AN INVITRO SYSTEM TO SCREEN FOR DIARRHEAGENIC CHEMICALS

We examined an in vitro system to screen for diarrheagenic chemicals u sing an established intestinal cell line (T84 human colonic carcinoma) . The cells were grown on Millicell-PCF (polycarbonate membrane) wells . The cells were seeded at approximately 5 x 10(6) cells/30mm well and incubated for 9-11 days in a 5% CO2 incubator saturated with water at 37-degrees-C. The culture medium was a 1:1 mixture of Ham's F12 and D ulbecco's MEM with 5% fetal bovine serum and 25 mug/ml gentamicin sulf ate. The well containing cells was removed from the incubator and moun ted in a modified Ussing chamber for measurement of short-circuit curr ent (I(SC)). Chemical-induced increases in I(SC) usually indicative of electrogenic epithelial Cl- secretion, which is associated with diarr heagenic effects in animals and humans. T84 cells grown on Millicell-P CF membrane responded with an increase in I(SC) after basolateral addi tion of the cholinergic (muscarinic) agonist carbachol, prostaglandin E2, 16,16-dimethylprostaglandin E2, and forskolin, while non-diarrheag enic prostaglandin D2 did not affect Based on our results, this in vit ro system has the potential to be adapted as a rapid screen for detect ing diarrheagenic chemicals.