This study aimed to investigate the toxic effects of microcystin-LR (MC-LR), which is released from several bloom-forming cyanobacteria, on the glucose metabolism of pancreatic β cells in vivo and in vitro. Male mice and the pancreatic MIN6 cells were respectively treated with varying concentrations of MC-LR. After 3- or 6- months of MC-LR exposure, increase in the body weight of mice was found to be inhibited, and the structure of their pancreatic tissues was damaged with impaired glucose tolerance and impaired insulin secretion. Further, these toxic effects became more pronounced with time and with increased dosages. Direct cytotoxic effects of MC-LR were observed in the MIN6 pancreatic β-cells possibly due to their expression of the MC-LR specific transporter. MC-LR entered the MIN6 cells that significantly reduced the cell viability. Both in vivo and in vitro experiments demonstrated that MC-LR was able to induce apoptosis, possibly associated with mitochondrial damage. Above all, these findings implied that MC-LR may be transported into the pancreatic β cells and cause subsequent cytotoxicity.

中文翻译：

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微囊藻毒素-LR 在体内和体外损害胰腺 β 细胞的葡萄糖代谢

本研究旨在研究从几种藻华形成蓝藻中释放的微囊藻毒素-LR (MC-LR) 对体内和体外胰腺 β 细胞葡萄糖代谢的毒性作用。雄性小鼠和胰腺 MIN6 细胞分别用不同浓度的 MC-LR 处理。MC-LR 暴露 3 或 6 个月后，发现小鼠体重增加受到抑制，胰腺组织结构受损，糖耐量受损和胰岛素分泌受损。此外，随着时间的推移和剂量的增加，这些毒性作用变得更加明显。在 MIN6 胰腺 β 细胞中观察到 MC-LR 的直接细胞毒性作用，这可能是由于它们表达了 MC-LR 特异性转运蛋白。MC-LR 进入 MIN6 细胞，显着降低细胞活力。体内和体外实验均表明 MC-LR 能够诱导细胞凋亡，这可能与线粒体损伤有关。最重要的是，这些发现暗示 MC-LR 可能被转运到胰腺 β 细胞中并引起随后的细胞毒性。