A simplified method of preparation of mammalian intestine samples for scanning electron microscopy

Abstract

Due to strong tissue hydration and complex architecture of the mucous membrane, appropriate preparation of inhomogeneous gastrointestinal tissues, especially from the intestine, for scanning electron microscopy is still a challenge and requires constant improvement of preparation techniques. In this article, we describe a simplified method of preparation of small intestinal mucosa tissues for observations in a scanning electron microscope. We emphasized the most important points in the preparation process that, when ignored, may result in formation of numerous artifacts and the inability to analyze the samples reliably. The developed technique facilitates proper animal tissue sampling in the field conditions, reducing the time of tissue collection and sample preparation as well as the total process costs. The fixative of choice, that is, buffered formalin, fixes, and stiffens the processed tissues properly, which is especially important in preservation of long, highly hydrated intestinal villi without shrinkage artifacts. The method described has been successfully used in comparative studies of the development of small intestines in mammals (pigs, mice, rats), reptiles, and birds (hens).