Differential effects of tissue processing on tetraploid neurons as compared with diploid neurons and glia

Abstract

Volumes of nucleus, nucleolus and cytoplasm of tetraploid neurons were compared with volumes of the same components in diploid neurons and glia in two types of histologic preparations of rat cerebellum. One preparation utilized rapid freezing of tissue and tissue processing including phase-microscopic examination without tissue thawing. The other preparation utilized ethanol-acetic acid fixation and paraffin embedding (routine tissue processing). Diploid glial and neuronal nuclei show shrink-age of about 50% with routine processing as compared with rapid freezing. The tetraploid Purkinje cell nuclei, however, show no shrinkage with routine tissue processing as compared with rapid freezing. It is concluded that volume measurements on nervous tissue are difficult to interpret in the face of this differential shrinkage of tissue elements. The possible biologic meaning of differential shrinkage of tetraploid as compared with diploid nuclei is discussed.