A new morphological procedure for viewing microvessels: A scanning electron microscopic study of the vasculature of small intestine

Abstract

The present study details a new method for the exposure and viewing of individual microvessels located within the small intestine of rats. This procedure will selectively and consistently remove the outer muscle layers and underlying submucosa of the intestinal wall and thereby expose a variety of arterioles in their normal location within the tissue, with their normal relationship to each other undisturbed. The small intestine of the rat was initially fixed by vascular perfusion with 2.5% glutaraldehyde in 0.1 M cacodylate/HCL buffer, reinfused with heparinized whole blood, removed from the animal, and secured to a dissecting petri dish for further fixation. Subsequently, the external muscularis was dissected from the sample which exposed the submucosa. In order to remove the connective tissue elements from this layer and uncover the submucosal vasculature, the samples were first transferred to a solution of 30% potassium hydroxide for 2-5 minutes and then to a final digesting solution containing collagenase. Thereafter, the samples were routinely processed for light microscopy and for scanning (SEM) or transmission (TEM) electron microscopy. Examination of the samples revealed excellent preservation of the three-dimensional organization of the arteriolar wall with minimal membrane damage. This new technique now makes it possible to visualize the shape and position of individual smooth muscle cells along arterioles of differing size and branching order.

Three-Dimensional Architecture of Pericytes with Special Reference to Their Topographical Relationship to Microvascular Beds.

“…4). They were oriented circularly around the vessel, as has been shown in other organs (UEHARA and SUYAMA, 1978;MILLER et al, 1982;HOLLEY and FAHIM, 1983;MAGGIONI et al, 1989).…”

Intestinal microvascular adaptation during maturation of spontaneously hypertensive rats.

“…Red cell velocity was measured in first order arterioles during resting and passive conditions. Outer and inner diameters of the first-, second-, and third-order arterioles, the only arterioles with a continuous muscle coat, 17 were used to calculate the vessel wall thickness and the vessel wall cross-sectional area. The total number of first-, second-, and third-order arterioles were counted during resting and passive conditions.…”

Scanning Electron Microscopy of Tenotomized Soleus Muscles of the Rat.

“…In this study, a KOH-collagenase digestion method was used to remove the extracellular matrix of connective tissue (MILLER et al, 1982). According to the method modified by UsHIKI and IDE (1988), the tissue strips were incubated for 20-30 min in 25% KOH at 60C.…”