Localised fibre cell swelling characteristic of diabetic cataract can be induced in normal rat lens using the chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid

Chloride channels are known to be involved in the regulated volume decrease that occurs when the rat lens is exposed to hypotonic challenge. We now re port that chloride channel blockage makes the rat lens gain water under iso tonic conditions, suggesting that chloride and water fluxes may also play a n important role under resting conditions. Histological comparison of hypot onically and isotonically swollen rat lenses revealed a significant differe nce: in the former, fibre cells were swollen from the periphery inwards, wh ile in the latter, swollen fibre cells were confined to a discrete cortical zone which was located 150-200 mu m from the lens surface with cells on ei ther side of this zone appearing unaffected. This localised fibre cell swel ling is remarkable because of its similarity to the situation in the diabet ic rat lens.