Determination of oxidative stress potantial of lambda-cyhalothrin in the presence of pbo and its effects on stress proteins and apoptosis in the liver of oreochromis niloticus

The aim of the present study was to investigate the effects of ?-cyano synthetic pyrethroid insecticide and acaricide lambda-cyhalothrin in the presence of PBO, a modulator of cytochrome P450, on glutathione redox status and GSH-related enzymes activities, lipid peroxidation, stress proteins and apoptosis in the liver of Oreochromis niloticus. For this aim, fish were placed in 0.48 µg/L lambda-cyhalothrin and 0.01 mg/L PBO containing water for 96-h and 15-d. tGSH, GSH, GSSG and TBARS contents, GSH/GSSG ratio, GPx, GR, GST and caspase-3 enzymes activities were determined spectrophotometrically, while HSP70 content was measured by ELISA test technique.It was shown that acute treatment of lambda-cyhalothrin causes an increase in TBARS contents while tGSH and GSH contents and GST enzyme activity were increased to block lipid peroxidation in subacute effect. Beside an elevation in GPx enzyme activity and HSP70, TBARS contents in subacute effect; tGSH, GSH contents and GST enzyme activity were increased in both acute and subacute effects of lambda-cyhalothrin+PBO treatment. A relationship was observed between reduced caspase-3 and increased GST activities in acute treatment.Results of the present study revealed that lambda-cyhalothrin causes oxidative stress in the applied concentration and increases in GSH and GSH-related enzymes supply an adaptation to its oxidative effects. PBO synergistically modulates the oxidative stress potential of lambda-cyhalothrin. HSP70 induction could be an adaptive response to oxidative stress caused by lambda-cyhalothrin+PBO treatment. It was shown that inhibition of caspase-3 activity is related to the induced GST enzyme activity. Induced GST enzyme activity suggested an adaptive response against oxidative stress induced by lambda-cyhalothrin treatment, rather than a conjugation reaction with GSH for detoxicification.