An evaluation of the cryosectioning of fixed and cryoprotected rat liver

The influence of temperature and speed on cryosectioning was studied by replication of the surfaces of both the sections and the specimen blocks. At 90 mm/s and at temperatures lower than -70 degrees C, specimen block surfaces displayed fracture images similar to those encountered with standard freeze-fracturing procedures; but at a speed of 0.1 mm/s, fracture images were found only at temperatures lower than -120 degrees C. Replicas of both sides of cryosections never displayed fracture images. The discrepancy between the surface structure of cryosections and specimen blocks is discussed from the aspect of the preservation of ultrastructure of cells.