Ultrastructure of the lens anterior capsule in secondary cataract associated with uveitis under an electron microscope

Abstract

Objective: To observe the ultrastructure of lens epithelium cells in cataract associated with uveitis. Methods: A cross-sectional study. Seven patients(7 eyes) received phacoemulsification in Peking University First Hospital from August 2016 to March 2017 due to complicated cataract associated with uveitis[2 males and 5 females,with an average age of (49±20) years] and 3 patients of age-related cataract (3 eyes, females, aged 54, 71, 74 years) were enrolled. Anterior capsule samples were collected during surgery. Transmission electron microscopy was performed. The cell morphology, the proportion of cell nuclear and organelle changes and the proportion of apoptosis in cataract associated with uveitis were described statistically by x±s or median (range). Results: Spindle-shaped epithelial cells were observed in cataract associated with uveitis (100%), while 28.00%,16.67%,16.67% of spindle-shaped epithelial cells were observed in age-related cataract. The organelle changes included mitochondria swelling and damage to the tight cell junction in cataract associated with uveitis. The tight junction between two cells was damaged in different degrees, only 8.33% (0-16.67%)of the cell nuclei appeared normal, and increased chromatin density(47.07%±22.28%), nuclear pyknosis(38.02%±19.61%) and nuclear fragmentation (9.96%±8.10%) were observed in cataract secondary to uveitis. The apoptosis rate was (48.16%±26.66%) in cataract associated with uveitis and correlated to the duration of intraocular inflammation. While the apoptosis rate were 0, 8.33%, 0 in age-related cataract patients. No autophagosome was observed in cataract associated with uveitis. Conclusions: Ultrastructure changes existed in lens epithelium cells in cataract associated with uveitis. The increased rate of apoptosis and inhibition of autophagy could be the possible mechanism of cataract formation in uveitic eyes. (Chin J Ophthalmol, 2018, 54: 357-362).