Endothelial Function of Cornea Preserved in Korean Corneal Storage Media

PURPOSE: To evaluate the endothelial function of cornea preserved in newly developing korean corneal storage media (CS002, CS003) by estimating the permeability of corneal endothelium and the change of corneal thickness. METHODS: The cornea were divided into six experimental groups - fresh group immediately after enucleation, 4degrees Cmoist chamber group preserved for 24 hours and 48 hours, Optisol & CS002 group for 1, 3, 5, and 7 days, and Likorol & CS003 group for 7, 10, and 14 days after enucleation, and then corneal endothelial permeability(Pac) was measured using carboxyfluorescein solution. Corneal thickness was measured using pachymeter(fine focus adjustment) of the specular microscope. RESULTS: Corneal endothelial Pac (x1 0(- 4) cm/min) was 3.64+/-0.33 in fresh group, 4.79+/-0.28 in 4degrees Cmoist chamber group for 24 hours. Each endothelial Pac of CS002 group at 5 and 7 days was 5.81+/-0.55 and 5.65+/-0.58, which were different with 4degrees Cmoist chamber preservation group for 24 hours(p<0.05) but not different with Optisol groups at same days. Each endothelial Pac of CS003 group at 7, 10, and 14 days was 4.34+/-0.34, 4.66+/-0.59, and 4.66+/-0.27, which were not different from those of Likorol. Each corneal thickness of CS002 and Optisol group at 7days was 417.80+/-19.37 mu m and 421.00+/-19.75mu m, which were resemble increment. Corneal thickness was 426.75+/-22.43mu m in CS003 group and 476.00+/- 40.08mu m in Likorol group at 7days. There was statistical difference between the two group(P<0.05), and this difference was sustained for 14days (P<0.05). CONCLUSION: There was no difference in the effect on corneal endothelial permeability between korean corneal storage media such as CS002 and CS003, and that of previous corneal storage media such as Optisol and Likorol. Corneal thickness of cornea preserved in korean corneal storage media was thinner than that of Likorol.

Protective Effect of Hyaluronic Acid on the Corneal Endothelial Function Against Free-Radical Damage

PURPOSE: To investigate the protective effects of hyaluronic acid with glutathione and ascorbic acid on corneal endothelial function against free-radical damage. METHODS: bovine corneal endothelial(BCEN) cells were treated with a flux of chemically generated superoxide anion produced by the combination of 1 mM hypoxanthine and 0.06 U/ml xanthine oxidase(HX-XO) for 10 minutes, and rabbit corneas were mounted in the dual-chamber specular microscope and perfused with bicarbonate Ringer(BR) solution for one hour and their endothelial surface was exposed to HX-XO for five minutes, and then perfused with glutathione, hyaluronic acid, or ascorbic acid in BR solution for three hours. BCEN cells was observed using MTT assay and rabbit corneal thickness was measured every 15 minutes and corneal swelling rates were calculated by linear regression analysis. Also, corneal endothelial permeability was measured using carboxyfluorescein and fluorometer. RESULTS: MTT assay showed less cytotoxicity in the cells treated with glutathione, hyaluronic acid, or ascorbic acid compared to HX-XO alone. Glutathione, hyaluronic acid, or ascorbic acid reduced the rabbit corneal swelling caused by HX-XO. Corneal endothelial permeability(Pac) increased in corneas perfused with HX-XO(7.88 x 10 cm/min) while those with BR had Pac of 4.54 x 10 cm/min. Following treatment with glutathione, hyaluronic acid, or ascorbic acid, Pac decreased to 4.96, 6.81, and 5.25 respectively(p<0.05). CONCLUSIONS: In conclusion, these data suggest that hyaluronic acid scavenges HX-XO-generated oxyradicals as well as glutathione and less likely ascorbic acid.

The Change of Corneal Endothelial Permeability and Corneal Thickness after Topical Steroid Treatment

Changes of corneal endothelial permeability and corneal thickness after instillation of topical steroid was evaluated. In five rabbits, 0.1%dexamethasone eye solution was dropped into right eyes, and in another five rabbits, 1%prednisolone acetate eye solution was dropped into right eyes, and each left eyes were used as a control with dropping of Tears Naturale(r)II (Alcon-couvreur, Belgium). After dropping eyedrops for seven days, corneal endothelial permeability and corneal thickness were measured. Mean corneal thickness changed from 371.4 micrometer to 334.2 micrometer after dropping eyedrops in 0.1%dexamethasone group, and from 375.8 micrometer to 347.8 micrometer in control group where no statistical difference was noted between the two groups. Corneal endothelial permeability was 3.58x10(-4)cm/min in 0.1%dexamethasone group, and 3.54x10(-4) cm/min in control group(p>0.05). Mean corneal thickness changed from 347.4 micrometer to 323.8 micrometer after dropping eyedrops in 1% prednisolone acetate group, and from 342.4 micrometer to 335.6 micrometer in control group. There was also no statistical difference between the two groups. Corneal endothelial permeability was 4.08x10(-4)cm/min in 1%prednisolone acetate group, and 4.26x10(-4) cm/min in control group(p>0.05). In conclusion, topical application of 0.1%dexamethasone or 1%prednisolone acetate for a short period may have no effect on corneal endothelial permeability and thickness.

