Cornea endothelial rose bengal photosensitization. Effect on permeability, sodium flux, and ultrastructure

Rabbit corneal endothelial cells demonstrated an increase of endothelial membrane permeability to inulin following perfusion with 5 X 10(-6) M rose bengal and exposure to 1050 muW/cm2 incandescent light for either 1 min or 5 min when compared to corneas similarly perfused with rose bengal but not exposed to light. Endothelial permeability to dextran was unaltered following the photosensitization reaction. Rose bengal perfusion in the absence of light caused an increase in the unidirectional sodium fluxes (J stroma endothelium and J endothelium stroma); however, a net sodium flux was still present and directed from the stroma to the endothelium. Exposure of rose bengal perfused endothelial cells to incandescent light resulted in a further increase in the unidirectional passive sodium flux in both directions and a reduction in the active component of the sodium flux from stroma to endothelium. This caused a reduction in the net active transport of sodium across the endothelium following the photosensitization reaction. Transmission electron microscopy showed no alteration of endothelial cell ultrastructural integrity following rose bengal perfusion in the absence of light. However, rose bengal perfusion accompanied by exposure to 1050 muW/cm2 incandescent light caused swelling of endoplasmic reticulum and mitochondria. The data indicate that rose bengal photosensitization has an adverse effect on endothelial cell energy production as well as transport and barrier function.