Toluene and p-xylene induced LLC-PK1 apoptosis.

Occupational exposure to organic solvents was found to be associated with development and progression of tubulo-interstitial fibrosis and chronic renal failure. However, the cellular mechanism by which this occurs remains elusive. This study was conducted to evaluate the mode of cell death in proximal tubular cells exposed to organic solvents. LLC-PK1 cell line cytotoxicity due to exposure to 1 mM of either p-xylene or toluene was compared to untreated control by cell viability, LDH release, and DNA fragmentation. Cells were exposed to solvents for 96 hrs. Toluene and p-xylene reduced cell viability and increased DNA fragmentation. LDH release was unchanged. These data indicates that long-term exposure to organic solvents is associated with proximal tubule cell apoptosis, which may be the mechanism of progressive renal fibrosis and renal failure in patients with high solvent exposure.