Cyclic tetrasaccharide delays cataract formation in the lens in vitro

The aim of this study was to test whether cyclic tetrasaccharide could prevent cataract formation in isolated porcine lenses in vitro. Porcine eyes were cut at the midperiphery with a razor blade and pressure was applied to the globe to eject the lens without touching. The isolated lenses were then washed with saline and transferred with a spoon to wells of a 24-well multidish with a lid. The lenses were incubated in saline, 1, 10, 20, 50, 75, and 100 mM trehalose or cyclic tetrasaccharide in saline for 40 days at room temperature and in room humidity. Solution change or aeration was not done during the period. The lenses were observed with a dissecting microscope with transmitting light source and the images of the lenses were captured through a CCD camera into a computer. The lens opacity was measured as mean density in a circle area placed inside the lens. Cyclic tetrasaccharide at 75 mM and 100 mM concentrations significantly delayed the development of lens opacity compared with saline, trehalose at any concentrations, and cyclic tetrasaccharide at 50 mM or lower concentrations over the course of 40 days. The lenses in 100 mM cyclic tetrasaccharide showed transient surface opacity on the initial phase of incubation up to 5 days and then became transparent. In conclusion, cyclic tetrasaccharide delays the development of lens opacity in vitro. Cyclic tetrasaccharide might be used as a cataract-delaying agent.