosis ; Nodularin ; Mitochondrial pathway ; Fish lymphocytes ; ROS
• 刊名：Fish & Shellfish Immunology
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：33
• 期：6
• 页码：1229-1237
• 全文大小：651 K

文摘

Nodularin, a metabolite of Nodularin spumigena, is widely detected in water blooms worldwide and causes serious negative effects on fish. The apoptosis-related cytotoxic effects and mechanisms of nodularin on Carassius auratus lymphocytes were investigated. Transmission electron microscopy results showed that nodularin-treated lymphocytes display a series of morphological changes, including condensed cytoplasm, nuclear chromatin agglutination and marginalization. DNA fragmentation was verified by the DNA-ladder and formation of sub-G1 DNA peaks. These cell characteristics confirmed the occurrence of apoptosis in lymphocytes. Flow cytometric results showed that the percentages of apoptotic cells incubated with 1, 5, 10, and 100?¦Ìg/L nodularin for 12?h reached 15.76 % , 17.36 % , 20.34 % and 44.21 % , respectively; controls showed low rates of apoptosis (2.4 % ). The mechanism of apoptosis induced by nodularin was determined, and results showed that nodularin exposure caused a significant increase in intracellular reactive oxygen species (ROS), loss of mitochondrial transmembrane potential in a dose-dependent manner, upregulation of intracellular Ca²⁺, downregulation of Bcl-2 and upregulation of Bax expression at the mRNA and protein levels, and activation of caspase-3 and caspase-9 without caspase-8. In summary, all the results suggest that nodularin induces lymphocyte apoptosis via the mitochondrial apoptotic pathway and destroys the immune response of fish.