Submitted to: Toxic Substances Technical Meeting Proceedings
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/21/1996
Publication Date: N/A
Citation: Interpretive Summary: Laser cytometry is a new, non-invasive method of monitoring specific functions in living cells and how these functions are changed by natural products such as hormones or by poisonous substances. This report is the first study using this technology to compare the effect of an insecticide on living insect and vertebrate cell lines. Using this technology, we were able to show that certain insect cells suffer more when exposed to the insecticide, permethrin, than do cells from mammals. This study shows that laser cytometry provides an extremely sensitive means of evaluating the toxic effects of a pesticide on specific types of cells. Laser cytometry also provides an alternative to the use of live animals to analyze the effects of not only known poisons but also of new pesticides and drugs that are currently being developed.
Technical Abstract: Insect epithelial cell lines derived from Anopheles gambiae and Aedes albopictus mosquito larvae, and a clonal rat liver cell line (Clone 9) were exposed to the synthetic pyrethroid insecticide, permethrin. In this study, endpoints of cellular injury in epithelial cell lines were evaluated by laser cytometry. Kinetic analyses of intracellular glutathione (GSH) and Ca**2+ content ([Ca**2+]i), reactive oxygen species (ROS) production, mitochondrial (MMP) and plasma membrane potentials (PMP), intracellular pH, and gap junctional intercellular communication (GJIC) were performed. Cells derived from A. gambiae and A. albopictus exhibited IC50 values of 15 nM and 300 nM respectively after 72 h of exposure to permethrin. The rat Clone 9 cells did not show any growth inhibition when treated with permethrin even at the highest concentration used (10 uM). A. gambiae cells treated at the IC50 concentration for 1 h at room temperature exhibited changes only in the PMP values, indicating toxin-induced sustained depolarization. However, when A. albopictus cells were treated with permethrin at the IC50 and Clone 9 cells at a concentration of 1.0 uM for 1 h, similar changes were observed in ROS, MMP and GSH levels. These studies identifed possible cellular targets of injury in nonexcitable epithelial cells caused by exposure to permethrin and reveal that insect epithelial cells are much more sensitive to this toxin than mammalian epithelial cells. This is the first report directly comparing effects of a cytotoxin on insect and mammalian cells, and illustrates the potential that laser cytometry offers as a direct and rapid method of analyzing the effects of pesticides on specific living cell lines rather than on living animals.