Abstract
Purpose: :
Although the subcapsular cataract (ASC) is morphologically characterized as aberrant accumulation and proliferation of lens epithelial cells (LECs), the mechanisms underlying plaque formation localized beneath the anterior capsule have not been fully understood. To elucidate the mechanisms we obtained specimens of the anterior capsule from patients with ASC for immunohistochemical assays.
Methods: :
During cataract surgery the anterior lens capsules including opacities were collected from five (5) patients (aged from 35 to 67 years, mean 53 years) without history of ocular trauma. The capsules were immersion fixed in 10% paraformaldehyde. Thin 4µm sections were stained with hematoxyline and eosin (HE), periodic acid Schiff (PAS) and Masson–trichrome (MT) for light microscopical analyses. Sections were also immunostained with antibodies against Type IV collagen and laminin as components of basement membrane, vimentin as a cytoskeletal element, and transforming growth factor ß (TGF–ß) as a cell activating factor.
Results: :
Light microscopical analyses showed that LECs in the plaque area were irregularly arranged beneath the anterior capsule. The opacity was evenly stained with HE and PAS, but stained unevenly with MT. Immunoactivities against Type IV collagen, laminin, vimentin, and TGF–ß were pronounced in the plaque compared with other areas. Except for the plaque LECs appeared intact.
Conclusions: :
The observation suggests that localized activation of LECs beneath the lens capsule results in subcapsular opacification with collagenous fibers.
Keywords: cataract • pathology: human • immunohistochemistry