A two-step technique for the cryopreservation of normal mouse mammary tissue

Dimethylsulfoxide is used as a cryoprotectant for the preservation of mammary tissue to be used in primary cell culture. The method involves a two-step process that reduces the sample temperature to −20° C for a short-time, which is followed by storage at −90° C or immersion into liquid nitrogen. Comparison between fresh and frozen-thawed tissue was made by the cells' ability to grow inside collagen gel in response to various hormones and growth factors. Growth of frozen-thawed and collagenase-digested tissue achieved 70 to 90% the DNA values of their nonfrozen counterparts.