Effect of oxidized glutathione on the barrier function of the corneal endothelium

Effects of glutathione on the corneal endothelium were reexamined. Four kinds of solutions were made: oxidized glutathione (GSSG) was added to a basic solution which does not contain glutathione (GSSG-0) at a concentration of 0.03 mM, 0.3 mM or 3 mM to make GSSG-0.03, GSSG-0.3 or GSSG-3, respectively. Paired rabbit corneas were perfused separately, and the endothelial permeability (Pac) to carboxyfluorescein was determined. Between the paired corneas perfused with GSSG-0 and GSSG-0 or GSSG-0 and GSSG-0.03, there was no significant difference in the Pac. A significant difference in this factor was seen between the paired corneas perfused with GSSG-0 and GSSG-0.3 or GSSG-0 and GSSG-3 (P less than 0.01). The ratio of GSSG-0 to GSSG-0.3 for Pac, 1.18 +/- 0.16, and that of GSSG-0 to GSSG-3, 1.14 +/- 0.07, were significantly greater than the left-right ratio for Pac obtained when the paired corneas were perfused with GSSG-0, 1.01 +/- 0.10 (mean +/- SD, n = 8) (P less than 0.025). The corneal swelling rate (micron/hr) was 7.9 +/- 4.9 for the corneas perfused with GSSG-0 and 8.4 +/- 5.4 (mean +/- SD, n = 6) for those perfused with GSSG-0.3; difference was not significant. Addition of GSSG at a concentration of 0.3 mM or more to the irrigating solution was further beneficial to the corneal endothelial barrier function and a solution containing GSSG may be safer for patients with vulnerable corneas.