Improved in vitro method for screening organophosphate-induced delayed polyneuropathy

Organophosphate-induced delayed polyneuropathy (OPIDP) has been tested mainly byin vivo methods in the chicken and by examination of the inhibition of neuropathy target esterase in their neuronal tissue. An alternative method, using permanent neuronal cell lines and detecting the growth of neurite-like sprouts by morphometric means, has meanwhile been validated to substitute thesein vivo investigations, at least in part. This paper reports some modifications of this in vitro method in order to optimize it for a routine laboratory screening test of organophosphates. By determination of cytoskeletal elements with cell ELISA, it was demonstrated that seven OPIDP-inducing compounds [tri-o-cresyl phosphate (TOCP) and its metabolite cresyl-saligeninphosphate, haloxon, mipafox, leptophos, EPN and chlorpyrifos] and nine negative control substances [paraoxon, methylazinphos, ethylazinphos, dimefox, dimethoate, phenylmethanesulfonylfluoride (PMSF) and three organophosphate metabolite-cresol, phenol and p-nitrophenol] resulted in the same effects as seen in the original test method. The cell ELISA technique thus represents an alternative method that is much easier to perform than the morphometric method.