Effects of organophosphates on precision-cut kidney slices.

Organophosphate (OP) poisoning, both accidental and with suicidal intent, is a global medical challenge. While the primary toxicity of these pesticides is based on the inhibition of acetylcholinesterase (AChE), case reports describe patients developing OP-mediated renal insufficiency. We set out to investigate possible pathomechanisms utilizing rat precision-cut kidney slices (PCKS). Depending on the method of investigation, PCKS were observed for a maximum of 10 days. PCKS exposed to OP compounds (malaoxon, malathion, paraoxon, parathion) showed a dose-dependent loss of viability and a reduction of total protein content over the course of 10 days. A concentration of 500 µM OP showed the most differences between OP compounds. After two days of incubation parathion showed a significantly lower level of viability than malathion. The respective effects of paraoxon and malaoxon were not significantly different from the control. However, effects of OP were only observed in concentrations exceeding those that were needed to achieve significant AChE inhibition in rat kidney tissue. In addition, we observed histological changes, without inducing LDH leakage. Overall, results suggest that OP exert effects in kidney tissue, that exceed those expected from the sole inhibition of AChE and vary between compounds. Without signs of necrosis, findings call for studies that address other possible pathomechanisms, including inflammatory response, oxidative stress or activation of apoptosis to further understand the nephrotoxicity of OP compounds. Monitoring oxon concentration over time, we demonstrated reduced enzyme-inhibiting properties in the presence of PCKS, suggesting interactions between OP compound and kidney tissue.