A cryoprotection method that facilitates cutting frozen sections of whole monkey brains for histological and histochemical processing without freezing artifact.

摘要: Cutting frozen sections of large (greater than 60 cc) blocks monkey brain using the conventional procedures infiltration with 30% sucrose as a cryoprotectant before freezing pulverized dry ice often produces unacceptable levels artifact (FA) caused by displacement tissue crystals. Experiments investigating FA utilized perfusion-fixed brains from 46 monkeys and spanned combinations cryoprotectants (glycerol, sucrose), methods (dry or -75 degrees C isopentane), fixatives (10% formalin, Karnovsky's Timm's). The effects were evaluated rating severity in whole brains. Minor appears enlarged capillaries, more serious vacuoles, both first appear midway between periphery center block. Stronger increased artifact. best method for eliminating was graded up to 20% glycerol 2% DMSO (in buffer fixative), followed rapid isopentane. Although glycerol-DMSO isopentane gave better results dry-ice freezing, only combination produced consistently excellent virtually eliminated To determine effect on rate cooling CNS tissue, thermocouples embedded an 80-cc block albumin-gelatin two methods. (-3.5 C/min) twice fast