PURPOSE: To detect Evans blue in the normal cornea, attempting to determine the period of maximum concentration of the dye after intravenous injection and to study vascular permeability in an animal model of corneal inflammation induced by alkali burn, after Evans blue injection. METHODS: Fifty rabbits were divided into 3 groups. Group I (25 animals): 20 mg/kg Evans blue were injected and the animals were sacrificed after 8, 10, 12, 14 and 16 hours. The corneas were removed and the dye concentration was measured by a spectrophotometric micromethod. Group II: in 15 animals, 10 hours after injection, the corneas were centrally fragmented with number 6, 8 and 10 mm trephines. Evans blue was extracted the same way as in Group I. Group III: alkali burn was induced in the cornea of the right eyes of 10 animals, using 1 N NaOH. Five days after the procedure, the animals were sacrificed. Ten hours prior to sacrifice, Evans blue was injected. The left corneas were the control. RESULTS: In group I, mean Evans blue concentration is at 10 h: 15.28 ± 0.09 mg/mg. In group II, mean Evans blue concentrations are: 6 mm: 0.93 ± 0.01mg/mg; 8 mm: 1.20 ± 0.06 mg/mg; 10 mm: 1.32 ± 0.05 mg/mg. In group III, mean Evans blue concentrations are: right eyes (alkali burns): 23.74 ± 2.64 mg/mg and left eyes (control): 16.71 ± 2.04 mg/mg. CONCLUSIONS: This is the first time that Evans blue has been quantified in rabbit's cornea. It was possible to detect the dye from 8 to 16 hours after intravenous injection. We can conclude that Evans blue detection is a good method to quantify the alteration of vascular permeability in rabbit's cornea.
Evans blue; Spectrophotometry; Permeability; Cornea; Rabbits
