Cytotoxic effects of Helicobacter pylori on guinea pig gastric glands.

To study the cytotoxic effect of Helicobacter pylori on the gastric P3cosa, gastric glands harvested from guinea pigs were incubated with clinical isolates of H. pylori. H. pylori alone (H group), urea alone (U group), H. pylori plus urea (HU group), and H. pylori plus urea and the urease inhibitor acetohydroxamic acid (HUA group) were incubated with isolated gastric glands. The controls were incubated without additives. Incubation was for 30, 60 and 180 min at 37 degrees C in a microaerophilic atmosphere. The HU group showed an increase in the ammonia concentration and pH of the culture supernatant; release of lactate dehydrogenase (LDH) and glutamic oxaloacetic transaminase (GOT) into the supernatant owing to cell disruption was also increased. In the HUA group, since urease activity was inhibited, the ammonia concentration and pH were also significantly lower (p < 0.001), and LDH and GOT release into the supernatant was significantly reduced (p < 0.001-0.01). Observation by light and electron microscopy showed clear intracellular vacuolization of the gastric glands and adherence of H. pylori to the cell surfaces. These results suggest that ammonia, a metabolite of urea released by H. pylori urease, is one of the important factors in cytotoxicity in isolated gastric glands.