Glucose permeability of human, bovine, and porcine corneas in vitro.
OBJECTIVE
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).


CONCLUSIONS
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.
Myung
David
D
Department of Ophthalmology, Stanford University, Stanford, Calif., USA.
Derr
Kristen
K
Huie
Philip
P
Noolandi
Jaan
J
Ta
Kathryn P
KP
Ta
Christopher N
CN
D000818:Animals; D001692:Biological Transport; D002417:Cattle; D003315:Cornea / Q000378:metabolism*; D004058:Diffusion; D015194:Diffusion Chambers, Culture; D005947:Glucose / Q000493:pharmacokinetics*; D006801:Humans; D010539:Permeability; D013552:Swine
D005947:Glucose