Freeze-fracture replication technique of human skin

The freeze-fracture replication technique represents one of the most advanced methods for studying the ultrastructure of biological tissues and has given a new dimension to the ultrastructure research. This technique makes it possible to obtain a cast of a fracture surface of frozen preparations. Apart from allowing samples to be examined without being dehydrated, i.e. under conditions very close to those of living state, it has proved especially useful for the analysis of many tissue functions concerned with membrane activity and exchanges between cells and their disturbance in specific disease conditions. Even through good quality replicas had already been obtained back in 1961 (Moor et al. 1961), only after 1970, mainly thanks to the contribution made by Breathnach and his collaborators (Breathnach et al. 1972, Breathnach 1973, Breathnach et al. 1973) was the freeze-fracture replication technique successfully used in the study of the skin, since this tissue had proved especially difficult to process. In this review paper, technical principles will be summarized and the most important findings so far obtained in the study of normal and pathologic skin will be illustrated.