The effects of high ambient XXXX on the radiosensitivity of retinal microvascular endothelial cells and pericytes.

@entity1 @entity6 @entity1161 @entity5 @entity989 @entity413
PURPOSE: The metabolic peturbations of @entity6 cause functional and structural changes in the retinal microvasculature which are termed @entity6 . Exposure of the eye to ionising @entity1161 results in @entity989 with a clinical manifestation known as @entity989 . Anecdotal studies have suggested that exposure to even low levels of ionising @entity1161 may accelerate development of pathological changes in the retinal vessels of @entity1 with @entity6 . This in vitro study was designed to test the hypothesis that the combination of a high ambient @entity413 environment (mimicking hyperglycaemia and @entity6 ) along with exposure to ionising @entity1161 would result in more accentuated damage to cultured @entity989 . METHODS: Retinal microvascular endothelial cells and pericytes were propagated for 5 days in either 5 mM (euglycaemia) or 15 mM (hyperglycaemia) @entity413 . Cells were irradiated with 250, 500 or 1000 cGy of ionising @entity1161 using a 6 MV beam photon accelerator which was used for radiotherapy. Similarly treated but unirradiated cells were used as controls. DNA damage was assessed using the single-cell gel electrophoresis (comet) assay. RESULTS: Unirradiated control cells pre-exposed to @entity413 at either 5 mM or 15 mM for 5 days showed no significant difference in mean percentage tail DNA representing damage. However, in both pericytes and endothelial cells exposed to ionising @entity1161 , cells cultured in 15 mM @entity413 showed significantly higher levels of DNA damage compared with those cultured in 5 mM @entity413 , with maximal differences being seen at the higher @entity1161 doses (500 and 1000 cGy). CONCLUSIONS: This study has demonstrated that retinal microvascular cells cultured in high @entity413 express more DNA damage when exposed ionising @entity1161 . These findings have important implications for the management of @entity1 with @entity6 if they require radiotherapy for @entity5 .
