Effects of Temperature on the Proliferation of Human and Fish Lens Epithelial Cells

Abstract

Crystallins are proteins that confer refractive properties to the crystalline lens. All vertebrate lenses contain α- and β-crystallins, and often a third major crystallin. Crystallins can have additional non-refractive functions; α-crystallins act as heat shock proteins, protecting lenses from heat-induced denaturation, and γ-crystallins are thought to be cryoproteins, protecting lenses from extreme cold. The concentration of α-crystallins is higher in mammalian lenses than in teleost lenses, while the opposite is true for γ-crystallins, suggesting that mammalian lenses would be better protected in warmer conditions and teleost lenses better protected in colder temperatures. This study determined whether temperature affects the growth of lens epithelial cells (LECs) derived from human and fish lenses. Both human and rainbow trout fish LECs were cultured (n = 4 each) and grown for 1, 2, 4, 6, 8 and 12 days at the optimal (37°C and 18°C, respectively), higher than optimal (42°C and 25°C, respectively) and lower than optimal temperatures (32°C and 10°C, respectively). At optimal temperatures, both fish and human LECs grew optimally. Higher temperatures were more deleterious to the proliferation index than lower temperatures for both human and fish LECs. Mitotic cells were non-existent in fish LECs grown at high temperatures. The sizes of the cells did not greatly change with temperature with either species, but human cells at non-optimal temperature tended to clump over time. Human LECs at the optimal temperature maintained their random distribution. Fish LECs at optimal temperatures moved from a random distribution to a clumped distribution, but lower temperatures had the opposite effect; LECs moved from a clumped to a random distribution. Only the high temperature group of fish LECs maintain their random organisation.