Investigation of the Origin of the Crystal Containing Cell in the Caecal Epithelium of the Mouse

Abstract

The crystal containing cell has been found in portions of the large and small intestine of the mouse. The cells are usually located at the basal aspect of the epithelium and contain intracytoplasmic inclusions which demonstrate a 60 A lamellar periodicity (Fig. 1) when the plane of sectioning is perpendicular to the crystal lattice. The purpose of this study is to determine if the crystal containing cells are of true epithelial origin or if they originate from a migratory cell type which enters the epithelium from the lamina propria and then differentiates.12 mice were administered intraperitoneal injections of actinomycin D in the following divisions: Group I, 23 ug actinomycin D during a 24 hour period; Group II, 33 ug during 48 hours; Group III, 40 ug over 52 hours; and Group IV, 63 ug over 72 hours. Examination of the caecal epithelia with the electron microscope revealed an increase in the number of crystal containing cells in the treated animals (Fig. 3) over the controls which were injected with corresponding amounts of physiological saline. Control epithelia have crystal cells in about 1-2% of the total cell population, whereas the treated mice epithelia have crystal cells in approximately 20%, or more of the total cells. A large number of migratory cells may have invaded the intestine in response to the peritoneal inflammation established during actinomycin D administration. The increased number of crystal cells in treated mice probably developed from the increased migratory cell population. Since low levels of actinomycin inhibit mitoses in mammalian cell lines, the increase in the number of crystal containing cells in the epithelium could not have been from divisions of the pre-existing cells originally present in the epithelium.