Membrane damage occurs during the formation of intracellular ice

Current theories on both the formation of intracellular ice (IIF) and the m echanisms by which it damages cells all implicate the plasma membrane, Whil e it has been well documented that following IIF post-thaw damage to the pl asma membrane occurs, it is not known whether this damage occurs during fre ezing or thawing. By directly monitoring the diffusion of a membrane-im per meable fluorescent stain into V-79W fibroblasts, the integrity of the plasm a membrane during freezing and thawing was correlated with the incidence of IIF, While this study presents evidence that membrane damage occurs during the formation of intracellular ice in cell suspensions, single attached ce lls and confluent monolayers, we cannot conclude whether IIF is the cause o r result of membrane damage.