Effect of hyperosmotic sodium chloride solution on vascular permeability and inflammatory edema in rats

This study analyzes the effects of treatment with a hyperosmotic NaCl solution on carrageenan-induced inflammatory edema and vascular permeability in rats. Given 15 min before carrageenan, this treatment reduced paw edema measured for up to 6 h by 27 to 44%. Similarly, when the rats were treated 30 min after injection of the irritant, paw volume was significantly reduced (35 to 53%) between 1 and 6 h when compared to that of untreated animals. Increases in vascular permeability were significantly reduced at 30 min (73%) and 1 h (54%) in rats treated 15 min before, and at 1 h (49%) in animals treated 30 min after carrageenan. Treatment with hyperosmotic mannitol or isotonic NaCl solutions did not show any changes in inflammatory response to carrageenan. These data suggest that chemical mediator(s) of inflammation may be involved in the mechanism(s) of action of a hyperosmotic NaCl solution on the acute inflammatory response.