Preliminary Observation And Mechanism Study Of Hydrogen-saline On Selenite-induced Cataract In Rats

Cataract is the leading cause of blindness all over the world and seriously impairsvision and quality of life. It is compelling to explore alternative pharmacological measuresfor the treatment of cataract. Both epidemiological and experimental studies providedevidence that oxidative stress is a major mechanism in the initiation and progression ofcataract. Selenite-induced cataract is a cataract model that is causally-related to oxidativestress. In this study, we tested the potential antioxidative effect and mechanism ofhydrogen-saline on cataractogenesis in a selenite-induced cataract rat model.ObjectiveThe aim of this study was to investigate the potential antioxidative effect andmechanism for the protective effects of hydrogen-saline on selenite-induced cataract inrats. Methods1. Preliminary study of hydrogen-saline on selenite-induced cataract in ratsNeonatal rat pups of the Sprague-Dawley on the7th day of age were divided into thenormal control group （A，n=12）, the cataract group （B，n=12）, H₂-saline prevented group（C，n=12）, H₂-saline treatment group （D，n=12）, late H₂-saline treatment group （E，n=12）and H₂-saline group （F，n=8）. The cataract group, H₂-saline prevented group, H₂-salinetreatment group and late H₂-saline treatment group rat pups received a singlesubcutaneous injection of sodium selenite （25μmol/kg body weight） on postpartum day12.H₂-saline prevented group, H₂-saline treatment group and late H₂-saline treatment grouprat pups also received an intraperitoneal injection of H₂-saline （5ml/kg body weight） oncedaily on postpartum days8-12, postpartum days8-17, postpartum days17-21. H₂-salinegroup rat pups only received an intraperitoneal injection of H₂-saline （5ml/kg body weight）once daily on postpartum days8-17. The lenses opacification in eyes of rat pups wasassessed on the26th day of age by slit-lamp examination. The lenses were analyzed foractivities of SOD, levels of GSH and MDA. All the data were analyzed using the SPSS18.0statistical package.2． The mechanism study of inhibition effects of hydrogen-saline on selenite-inducedcataract in ratsThen based on the first set of experiment observation, rat pups of Sprague-Dawleywere divided into the normal control group （A，n=20）, the cataract group （B，n=20） andH₂-saline treatment group （C，n=20）. The cataract group and H₂-saline treatment group ratpups received a single subcutaneous injection of sodium selenite （25μmol/kg body weight）on postnatal day12. H₂-saline treatment group also received an intraperitoneal injection ofH₂-saline （5ml/kg body weight） daily from postnatal day8to postnatal day17. Thedevelopment of cataract was assessed weekly by slit-lamp examination for2weeks. Aftersacrifice, extricated lenses were analyzed for activities of SOD, CAT, Gpx, GR and GST,levels of MDA, GSH and total sulfhydryl contents. Then, the retinas were removed formeasurement of activities of SOD, CAT, Gpx and GR, levels of GSH and MDA contents.All the data were analyzed using the SPSS18.0statistical package. Results1. Preliminary study of hydrogen-saline on selenite-induced cataract in rats（1） Lens opacification observed under slit-lamp microscopeThe normal control group and H₂-saline group rats exhibited complete transparencyof lens. Subcutaneous injections of sodium selenite resulted in lens opacities in all eyes inthe cataract group. Among these,16.67%（4/24）of the eyes developed nuclear opacity（Grade V） and83.33%（20/24）of the eyes developed mature cataract of entire lens （GradeVI）. In H₂-saline prevented group,25%（6/24）of the eyes developed nuclear opacity（Grade V） and75%（18/24）of the eyes developed mature cataract of entire lens （Grade VI）.In late H₂-saline treatment group,29.17%（7/24）of the eyes developed nuclear opacity（Grade V） and70.83%（17/24）of the eyes developed mature cataract of entire lens （GradeVI）. In contrast, in H₂-saline treatment group,33.33%（8/24）of the eyes developed diffusenuclear opacity （Grade III）,41.67%（10/24）of the eyes developed partial nuclear opacity（Grade IV）,16.67%（4/24）of the eyes developed nuclear opacity （Grade V） and8.33%（2/24）of the eyes developed mature cataract of entire lens （Grade VI）. There wasstatistically significant difference between H₂-saline treatment group and the cataractgroup （χ²=30.48，P<0.05）. However, there were no statistically significant differencesbetween the cataract group, H₂-saline prevented group and late H₂-saline treatmentgroup（χ²=1.06，P>0.05）.（2） Biochemical indicators of lensCompared with the cataract group, the mean activities of SOD, the levels of GSHwere elevated and the level of MDA was decreased in H₂-saline treatment group （P<0.05）.However, there were no statistically significant differences between the cataract group,H₂-saline prevented group and late H₂-saline treatment group （P>0.05）. And there was nostatistically significant difference between the normal control group and H₂-saline group（P>0.05）.2. The mechanism study of inhibition effects of hydrogen-saline on selenite-inducedcataract in rats （1） Lens opacification observed under slit-lamp microscopeThe normal control group rats exhibited complete transparency of lens. Subcutaneousinjections of sodium selenite resulted in lens opacities in all eyes in the cataract group.Among these,20%（8/40）of the eyes developed mature cataract of entire lens （Grade VI）,25%（10/40）of the eyes developed nuclear opacity （Grade V） and55%（22/40）of the eyesdeveloped mature cataract of entire lens （Grade VI）. In contrast, in H₂-saline treatmentgroup,5%（2/40）of the eyes developed slight nuclear opacity （Grade II）,25%（10/40）of the eyes developed diffuse nuclear opacity （Grade III）,45%（18/40）of the eyesdeveloped partial nuclear opacity （Grade IV）,15%（6/40）of the eyes developed nuclearopacity （Grade V） and10%（4/40）of the eyes developed mature cataract of entire lens（Grade VI）. There was statistically significant difference between H₂-saline treatmentgroup and the cataract group （χ²=44.06，P<0.05）.（2） Biochemical indicators of lensCompared with the cataract group, the mean activities of antioxidant enzymes SOD,CAT, Gpx, GR and GST, levels of GSH and total sulfhydryl contents were higher whereasthe level of MDA was lower following treatment with hydrogen-saline （P<0.05）.（3） Biochemical indicators of retinasThe retinas of rats in each group were analyzed for activities of SOD, CAT, Gpx andGR, the levels of GSH and MDA contents. There were no statistically significantdifferences between the normal control group, the cataract group and H₂-saline treatmentgroup （P>0.05）.Conclusions1. Hydrogen-saline can inhibit and postpone the development of selenite-inducedcataract in rats without lenticular toxicity. However, hydrogen-saline could not preventand reverse selenite-induced cataract under current conditions.2. This is an initiative report that hydrogen-saline can inhibit selenite-induced cataractin rats. It acts via maintaining antioxidant enzymes and GSH, protecting the sulfhydrylgroup, and inhibiting lipid peroxidation. 3. Hydrogen-saline had no remarkable influence on the balance ofoxidation-reduction reactions on the retinas of rats.