Neurotoxicological evaluation of microcystin-LR exposure at environmental relevant concentrations on nematode Caenorhabditis elegans

• Published in: Environmental science and pollution research international 2013-03, Vol.20 (3), p.1823-1830
• Main Authors: Ju, Jingjuan, Ruan, Qinli, Li, Xiaobo, Liu, Ran, Li, Yunhui, Pu, Yuepu, Yin, Lihong, Wang, Dayong
• Format: Article
• Language: English
• Subjects: Animals; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Caenorhabditis elegans; Caenorhabditis elegans - drug effects; Cholinergic Neurons - drug effects; Cholinergic Neurons - metabolism; Dopamine receptors; Dopaminergic Neurons - drug effects; Dopaminergic Neurons - metabolism; Dose-Response Relationship, Drug; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Exposure; GABAergic Neurons - drug effects; GABAergic Neurons - metabolism; Gene Expression - drug effects; Gene frequency; Genetic engineering; Glutamatergic transmission; Labeling; Larvae; Locomotion - drug effects; Marine Toxins - toxicity; Microcystin-LR; Microcystins; Microcystins - toxicity; Nematoda; Nematodes; Nervous system; Nervous System - drug effects; Nervous System - metabolism; Neurons; Neurotoxicity; Real-Time Polymerase Chain Reaction; Research Article; Serotonergic Neurons - drug effects; Serotonergic Neurons - metabolism; Serotonin; Side effects; Studies; Waste Water Technology; Water Management; Water Pollution Control; Worms; γ-Aminobutyric acid
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-012-1151-2

Previous studies have not examined the adverse effects of microcystin-LR (MC-LR) at environmental relevant concentrations on the development and functions of nervous system. The neurotoxic effects of MC-LR exposure on neurotransmitter systems were investigated in Caenorhabditis elegans . After exposing L1 larvae to 0.1, 1, 10, and 100 μg l −1 of MC-LR for 8 and 24 h, the adverse effects on GABAergic, cholinergic, serotonergic, dopaminergic, and glutamatergic neurons were examined. The expression levels of genes required for development and functions of GABAergic neurons were further investigated. Body bend frequency and head thrash frequency decreased significantly after MC-LR exposure for 8 h at concentrations more than 1 μg l −1 and after MC-LR exposure for 24 h at concentrations more than 0.1 μg l −1 . Loss of GABAergic neurons increased significantly in a dose-dependent manner after MC-LR exposure at concentrations more than 0.1 μg l −1 . In contrast, no obvious neuronal losses or morphologic changes were observed in cholinergic, serotonergic, dopaminergic, and glutamatergic neurons in MC-LR-exposed nematodes. Quantitative real-time PCR assay further showed that expression levels of unc-30 , unc-46 , unc-47 , and exp-1 genes required for development and function of GABAergic neurons decreased significantly in nematodes exposed to MC-LR at concentrations more than 0.1 or 1 μg l −1 . MC-LR at environmental relevant concentrations caused neurobehavioral defects, which may be largely due to the neuronal loss and the alterations of expression level of genes required for GABAergic neurotransmitter system in C. elegans.