EFFECT OF POVIDONE-IODINE LAVAGE ON PERITONEAL DEFENSE-MECHANISMS IN RATS

Objective: To assess the effect of povidone iodine lavage on peritonea l defence mechanisms in rats. Design: Randomised study. Material: 90 W istar albino rats. Interventions: Rats were divided in three groups of 30. All rats underwent midline laparotomy, and 20 rats in each group had peritoneal lavage with 20 ml 1% povidone iodine, samples being tak en before lavage in 10 and after lavage in 10. Main outcome measures: Effect of povidone-iodine lavage compared with laparotomy alone on bac tericidal activity of peritoneal fluid (group 1); chemotactic indices of polymorphonuclear leucocytes (PMNL) (group 2); and total cell count s, cell types, and peritoneal phagocytic activity (group 3). Results: Lavage with povidine-iodine increased the total peritoneal cell count/ washing from 10.4 x 10(6) to 12.4 x 10(6) (p < 0.005), peritoneal bact ericidal activity from 69.2% to 92.7% (p < 0.05), and peritoneal phago cytic activity from 58.9% to 73.7% (p < 0.05) at the end of four hours . Chemotactic indices of peritoneal PMNL before and after lavage were 1.90 and 1.89, respectively. Among the cells in the peritoneal fluid, the proportion of PMNL increased, whereas those of macrophages, lympho cytes, and mast cells decreased (p < 0.005). Conclusions: These result s differ from those that we found previously after saline lavage. Lava ge with 1% povidone-iodine does not increase the detrimental effect of saline lavage; on the contrary, it may even enhance peritoneal defenc e mechanisms. Any detrimental effects of povidone-iodine lavage should be attributed to systemic rather than local toxicity.