The Effect of Taurine on Corneal Endothelial Damage by Free-radicals

PURPOSE: To investigate the protective effect of taurine on the corneal endothelial damage by oxidative stress. METHODS: Rabbit corneas were mounted in the dual-chambered specular microscope and perfused with bicarbonate-Ringer solution(BR) for 1 hour, and endothelial surface was treated with hypoxanthine-xanthine oxidase(HX-XO) for 5 minutes, and perfused with BR for 3 hours in control group, while perfused with 0.5, 1.0, 2.0 mM taurine in BR in test group. Corneal thickness was measured every 15 minutes and corneal swelling rates were calculated by linear regression analysis. Also, corneal permeability was measured using carboxyfluorescein and fluorometer. Using bovine corneal endothelial cells, MTT assay was done. RESULTS: On MTT assay, cytotoxicity of HX-XO group was 47.69% while those treated with 0.5, 1.0, 2.0 mM taurine were 36.22%, 29.73%, 24.90%, respectively(P<0.05). 0.5, 1.0 and 2.0 mM taurine group (12.88, 10.75 and 8.95 um/hr, respectively) reduced the HX-XO-induced corneal swelling rate(20.08 um/hr)(P<0.05). Corneal endothelial permeability(Pac) showed 7.96 x 10(-4) cm/min in corneas perfused with HX-HO. Also, each taurine solutions markedly reduced Pac(7.00+/-0.29 x 10(-4), 6.51+/-0.25 x 10(-4) and 5.37+/-1.41 x 10(-4) cm/min, respectively)(P<0.05). CONCLUSIONS: The results of this study showed that taurine may prevent hydrogen peroxide-induced corneal endothelial damage.

The Effect of Mitomycin-C on the Function of Corneal Endothelial Cells in Rabbit

The purpose of this study is to investigate the toxicity of mitomycin-C[MMC]to the corneal endothelial cells, which is medical adjunct to pterygium and glaucoma surgery.Rabbit corneas were mounted in the in-vitro dual-chambered specular microscope.Corneal endothelium was perfused with the glutathione-bicarbonate-Ringer[GBR]solution for one hour, then, perfused with 0.02%, 0.01%, and 0.005%MMC in GBR solution in experimental groups, and with GBR solution only in control group.Corneal thickness was measured every 15 minutes during perfusion and corneal swelling rate was calculated.Corneal endothelial permeability was also measured in another experiment.In MMC-mixed group, the early swelling rate decreased due to osmolarity of MMC, but after removal of MMC, the swelling rate increased compared to that of the control group.The pattern of increase was not a linear form, but a secondary curve with the plateau. In 0.02%and 0.01%MMC group, corneas swelled significantly, but not in 0.005%group.Corneal endothelial permeability was 4.21 +/-0.50 x10-4cm/min at 0.005%MMC, 4.10 +/-0.93 x10-4cm/min in control, and 4.25 +/-0.48 x10-4cm/min at 0.01% MMC, 3.73 +/-0.73 x10-4cm/min in control. No significant changes in permeability was observed.In conclusion, MMC of 0.01% or higher exposed to corneal endothelial cells induced corneal swelling of which mechanism was thought to be due to inhibition of Na/K-ATPase by MMC.

Effect of Dorzolamide on Corneal Endothelium

The purpose of this study was to investigate the effect of 2% dorzolamide, a topical carbonic anhydrase inhibitor, on corneal endothelium. Corneal endothelial permeability, central corneal thickness, central corneal endothelial cell density and intraocular pressure were measured in both eyes before(baseline) and after the use of 2% dorzolamide t.i.d. in one eye for one week. There was significant decrease in intraocular pressure(p=0.04) after the use of 2% dorzolamide t.i.d. for one week, but there were no significant changes in corneal endothelial permeability, central corneal thickness and central corneal endothelial cell density(p>0.05 in all).

The Effect of Fluorescein and Indocyanine Green on Corneal Endothelial Function

Both sodium fluorescein[FL] and indocyanine green[ICG] were used for fundus angiography. Recently, these were also used during cataract surgery for enhancement of capsular visualization in white mature or hypermature cataract. So, ICG and FL may influence corneal endothelial function if left in anterior chamber. To evaluate the effect of intracameral FL or ICG on corneal endothelial function, rabbit corneas were isolated &mounted in the in-vitro specular microscope for endothelial perfusion. Experimental corneas were perfused with different concentrations of FL or ICG. Control corneas were perfused with glutathione-bicarbonate Ringer solution[GBR]. Corneal thickness was measured every 15 minutes during the perfusion and corneal swelling rates were calculated. Corneal endothelial permeability[Pa c] was measured according to the method of Watsky et al. The corneas perfused with FL, 2.5% deswelled probably due to high osmolarity. Swelling rates of corneas perfused with 1% and 0.5% FL did not differ significantly from control[p>0.05]. The corneas perfused with 0.01%, 0.005%, 0.002%, and 0.001% ICG swelled significantly[p0.05]. Pa c in corneas perfused with ICG, 0.005% increased markedly compared to control while corneas perfused with FL, 1% showed decreased permeability. The results of this study showed that FL did not affect endothelial function of rabbit cornea in relatively high concentrations while ICG affected endothelial function even in lower concentrations. With respect to clinical use of intracameral ICG, close attention must be paid.