The effects of hypertonic salicylate on neutrophil migration and vascularization in the rat cornea

Thermal cauterization of the center of the rat cornea results in emigration of neutrophils into the extravascular limbal tissue and blood vessel growth into the cornea. In this study, 1.0 M sodium salicylate, 1.0 M sodium chloride, and ointment vehicle were administered to normal and cauterized rat corneas for periods of 6, 48, and 144 h. When applied to the normal cornea, salicylate resulted in a marked increase in neutrophils in the limbal tissue at 6 h, but an inhibition at 48 h. Similarly, for the cauterized corneas, administration of salicylate increased the extent of neutrophil emigration at 6 h, but this effect was not sustained at 48 h. Neither vehicle nor sodium chloride had any effect on the extravascular neutrophil population. After 6 days, administration of the vehicle resulted in a slight increase in vascular growth into the cornea, whereas sodium salicylate caused a decrease. These findings indicate that hypertonic (1 M) sodium salicylate does not inhibit the emigration of neutrophils from limbal vessels of cauterized rat corneas, but does appear to have a cytotoxic effect on the tissues and on blood vessel endothelial cells.