Changes in the structure and properties of corpus vitreous and the preservation of enzymatic composition of rabbit antioxidative system under the influence of sulphur hexafluoride gas

摘要

Purpose: To evaluate clinical, physiochemical and biochemical changes in rabbit vitreous body caused by local injection of sulphur hexafluoride gas.Material and methods: The volume of fluid vitreous fraction was measured with Na+, K+, Mg2+, Ca2+ levels and full proteins concentration in both vitreous fractions in 24 New Zealand rabbits at 2, 7 and 14 day after SF6 injection. The activity of superoxide dismutase, catalase and malonyl dialdehyde were used to evaluate the activity of antioxidative enzymatic system. Control group consisting of 6 New Zealand rabbits had no experimental procedures.Results: In the investigated group, the fluid vitreous fraction volume was increased while gelatous one was diminished from 0.08 ml in control group to 0.32 ml in the study group (on day 14). The level of Na+, K+, Mg2+, Ca2+ in the fluid fraction was unchanged. On day 7, we noticed statistically significant increase in protein concentration in comparison with the control group and the study group on 14 day. The activity of superoxide dismutase and catalase as well as the level of malonyl dialdehyde were increased in the fluid vitreous fraction compared to the gelatous one in the control group. After the SF6 injection we did not observe any changes of superoxide dismutase and catalase activities in the gelatous part of vitreous body while in the fluid one there was statistically significant decrease in the enzymatic activity and the MDA level in the whole observation time.Conclusions: The injected sulphur hexafluoride gas caused the damage of the gelatous vitreous fraction with the increase in the fluid one. The oxygen free radicals might trigger these pathological processes.key words: sulphur hexafluoride, intravitreal tamponade, antioxidative enzymatic system, vitreous body