Corneal angiogenesis based on different protocols of alkaline cauterization in murine models

Abstract

Purpose: To establish and compare protocols of alkaline cauterization for inducing corneal angiogenesis in murine models. Methods: Twenty-four adult Wistar rats were distributed into four groups (G1, G2, G3, and G4). The right eye cornea from each rat was cauterized using filter paper (3 mm), soaked in a solution of silver and potassium nitrates (3:1). Cauterization times were 10 (G1 and G4), or 20 seconds (G2 and G3). Cauterized corneas were washed with Ringer's lactate solution. The filter paper was either removed before washing (G1 and G2), or kept on the corneas (G3 and G4). Corneas were photographed at multiple time points (2, 4, 6, 8, 11, 13, and 15 days after the procedure), and neovascularization parameters were assayed. Results: Neovascularization was observed in 66% of G1 corneas, and 100% of G2, G3, and G4 corneas. On day 15, G1 corneas showed smaller vascularized areas (12.63 ± 12.59%) compared to those in the G3 (41.95 ± 17.32%) and G4 (33 ± 11.74%) (P < 0.05) groups. Conclusions: The silver and potassium nitrate solution effectively induced corneal angiogenesis. The G2, G3, and G4 protocols showed excellent reproducibility, and induced vascularization in 100% of corneas.

Effect of metronidazole ophthalmic solution on corneal neovascularization in a rat model

“…Corneal inflammatory angiogenesis was induced through a protocol of punctual alkaline cauterization in the right eye [24]. All procedures were performed with animals under general [25] and topical anesthesia with 0.5% proxymetacaine eye drops (Alcon, São Paulo, Brazil).…”

“…All procedures were performed with animals under general [25] and topical anesthesia with 0.5% proxymetacaine eye drops (Alcon, São Paulo, Brazil). A circular disc of filter paper with a diameter of 3 mm, saturated with a solution of 75% silver nitrate (Synth, Diadema, Brazil) and 25% potassium nitrate (Dinâmica Contemporary Chemistry Ltda., Diadema, Brazil), was pressed onto the axial region of the cornea, for 20 s [24]. Excess silver and potassium nitrate were removed by rinsing the eye.…”

“…Treatments started immediately postinjury and all instillations (10 lL of 0.1% metronidazole, 0.5% metronidazole, or PBS) were performed at regular intervals of 6 h, for up to 30 days. Postinjury, the animals received tramadol hydrochloride (5 mg/ kg; Cristália, Itapira, Brazil) by the subcutaneous route every 8 h, for 10 days [24].…”

“…In addition, fluorescein eye stain (fluorescein sodium ophthalmic strips; Ophthalmos S.A., São Paulo, Brazil) was performed. Corneas were laterally and frontally photographed using digital equipment (TRC-50DX, Topcon, Japan) on days 0, 2, 7, 12, 15, 18, 21, 26, and 30 [8,24] and the images of CNV were evaluated by a blinded investigator.…”

“…Burn intensities were studied from lateral images [24]. They were scored based on the appearance of blisters and on the extent of their elevation from the corneal surface: 0 (no blister, not raised above corneal surface), 1 (a small blister that is slightly raised above the surface), 2 (a medium blister that is moderately raised above the surface), and 3 (a large blister) [26].…”