title: Effects of type II pyrethroid cyhalothrin on rat innate immunity: a flow cytometric study.
abstract: Synthetic type II pyrethroids induce anxiety, immunosuppression or, alternatively, immunostimulatory effects in laboratory animals. Macrophages and neutrophils are known to be key elements in cellular immune responses. The present study was designed to investigate the in vivo effects of cyhalothrin (1.0 and 3.0 mg/kg/once daily for 7 days) on macrophage and neutrophil activities, using a flow cytometry method. Results showed that cyhalothrin treatment decreased the percentage and intensity of phagocytosis performed by macrophages, but did not alter these parameters in neutrophils; and also decreased basal neutrophil oxidative burst and increased S. aureus-induced neutrophil oxidative burst, but did not alter these responses in macrophages. The present results are discussed in the light of a possible indirect action of cyhalothrin on macrophage and neutrophil activities via hypothalamic pituitary adrenal (HPA) axis activation. A possible direct effect of cyhalothrin on macrophage and neutrophil activities is also considered.
authors.affiliation: Molecular Pharmacology Laboratory, Department of Pharmaceutical Sciences, School of Health Sciences, University of Brasilia, Brasília, DF, Brazil. dario@unb.br
authors.forename: D A
authors.initials: DA
authors.lastname: Righi
authors.forename: F G
authors.initials: FG
authors.lastname: Xavier
authors.forename: J
authors.initials: J
authors.lastname: Palermo-Neto
mesh_terms: D000818:Animals; D005434:Flow Cytometry; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000276:immunology; D007113:Immunity, Innate / Q000187:drug effects*; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D007306:Insecticides / Q000633:toxicity*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology; D008297:Male; D009163:Mycobacterium bovis / Q000276:immunology; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology; D009570:Nitriles / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects; D011722:Pyrethrins / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D016897:Respiratory Burst / Q000187:drug effects
chemical_list: D007202:Indicators and Reagents; D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C037304:cyhalothrin