Effects of deltamethrin on functions of rat liver mitochondria and on native and synthetic model membranes

• Published in: Toxicology letters Vol. 152; no. 3; pp. 191 - 202
• Main Authors: Braguini, Welligton L., Cadena, Silvia M.S.C., Carnieri, Eva G.S., Rocha, Maria Eliane M., de Oliveira, Maria Benigna M.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 25-09-2004; Amsterdam Elsevier Science
• Subjects: Animals; Biological and medical sciences; Cell structures and functions; Deltamethrin; Electron Transport; Fundamental and applied biological sciences. Psychology; General aspects. Methods; Insecticides - toxicity; Lipid Metabolism; Liposomes; Male; Medical sciences; Membranes, Artificial; Mitochondria; Mitochondria and cell respiration; Mitochondria, Liver - drug effects; Mitochondria, Liver - physiology; Molecular and cellular biology; Nitriles; Oxygen Consumption; Pyrethrins - toxicity; Pyrethroid insecticides; Rats; Rats, Wistar; Respiratory chain enzymes; Swelling; Temperature; Toxicology; Pyrethroid insecticides; Respiratory chain enzymes; Mitochondria; Liposomes; Swelling; Deltamethrin; Insecticide; Rat; Enzyme; Liver; Pesticides; Rodentia; Liposome; Pyrethroids; Drug carrier; Tissue; Vertebrata; Respiratory chain; Mammalia; Animal; Membrane; Models; Cell respiration
• ISSN: 0378-4274; 1879-3169
• DOI: 10.1016/j.toxlet.2004.03.017

Deltamethrin (DTM) is a synthetic pyrethroid insecticide used wideworld in agriculture, home pest control, protection of foodstuff, and disease vector control. It has widespread applications in Brazilian agriculture. The effects of DTM on mitochondrial respiratory parameters and on the organization of artificial and native membranes are described. DTM (200
nmol
mg
−1 protein) on isolated liver mitochondria decreased oxygen consumption of both, state III and state IV, as well as the inner mitochondrial membrane potential (Δ
ψ). Analysis of segments of the respiratory chain suggested that the DTM inhibition site is located between complex II and complex III. Mitochondrial swelling, energized or driven by the K
+ diffusion potential using valinomycin, were partially inhibited by DTM (200
nmol
mg
−1 protein). Fluorescence polarization of DPH and DPH-PA, probing the core and outer regions, respectively, of dimyristoylphosphatidylcholine (DMPC) and native mitochondrial membranes, indicated that DTM shifts the midpoint phase transition to lower values, besides broadening the phase transition. DTM decreased the lipid order of DMPC bilayers, at temperatures lower than the transition temperature and also caused a disordering effect on native membranes. However at temperatures above the transition temperature, the pesticide increased the rigidity of the membrane. These results suggest that DTM causes perturbations in lipid-lipid and lipid-protein interactions, interferes in transport mechanisms operating at the membrane level, and causes alterations of membrane permeability and mitochondrial enzyme activities. These effects could be associated with the toxicity of deltamethrin.