Abstract: By using the methods of Electron Paramagnetic Resonance(EPR)、chemilumineseence and fluoresence spectrophotometry, the contents of free radicals、superoxide dismutases(SOD) and water soluble lipid peroxides in tears in the normal eyes(100 cases) and keratoplasty eyes(42 cases) have been investigated. The results indicated that the spin density of free radicals was (3.6±0.58)×10¹² spins/mL, SOD was (3.84±1.45) μg/L, water soluble lipid peroxide was (12.912±1.691) U/mL in the normal tears. Two peaks were found in every target after 24 hours and 21 day of the keratoplasty operation. Both peaks regularily. An obvious interrelation was there in every pair of the three targets. However, the special changes of 5 cases of 42 cases proved free radicals and lipid peroxides increased continuously and the rejection was inereased. These findings suggest that there is free radical reaction mechanism in the rejection and that after keratoplasty supervising and determining free radical、SOD and water soluble lipid peroxide are important for preventing the rejection.

Key words: electron paramagnetic resonance, free radical, superoxide dismutase, water soluble lipid peroxide, keratoplasty