Effects of hyper- and hypo- thyroidism on oxidative stress of the eye in experimental acute anterior uveitis.

Glutathione peroxidase activities and malondialdehyde levels were measured in the homogenated anterior segment of rat eyes with endotoxin induced acute anterior uveitis in euthyroid, hyperthyroid and hypothyroid rats. Malondialdehyde concentrations were found to be significantly increased (p < 0.0005) and glutathione peroxidase activities significantly decreased (p < 0.01) in the hyperthyroid group when compared with controls. Malondialdehyde concentrations of the hypothyroid rat eyes were higher than the control group (p < 0.05), but glutathione peroxidase activities of the same group showed no difference with controls (p > 0.05). These results suggest that excess or deficiency of the thyroid hormones cause alterations in the malondialdehyde levels and glutathione peroxidase activities of the rat eyes in endotoxin induced uveitis, and hyperthyroidism may increase the oxidative stress in endotoxin induced acute anterior uveitis.