Role of eicosanoids in gastric mucosal protection and damage

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Aim: Microtubular system plays an important role in cell structure and functions including intracellular transport, cell division, movement, and differentiation. The aims of this study were to assess effects of colchicine (CC; drug which inhibits microtubular formation) on ethanol injury and Ca^<2+>-fluxes in cultured rat gastric cells. Methods: Gastric cells were isolated from male Wistar rats and cultured according to Terano's method. 1) Dose- and time-dependency of cell injury by ethanol were assessed with ^<51>Cr-release. 2) To assess effect of CC on cell injury, the cells were pre-incubated in oxygenated medium alone or medium containing 10^<-7>-10^<-5> in oxygenated medium alone or medium containing 10^<-7>-10^<-5> M CC for 30 min at 37ﾟC in the absence or presence of Ca^<2+>. Then cells were incubated with 8% ethanol for 60 min and ^<51>Cr-release was measured. 3) ^<45>Ca^<2+>-influx was assessed in the cells pre-incubated with medium alone or medium containing CC for 30 min. 4) Ca^<2+>-efflux was measured by incubating the pre-labeled cells with ^<45>CaCl_2 in medium alone or medium containing CC for 30 min. Results: Ethanol caused cell injury in dose- and time- related ways. So, 60-min exposure to 80% ethanol was chosen to induce cell injury in the following experiments. Cc alone did not affect ^<51>Cr-release, but increased ethanol injury at the concentration of 10^<-5> M. This effect was seen only in Ca^<2+>-containing medium (Table). CC did not affect Ca^<2+>-influx but reduced Ca^<2+>-efflux.Specific ^<51>Cr-release (%) Ca^<2+> conc. in medium n Ca-free 1.3 mM 3.9 mM Saline + 8% ethanol 6 11 * 2 27 * 4 29 * 3 CC + 8% etanol 6 13 * 4 38 * 4 48 * 6 P-value NS < 0.01 < 0.01 Conclusion: Microtubules may modulate Ca^<2+>-efflux from cultured rat gastric cells. Ethanol injury to the cells is aggravated by impairment of microtubules with CC possibly via decrease in Ca^<2+>-efflux, and resultant increase in cytosolic free calcium.