title: Environmental Presence of Hexavalent but Not Trivalent Chromium Causes Neurotoxicity in Exposed Drosophila melanogaster.
abstract: A number of environmental chemicals are known to cause neurotoxicity to exposed organisms. Chromium (Cr), one of the major elements in earth's crust, is a priority environmental chemical depending on its valence state, and limited information is available on its neurotoxic potential. We, therefore, explored the neurotoxic potential of environmentally present trivalent- (Cr(III)) and hexavalent-Cr (Cr(VI)) on tested brain cell types in a genetically tractable organism Drosophila melanogaster along with its organismal response. Third instar larvae of w1118were fed environmentally relevant concentrations (5.0-20.0 μg/ml) of Cr(III)- or Cr(VI)-salt-mixed food for 24 and 48 h, and their exposure effects were examined in different brain cells of exposed organism. A significant reduction in the number of neuronal cells was observed in organism that were fed Cr(VI)- but not Cr(III)-salt-mixed food. Interestingly, glial cells were not affected by Cr(III) or Cr(VI) exposure. The tested cholinergic and dopaminergic neuronal cells were affected by Cr(VI) only with the later by 20.0 μg/ml Cr(VI) exposure after 48 h. The locomotor activity was significantly affected by Cr(VI) in exposed organism. Concomitantly, a significant increase in the level of reactive oxygen species (ROS) coupled with increased oxidative stress led to apoptotic cell death in the tested brain cells of Cr(VI)-exposed Drosophila, which were reversed by vitamin C supplementation. Conclusively, the present study provides evidence of environmental Cr(VI)-induced adversities on the brain of exposed Drosophila along with behavioral deficit which would likely to have relevance in humans and recommends Drosophila as a model for neurotoxicity.
authors.affiliation: Embryotoxicology Laboratory, Environmental Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow, 226 001, Uttar Pradesh, India.|Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR Campus, Lucknow, India.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Singh
authors.affiliation: Embryotoxicology Laboratory, Environmental Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow, 226 001, Uttar Pradesh, India. dkchowdhuri@iitr.res.in.|Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR Campus, Lucknow, India. dkchowdhuri@iitr.res.in.
authors.forename: D Kar
authors.initials: DK
authors.lastname: Chowdhuri
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D002857:Chromium / Q000633:toxicity*; D059290:Dopaminergic Neurons / Q000187:drug effects / Q000378:metabolism; D004331:Drosophila melanogaster / Q000187:drug effects / Q000502:physiology*; D004785:Environmental Pollutants / Q000633:toxicity*; D017952:Ganglia, Invertebrate / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008954:Models, Biological; D009043:Motor Activity / Q000187:drug effects; D009498:Neurotoxins / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D010447:Peptide Hydrolases / Q000378:metabolism; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D015415:Biomarkers; D002800:Cholinesterase Inhibitors; D004785:Environmental Pollutants; D009498:Neurotoxins; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D002857:Chromium; C074702:chromium hexavalent ion; D000110:Acetylcholinesterase; D010447:Peptide Hydrolases; C108711:DEVDase
keywords: Cholinergic neurons; Dopaminergic neurons; Drosophila; Hexavalent chromium; Locomotor activity; Oxidative stress