Melittin-induced metabolic changes on the Madin-Darby Bovine Kidney cell line

ABSTRACT In this study, the toxic effects of melittin on Madin-Darby Bovine Kidney cells (MDBK) were analyzed with respect to mitochondrial functionality by reduction of MTT and flow cytometry, apoptosis potential, necrosis, oxygen reactive species (ROS) production, lipid peroxidation, and DNA fragmentation using flow cytometry and cell membrane destabilization by confocal microscopy. The toxicity presented dose-dependent characteristics and mitochondrial activity was inhibited by up to 78.24 ±3.59% (P<0.01, n = 6) in MDBK cells exposed to melittin (10μg/mL). Flow cytometry analysis revealed that melittin at 2μg/mL had the highest necrosis rate (P<0.05) for the cells. The lipoperoxidation of the membranes was also higher at 2μg/mL of melittin (P<0.05), which was further confirmed by the microphotographs obtained by confocal microscopy. The highest ROS production occurred when the cells were exposed to 2.5μg/mL melittin (P<0.05), and this concentration also increased DNA fragmentation (P<0.05). There was a significative and positive correlation between the lipoperoxidation of membranes with ROS (R=0.4158), mitochondrial functionality (R=0.4149), and apoptosis (R=0.4978). Thus, the oxidative stress generated by melittin culminates in the elevation of intracellular ROS that initiates a cascade of toxic events in MDBK cells.