Abstract
Purpose:
Our prior studies have shown that selected cytokines are elevated in the eye during diabetic cataract formation in a streptozotocin (STZ)-induced diabetic rat model. The objective of this ongoing study is to assess the direct effects of the cytokines IL-1α and IL-4 on elongating lens fiber organization and ultrastructure in a whole-lens culture model.
Methods:
Normal Wistar rat lenses (n=24 animals) were cultured with either IL-1α or IL-4 at the same concentrations measured in STZ-diabetic rat eyes, or were untreated (controls). Following either 24 hours (OD) or 48 hours (OS) in culture, lenses were photographed, decapsulated and fixed for scanning electron microscopic (SEM) analysis.
Results:
Cytokine-treated lenses showed gross structural alterations such as sutural widening, discrete superficial opacities and foci of fiber disruption. Changes manifested as early as 24 hours and were generally more pronounced at 48 hours. Lenses cultured in media without cytokine remained transparent and lacked obvious structural alterations. SEM examination of cytokine-treated lenses revealed regions having a disorganized pattern of swirled fiber ends and areas of elongated ends which often displayed excessively long, disorganized filopodia. In addition, zones of cellular breakdown were present in locations corresponding to gross defects.
Conclusions:
The gross and ultrastructural changes that were noted after cytokine-treatment of normal lenses were consistent with documented changes in STZ-induced diabetic cataracts. These findings support the hypothesis that IL-1α and IL-4 may be involved in the initiation of diabetic cataract formation.