Alteration of morphology and enzyme activity in dexamethasonª²induced cataract in rat lens

    WANG Jianª²Wei, YAN Hong, WANG Yongª²Qiang, HA Wenª²Jing, DING Zhengª²Hua, GUO Yong

    Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi¬ðan 710038, China

    ¡¾Abstract¡¿ AIM: To observe the morphological features and enzyme activities in dexamethasonª²induced organª²cultured rat lens and to study the mechanisms of steroid cataract. METHODS: One hundred lenses cultured in vitro were divided into 2 groups: control group (DMEM) and dexamethasonª²induced cataract group (DMEM+dexamethason 10 ¦Ìmol/L). Following incubation, the lenses were evaluated daily using a dissecting microscope. On d 1, 3, 5 and 7, 12 lenses of each group were homogenized and the activities of enzymes (catalase, superoxide dismutase, lactate dehydrogenase) were measured, respectively. Two lenses of each group were made into specimen of transmission electron microscopy for the observation of the ultrastructure on d 7. RESULTS: The lenses of control group exhibited mistlike opacity and those of cataract group had dense nuclear opacity on d 7. On d 3, the activities of catalase, superoxide dismutase and lactate dehydrogenase decreased by 34.51%, 7.78%, 15.73% respectively compared with those on d 1. On d 7, they decreased by 84.54%, 30.17%, 40.93% respectively compared with those on d 1. Under electron microscope, the arrangement of fiber cells in control group was in tidy order and the cell membrane, cell junction and organelle were normal, while in cataract group, the arrangement of fiber cells were in untidy order and the lenses consisted of abnormalª²appearing cells which exhibited swollen mitochondria, a large amount of vacuoles and expanded extracellular lacunae. CONCLUSION: Lenses have nuclear cataract in dexamethasonª²induced organª²cultured rat lens. Oxidative stress may be involved in the steroidª²induced cataract formation. ......