Superoxide dismutase activity in the lens capsule of patients with pseudoexfoliation syndrome and cataract

Abstract

To evaluate the activity of the antioxidative enzyme superoxide dismutase (SOD) in the anterior lens capsule of patients with cataract complicating pseudoexfoliation syndrome (PEX) in an attempt to determine the role of the oxidative mechanisms in the etiopathogenesis of this disorder. Departments of Ophthalmology and Biochemistry, Ankara University School of Medicine, Ankara, Turkey. At the beginning of phacoemulsification surgery, the anterior lens capsules in 21 eyes with PEX and cataract (group A) and those in 24 eyes with cataract alone (group B) were collected with continuous curvilinear capsulorhexis and were frozen at -20 degrees C. At the time of analysis, the specimens were thawed and centrifuged and the supernatants of the homogenate obtained from the samples were analyzed for the activity of the enzyme SOD. The mean age of patients was 74.8 years +/- 5.5 (SD) in group A and 71.7 +/- 5.6 years in group B. The specific activity of SOD was 17.6 +/- 10.8 IU/mg and 4.36 +/- 1.80 IU/mL in group A and 9.9 +/- 12.9 IU/mg and 2.71 +/- 2.61 IU/mL in group B. Superoxide dismutase activity was significantly higher in group A patients than in group B patients (P = .022 and P = .011, respectively). The increase in SOD activity in the lens capsule of patients with PEX and cataract suggests that oxidative mechanisms play a role in the etiopathogenesis of cataract in PEX. This suggests that SOD activity may be increased as a compensatory mechanism to eliminate this oxidative stress.