Cytotoxic and genotoxic profiles of the pyrethroid insecticide lambda-cyhalothrin and its microformulation Karate® in CHO-K1 cells.

Abstract

Lambda-cyhalothrin (LCT) and its microformulation Karate® (25 % a.i.) were analysed for its genotoxicity and cytotoxicity on Chinese hamster ovary (CHO-K1) cells. Cytokinesis-block micronucleus cytome (CBMN-cyt) and alkaline single-cell gel electrophoresis (SCGE) bioassays were selected to test genotoxicity. Neutral red uptake (NRU), succinic dehydrogenase activity (MTT) and apoptogenic induction were employed for estimating cytotoxicity. Both compounds were analysed within a concentration range of 0.1-100µg/mL. Only LCT produced a significant augment in the frequency of micronuclei (MNs) when the cultures were exposed to highest concentrations of 10 and 100µg LCT/mL. A noticeable decrease in NDI was observed for cultures treated with LCT at 10 and 100µg/mL. Karate® induced the inhibition of both the proportion of viable cells and succinic dehydrogenase activity and triggered apoptosis 24h of exposition. Whilst an increased GDI in CHO-K1 cells was observed in the treatments with 1-100µg Karate®/mL, the GDI was not modified in the treatments employing LCT at equivalent doses. SCGE showed that Karate® was more prone to induce genotoxic effects than LCT. Only 50µg/mL of Karate® was able to increase apoptosis. Our results demonstrate the genomic instability and cytotoxic effects induced by this pyrethroid insecticide, confirming that LCT exposure can result in a severe drawback for the ecological equilibrium of the environment.