The innervation of the bone marrow in laboratory animals

Abstract

The nerve pattern of the bone marrow of the monkey, rabbit, rat and mouse was studied in serial sections specially stained to demonstrate myelinated and nonmyelinated nerve fibers. Features that are common to the different species studied were found in the bone marrow of the femur of the rat in a simple arrangement.A scheme is proposed based on thirteen photomicrographs demonstrating the nerve pattern of the bone marrow and the relation of the nerve fibers with the arterial tree, the sinusoids and the blood forming cells. This scheme shows that the necessary anatomical conditions exist permitting a direct influence of the nervous system on the function of the bone marrow. These conditions are the presence of myelinated nerve fibers traversing the parenchyma of the marrow, and the existence of nonmyelinated fibers ending in sphincterlike structures at the origin of the arterioles.Single myelinated nerve fibers and small bundles of both myelinated and nonmyelinated fibers lie in close contact with the endothelial wall of the sinuses during long trajects. Only the very thin endothelium of the sinuses separates the newly formed blood and the nerve fibers. An interaction between both elements is possible along these areas of contact.The function of an organ cannot be fully understood without considering also the nervous system, yet the study of the innervation of the bone marrow has long been neglected. Its study is of interest in normal morphology and physiology, and may prove to be of importance in pathology.The purpose of this paper is to present observations concerning the presence, the nature and the distribution of the nerve fibers in bone marrow of normal adult animals commonly used in the laboratory, as well as the relations between the nerve fibers and the cells of the parenchyma, the arterial vessels and the sinusoids. It is hoped that the description of the normal architecture of the bone marrow, with the nerve pattern included, may throw some light on the understanding of the mechanisms that regulate the proliferation and release of the blood cells, and also on the maintenance of homeostasis and on the adaptation of the function of the bone marrow to different stimulations. MATERIAL AND METHODSThe bone marrow of the long bones of the normal adult mouse, rat, rabbit and monkey was studied. For the demonstration of the nonmyelinated fibers, the marrow was impregnated en bloc by the silver nitrate method of Cajal after fixation and decalcification of the bone with the fluid of Castro ('25). The femur, tibia and humerus of the small animals (mice and rats), with their bone marrow inside, was embedded in paraffin and cut entirely in serial sections, 10 thick. This method permits the study of the bone marrow in relation to the bone. The marrow of the large animals (rabbit and monkey) was extracted from the bone as cylinders of approximately 15 mm in length and impregnated with the silver nitrate. Cylinders of marrow from the area of the nutrient foramen, the diaphysis and the distal epiphysis were studi...

Primary human CD34+ hematopoietic stem and progenitor cells express functionally active receptors of neuromediators

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Electrostimulation and morphologic study of the nerves to the bone marrow of the albino rat

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