Histologic Effects of a Cholesterol-Free Diet on Adult White Rats.

Abstract

A series of white rats was raised upon a cholesterol-free diet over a period of 3 generations since the question had arisen as to whether or not cholesterol was synthesized in these rats in the absence of sterols. The chemical end of the research was conducted by Knudson and Randles 1 and the experimental evidence ascertained seemed to justify their conclusion that this chemical was, to a certain extent, built up by the rat body. 2 At the conclusion of their experiments, the rats were killed and the tissues fixed in Zenker, Bouin, Meves, and formalin, and stained with a variety of the usual laboratory stains, chief among which was a combination of hematoxylin and Mercurochrome-220 Soluble (Hynson, Westcott and Dunning, Baltimore, Md.).

These rats of the third generation were weak, small, and undernourished, and lived only from 11 to 17 weeks after birth, i. e., from 7 to 13 weeks after weaning. At the time of weaning they weighed from 26.0 to 30.0 gm., and at the time of death from 74.0 to 80.0 gm.

There was no evidence at the time of autopsy of either inflammation or degeneration in any of the body tissues. All of the body organs were reduced in size and in weight but preserved a fair normal proportion to the mass of the body in comparison to the controls.

All of the tissues and organs of the rats were studied in detail histologically. It was evident that the diminutive size of the various viscera had been attained less by a reduction in number of the individual functional units composing them, than by a decrease in the size of the cells forming these units. Hence, the tissues and organs presented the appearance of structural compactness, without a conspicuous absence of the characteristic cells ordinarily composing them.