FIG. 1.

Effect of clodronate treatment on Helicobacter pylori-induced gastritis. (A) Mongolian gerbils were inoculated with H. pylori, and after 12 weeks, PBS or clodronate liposomes (4 ml/kg body weight) were injected intravenously. After 7 days, the gerbils were killed; their stomachs were removed, fixed, and stained with H&E (middle and right panels). Left panel shows uninfected control. Original magnification, ×100. (B) Gerbils were treated as described above. Paraffin-embedded stomach sections were prepared after PBS or clodronate injection and were immunostained for F4/80 (middle and right panel). Left panel shows stomach section of uninfected control. Original magnification, ×100. (C) Clodronate or PBS liposomes were injected intravenously into Mongolian gerbils. After 48 h, systemic inflammation was induced by intraperitoneal injection of LPS (5 mg/kg body weight). Ten hours later, the gerbils were killed; F4/80 expression in the colon, liver, and spleen was determined by immunohistochemistry. (D) Schematic representation of the experimental protocol for in vivo depletion of macrophages by clodronate. Gerbils were inoculated with H. pylori, and after 12 weeks (w), PBS or clodronate liposomes (4 ml/kg body weight) were injected intravenously. After 7 days, the gerbils were killed and their stomachs analyzed. (E) Numbers of F4/80-positive cells were compared for gerbils treated with PBS or clodronate as described above. (F) Inflammatory cell infiltration was evaluated by the updated Sydney system. The results shown in panels E and F are the means ± SEM. **, P < 0.05 by Student's t test.