[Importance of concentration factors in cryoinjury of lysosomes].

The injury degree of lysosomes isolated from the rat liver under low temperature conditions was studied with respect to nonsedimented hydrolases activities (acid RNases, DNase, phosphatase, cathepsins) taken as a biochemical criterium of lysosomal membrane stability. The lysosomal fraction was resuspended in 0.15 M NaCl solution and frozen in the liquid N2 vapours up to --30 degrees C. According to the thermographic analysis data the samples were thawed and studied at different stages of cooling. The activity of the studied hydrolases was established to increase most considerably during the water crystallization period and at the NaCl eutectic point. Hydrolytic enzymes release from lysosomes proved to be dependent on the thawing rate and NaCl concentration. The obtained data indicate to the importance of concentration factors in lysosomal membrane cryoinjury.