Li Xiao-Bo, Zhang Xin, Ju Jingjuan, Li Yunhui, Yin Lihong, Pu Yuepu
Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Dingjiaqiao 87, Nanjing, 210009, China,
Environ Sci Pollut Res Int. 2014 Nov;21(21):12419-25. doi: 10.1007/s11356-014-3151-x. Epub 2014 Jun 18.
Microcystin-LR (MC-LR) is a widely studied toxic peptide secreted by certain water blooms of cyanobacteria that exhibit hepatotoxicity and neural toxicity. This study aimed to observe the neurotoxic effects of low-dose MC-LR exposure by oral administration. Male Sprague-Dawley (SD) rats were administered orally every 2 days for 8 weeks with pure water and 0.2, 1.0, and 5.0 μg/kg MC-LR. The Morris water maze test was used to assess the spatial learning and memory capability of rats. The activation of astrocytes and nitric oxide synthase (NOS) was evaluated by immunohistochemistry, and concentrations of nitric oxide (NO) in rat hippocampus were analyzed. Slight liver dysfunction was observed in the 5.0 μg/kg MC-LR-treated rats. Impairment of spatial learning and memory was also observed in the 5.0 μg/kg MC-LR-treated rats. Astrocytes in the hippocampus of the 5.0 μg/kg MC-LR-treated rats showed enhanced activation and cell density; the inflammatory indicators, NOS and NO, increased in accordance with astrocyte activation. This study showed that oral exposure of MC-LR had adverse affects on neurobehaviors, and induced inflammation in memory-related brain regions.
微囊藻毒素-LR（MC-LR）是一种广泛研究的有毒肽，由某些蓝藻水华分泌，具有肝毒性和神经毒性。本研究旨在观察口服低剂量MC-LR的神经毒性作用。将雄性Sprague-Dawley（SD）大鼠每2天口服给予纯净水以及0.2、1.0和5.0μg/kg的MC-LR，持续8周。采用莫里斯水迷宫试验评估大鼠的空间学习和记忆能力。通过免疫组织化学评估星形胶质细胞和一氧化氮合酶（NOS）的激活情况，并分析大鼠海马体中一氧化氮（NO）的浓度。在接受5.0μg/kg MC-LR处理的大鼠中观察到轻微肝功能障碍。在接受5.0μg/kg MC-LR处理的大鼠中也观察到空间学习和记忆受损。接受5.0μg/kg MC-LR处理的大鼠海马体中的星形胶质细胞显示出增强的激活和细胞密度；炎症指标NOS和NO随着星形胶质细胞的激活而增加。本研究表明，口服MC-LR对神经行为有不良影响，并在与记忆相关的脑区诱发炎症。
