Effect of i.v. administered hyperosmotic sodium chloride on carrageenan-induced pleurisy in adrenalectomized and intact rats.

The effect of administration of hyperosmotic NaCl (2 ml, 7.8% NaCl, iv) on carrageenan-induced pleurisy was determined in adrenalectomized and intact rats. The volume of the pleural exudate was significantly reduced 4 h after induction by treatment with hyperosmotic NaCl for both adrenalectomized (0.08 +/- 0.16 ml) and intact (0.03 +/- 0.08 ml) animals compared to their untreated controls (0.56 +/- 0.44 ml and 0.26 +/- 0.15 ml, respectively). Similarly, hyperosmotic NaCl treatment significantly reduced the total number of inflammatory cells in the pleural cavity: 29.60 x 10(6) +/- 7.80 x 10(6) cells for adrenalectomized animals and 28.90 x 10(6) +/- 11.43 x 10(6) cells for intact animals compared to 63.67 x 10(6) +/- 19.92 x 10(6) and 45.26 x 10(6) +/- 12.71 x 10(6) cells for their untreated controls. Treatment with isotonic saline did not affect carrageenan-induced pleurisy. 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.