Experimental intraperitoneal infusion of OK-432 in rats: Evaluation of peritoneal complications and pathology

Purpose: OK-432 is known to be a potent sclerosant of cystic lesions. The purpose of this study was to evaluate both its safety and pathologic effects after the infusion of OK-432 into the peritoneal cavity of rats. Materials and methods: Twenty male rats were used in this study. Twelve rats were infused intraperitoneally with 0.2 Klinishe Einheit of OK-432 melted in 2 mL of normal saline (group 1: the treated group); four rats each were infused intraperitoneally with 0.5 mL of 99% ethanol (group 2) and normal saline (group 3), and served as the control groups. An abdominal ultrasonographic examination was performed both before and after the infusions in all rats. Three rats in group 1 and one rat in each of groups 2 and 3 were sacrificed each week following the infusion. Gross and microscopic evaluations of the peritoneum and abdominal cavity were performed on each rat. Results: In group 1, the abdomen was clear on gross inspection and the peritoneum was unremarkable on microscopic examination. In group 2, mild-to-moderate peritoneal adhesions were revealed grossly, and inflammation and fibrosis of the peritoneum were demonstrated microscopically. In group 3, no specific abnormalities were noted on gross or microscopic examinations. Conclusion: Leakage or abnormal infusion of OK-432 solution into the peritoneal cavity during sclerotherapy of intra-abdominal or retroperitoneal cystic lesions does not result in any significant complications.