Evaluation of Four Herbicides Cytotoxicity on Normal Liver THLE2 Cells

Abstract

THE widespread increase in pesticide use is a source of pollution worldwide. Although herbicides have various applications, they nonetheless represent a risk to human health due to their tendency to bioaccumulate in many different environments. The purpose of this research was to investigate the cytotoxic effects of pendimethalin (PEN), oxyfluorfen (OFN), fluazifop-p-butyl (FPB), and pyraflufen ethyl (PFE) herbicides on human normal liver (THLE2) cells through the evaluation of the cell viability (using the MTT assay), apoptosis (using qPCR), cell cycle (using flowcytometry), and oxidative stress status (using biochemical assays). The four herbicides induced cytotoxic effects on THLE2 cells as evidenced by suppressed cell viability with IC50 values as follows: PEN (60.50±3.19 μM), OFN (100.36±4.66 μM), FPB (174.90±6.54 μM) and PFE (186.72±6.82 μM). They also increased apoptosis (high Bax and caspase 3, and low Bcl2 gene expression). However, only PEN and OFN induced cell cycle arrest in G0/G1 and both S and G2/M phases, respectively, with subsequent downregulated expression of cyclin D1, cyclin A2, and cyclin-dependent kinase 4 (CDK4). Among the four herbicides, only OFN, PFE, and FPB induced oxidative stress damage as revealed by higher levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), inhibited activities of antioxidant enzymes [catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx)], and downregulated expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) genes. FPB and PFE had a greater safety margin on human normal THLE2 cells and might be used with less adverse consequences on human and animal health.