Glucose Permeability Of Human, Bovine, And Porcine Corneas In Vitro

Purpose: To measure glucose flux across human, bovine,and porcine corneas and to determine the diffusion coefficient of each type of cornea. Methods: Diffusion of glucose across human (n = 8), bovine (n = 7), and pig corneas (n = 8) was measured using a modified blind well chamber apparatus (Boyden chamber). Dialysis membranes (n = 7) and nonporous Mylar membranes (n = 7) were used as positive and negative controls, respectively. Glucose concentrations were measured at 30-min intervals with a commercially available glucose meter. Results: The diffusion of glucose through corneas in vitro was calculated by a simple Fickian diffusion model. The diffusion coefficient of glucose is highest for the human cornea (D-HC = 3.0 +/- 0.2 x 10(-6) cm(2)/s) followed by porcine corneas (D-PC = 1.8 +/- 0.6 x 10(-6) cm(2)/s) and bovine corneas (D-BC = 1.6 +/- 0.1 x 10(-6) cm(2)/s) (p < 0.05). The diffusion coefficients of all tested corneas were significantly higher (p < 0.05) than that of dialysis membrane (D-DM = 3.4 +/- 0.2 x 10(-7) cm(2)/s). Conclusion: The glucose diffusion coefficients of human, bovine, and porcine corneas are on the order of 10-6. Human corneas have higher permeability to glucose than either porcine or bovine corneas. Copyright (c) 2006 S. Karger AG, Basel.