Distribution of the total and non-freezable water in rat lenses

Twenty Sprague-Dawley rats of ages from 7 days to 29 weeks were studied. The cortical and nuclear samples from rat lenses were investigated by differential scanning calorimetry (freezable water content) and thermogravimetric analysis (total water content). Both cortical and nuclear regions showed a decrease in total water content with aging. Only the nuclear parts of the rat lenses showed a statistically significant increase in the non-freezable portion of the total water with aging. The cortical parts showed a slight but statistically non-significant increase in this parameter. It is concluded that in rat lenses aging is primarily an aggregation process and syneresis does not play a significant role.