Cypermethrin-Induces Oxidative Stress to the Freshwater Ciliate Model: Paramecium tetraurelia

Abstract

Synthetic Pyrethroids are considered to be safe over other insecticides; however, data indicate that their use may pose risk to environmental biota, especially, aquatic organisms. Therefore, the aim of the present study was to investigate the effect of cypermethrin, a widely used insecticide and one of the most common contaminants in freshwater aquatic system on the oxidative stress biomarkers of the freshwater ciliate Paramecium tetraurelia. After the treatment of paramecium cells with increasing concentrations of cypermethrin (0.05, 0.5,1, 2μg/l), we followed up the growth kinetics, generation time and the response percentage. Also, we studied the variation in biomarkers of stress such as: Proteins, GSH content, GST and CAT activities. Our results showed a significant decrease in the proliferation of cell, we denote a difference of nearly 1,900 cells between the control cells and those treated with (2μg/l) at the fourth day of treatment. This finding is correlated by the decrease in generation number and velocity and the increase in generation time. Also, we noted an inhibition in the response percentage: It varies from (20%) to (54%) for 0.5μg/l and 2μg/l respectively. The rate of total proteins increased in dose dependent manner and very highly significant for the tow highest concentrations (1 and 2μg/l). The monitoring of biomarkers revealed a depletion in GSH content in a proportional and dose dependent manner (it is 7.34188758μmol/mg Pro for the control whereas it is 2.41682134μmol/mg Pro for 2μg/l ) accompanied by an increase in the GST activity (we note an increase of the order of 1.62932472μM/min/mg Pro for the highest concentration compared to the control which is of the order of 0.59883133μM/min/mg Pro) .In parallel, a strong induction of the CAT activity was noted specially for the highest dose.