Cryogenic preservation of rat polymorphonuclear leukocytes.

Rat polymorphonuclear leukocytes (PMNs) were frozen to --196 degrees C, thawed, and tested for functional viability using a variety of criteria, which included: qualitative and quantitative nitroblue tetrazolium assays, fluorometric membrane integrity assays, chemotactic assays, and bactericidal assay. Using these criteria, the survival of rat PMNs obtained from a glycogen-induced peritoneal wash averaged approximately 70% after thawing. The survival of PMNs obtained from rat peripheral blood was greater than 95%. Maximal survival for cryopreservation of these cells frozen in the presence of 10% dimethyl sulfoxide and 5% hydroxyethyl starch was obtained when the cells were cooled at approximately 10 degrees C/min.