Λ-cyhalothrin causes oxidative stress accompanied by reduced glutathione alteration and modulation of regulatory protein p53 expression in the fish brain

Abstract

The synthetic pyrethroid of systemic insecticidal and acaricidal action, λ-cyhalothrin, is characterized by typical axonal excitotoxicity. Currently, it is widely used in agriculture worldwide. In fish, it negatively affects the functional characteristics of the nervous system, causes motorial paralysis, and increases mortality. The concentrations of λ-cyhalothrin for the experiment were determined at a rate of 5% and 10% of LC50, which are 271 ng/L and 542 ng/L, respectively. Λ-cyhalothrin causes oxidative damage in the brain cells of the rainbow trout and, probably, irreversible disturbances in brain cells. The content of reduced glutathione in the fish brain treated by low doses of λ-cyhalothrin was significantly lower than in the control fish. It may indicate the breakdown of this part of antioxidant protection. One of the universal and multifunctional regulatory proteins, which plays a vital role in most cell types is the p53 protein that supports cell viability through a wide range of signalling pathways. Changes in the p53 protein expression are determined in fish of all experimental groups. Moreover, less significant suppression of its expression is found in fish that have been treated by a dose of 5% LC for 28 days. Unlike the 5% LC50, the dose of 10% LC50 induces a critical decrease in the p53 protein content after both 4 and 28 days of insecticide exposure. Detected changes in the reduced glutathione content and p53 protein expression in the fish brain are associated with the oxidative stress generation caused by low sublethal doses of λ-cyhalothrin. A significant decrease in the p53 protein content in the fish brain under the impact of the low doses of the synthetic pyrethroid can indicate irreversible disturbance of this protein functioning. The inhibition of protein p53 expression may be an adequate biomarker of the nervous cell adaptation to the toxic effect of synthetic pyrethroids in the fish brain.