Inhibitory effect of taurine on lens epithelial cell apoptosis / 中国组织工程研究

ABSTRACT

BACKGROUND:Taurine is an important non-enzymatic system antioxidant in the lens.The mechanism of its anti-oxidative effect is mainly to protect lens from oxidative injury by anti-lipid peroxidation.OBJECTIVE:This study was to observe the effect of exogenous taurine on lens epithefial cell apoptosis-induced by H2O2 in vitro.DESIGN:A randomized controlled animal experiment.SETTING:Department of Ophthalmology,Affiliated Hospital of Qingdao University Medical College.MATERIALSSeventy-five adult New Zealand standard tabbits,of either gender,weighing 1.5-2.5 kg,were provided by Qingdao Laboratory Animal Center.Reagent kit for in situ detecting cell apoptosis(Sigma Company,USA),taurine and H2O2(Shanghai Guangda Chemical Reagent Factory,China)were included in this study.METHODS:This study was performed in the Department of Ophthalmology and Central Laboratory.Affiliated Hospital of Qingdao University Medical College from Mav 2005 to June 2007.Rabbit lenses were harvested and randomly divided into 3 groupscontrol group,in which,clear lenses were incubated in non-serum and non-phenolsulfonphthalein MEM medium which was renewed every 24 hours,H2O2 group,in which,clear lenses were incubated in non-serum and non-phenolsulfonphthalein MEM medium containing 1 mmol/L H2O2 with addition of 62 μL H202(30 g/L)every 6 hours,and H2O2+taurine group,in which,clear lenses were incubated in non-serum and non-phenolsulfonphthalein MEM medium containing 1 mmol/L H2O2 and 10 g/L taurine.which was renewed every 6 hours.The protocol was conducted in accordance with ethical guidelines for the use and care of animals.MAIN OUTCOME MEASURES:Observation of lens opacity 6.12,24.48 and 72 hours after culture;Lens epithelial cell apoptosis determined by DNA in situ end labeling and DNA fragment analysis.RESULTS:Lens opacityThe lens opacity in the H2O2 group was aggregrated gradually along with the time of oxidative injury.The lens opacity in the H2O2 group was severer than that in the H2O2+taurine group.Lens epithelial cell apoptosisThere were no apoptotic cells in the control group within 72 hours.The number of apoptotic cells in the H2O2 group was increased gradually with the prolonged time of oxidative injury.Till the 72nd hour,the cells were all tamed into apoptotic cells.A few aopototic celIs were found in the H2O2+taurine group since hour 24,and then were more and more,and the number of apoptotic cells accounted for about 30%at hour 72.The apoptotic rate in the H202+taurine group was significantly lower than that in the H2O group at each time point(q=8.6845,P＜0.01).There was no significant difference in apoptotic rate between the H202+taurine group and the control group (P＞0.05). Findings of DNA fragmentation assayThe DNA"ladder"was found in the H2O2 group at hours 24,36,48 and 72,while no DNA"ladder"but only normal electrophoresis straps were present in the other two groups 24 hours after culture.CONCLUSION:Taurine can inhibit the oxidative injury-induced apoptosis of rabbit lens epithelial cells,and alleviate lens opacity.