title: Potential of casein as a nutrient intervention to alleviate lead (Pb) acetate-mediated oxidative stress and neurotoxicity: First evidence in Drosophila melanogaster.
abstract: Understanding the interaction between dietary protein deficits and neurotoxicants such as lead (Pb) is critical since oxidative stress is a common denominator under such conditions. The Drosophila system is an extensively used model to investigate the interaction between nutrients and environmental toxicants. Accordingly, we have examined the hypothesis that casein (CSN) enrichment has the propensity to attenuate Pb-associated phenotype, oxidative stress and neurotoxicity in Drosophila melanogaster. Exposure of young (2-3 d) and adult flies (10-12 d old) to Pb acetate (0-20 mM, 7 d) in the medium resulted in a concentration dependent mortality and the survivors exhibited a hyperactive phenotype. While males showed higher susceptibility to Pb among both age groups, young flies were relatively more susceptible than adults. Pb exposure (5-10 mM, 5 d) among young flies caused robust oxidative stress as evidenced by markedly elevated levels of reactive oxygen species with concomitant perturbations in the activities of antioxidant enzymes (diminished SOD and elevated thioredoxin reductase) and altered redox state. Further, Pb caused significant elevation in the activity of acetylcholinesterase and dopamine levels. In a satellite study, we assessed the modulatory effect of CSN-enriched diet (1-2%) on Pb intoxication in terms of lethality, hyperactivity, oxidative stress and neurotoxicity. CSN markedly offset Pb-induced lethality and diminished the hyperactivity response. While CSN enrichment among Pb (5 mM) treated flies caused further elevation in ROS levels and thioredoxin reductase activity, the SOD levels were restored to normalcy. Further, CSN improved the activity levels of complex I-III and restored the dopamine levels. Our data suggest that Pb-induced toxicity in the Drosophila system may be predominantly mediated through oxidative stress mechanisms and the propensity of casein-enriched diet to abrogate such responses. Hence, we propose that enrichment of diet with protein such as casein may be a useful approach to alleviate Pb associated adverse effects in children.
authors.affiliation: Department of Biochemistry and Nutrition, CSIR-Central Food Technological Research Institute (CFTRI), Mysore 570020, India.
authors.forename: Lalith Kumar
authors.initials: LK
authors.lastname: Venkareddy
authors.affiliation: Department of Biochemistry and Nutrition, CSIR-Central Food Technological Research Institute (CFTRI), Mysore 570020, India. Electronic address: mura16@yahoo.com.
authors.lastname: Muralidhara
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D002364:Caseins / Q000008:administration & dosage*; D004032:Diet; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004331:Drosophila melanogaster / Q000187:drug effects* / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism; D005260:Female; D005426:Flight, Animal / Q000187:drug effects; D020263:Lead Poisoning, Nervous System / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009420:Nervous System / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009942:Organometallic Compounds / Q000633:toxicity*; D018384:Oxidative Stress; D012737:Sex Factors; D013997:Time Factors
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D002364:Caseins; D004798:Enzymes; D009942:Organometallic Compounds; D000110:Acetylcholinesterase; C008261:lead acetate; D004298:Dopamine
keywords: Casein; Drosophila; Lead acetate; Neurotoxicity; Oxidative stress