Effect of age on superoxide dismutase activity of human trabecular meshwork.

PURPOSE: It has been hypothesized that accelerated aging of the trabecular meshwork, perhaps because of oxidative damage, is involved in the pathogenesis of primary open angle glaucoma. The authors sought to evaluate the effect of donor age on the specific activity of superoxide dismutase and catalase in normal fresh human cadaver trabecular meshwork.

METHODS

Total superoxide dismutase and catalase were assayed in tissue extracts generated from fresh human trabecular meshwork. Cadaver tissue was obtained from 19 donors (18 paired) of a wide age range (30 to 91 years). The assays were performed within 6 hours of enucleation and within 36 hours of donor death. Enzyme-specific activities were calculated using protein concentration of the extract as the denominator.

RESULTS

Multiple regression analysis modeled with age and time from death until the beginning of the experiment was performed. The specific activity of superoxide dismutase declined with age (P = 0.00022; r2 = 0.67). There was no effect of age on catalase specific activity (P = 0.24; r2 = 0.16). The time from donor death until the beginning of the experiment was not a significant factor (P > 0.28).

CONCLUSIONS

The specific activity of superoxide dismutase, but not catalase, demonstrates an age-dependent decline in normal cadaver human trabecular meshwork. The potential role of superoxide dismutase in primary open angle glaucoma, a disorder of the aging trabecular meshwork, warrants further investigation.