Imai S, Tokunaga Y, Maeda T, Kikkawa M, Hukuda S
Department of Anatomy, Shiga University of Medical Science, Otsu, Japan.
J Orthop Res. 1997 Jan;15(1):133-40. doi: 10.1002/jor.1100150120.
The presence of nerve fibers in bone marrow has been noted by various investigators, and recent developments in immunohistochemistry have enabled differential localization of the intramedullary nerve fibers. Much interest has been devoted to the efferent activities of the afferent fibers, which probably act on the target tissues by secreting a variety of neurotransmitters. The present study aimed to further characterize intramedullary substance P, calcitonin gene-related peptide, and tyrosine hydroxylase-immunoreactive nerve fibers of the rat lower limb by comparing those of the knee, ankle, and tarsal joints. The ultrastructural details of intramedullary calcitonin gene-related peptide-immunoreactive axons were also investigated to provide a morphological basis for their possible efferent actions. Intramedullary calcitonin gene-related peptide and substance P-immunoreactive fibers in the proximal tibia and the knee joint were found to be as reported earlier, but the marrow of the distal metaphysis was also noted to be richly innervated, and the tarsal joints displayed dense innervation at the subchondral regions that underlie the joint cartilage. The articular and intramedullary innervations that function for joint protection might participate in characteristic clinical features of joint damage secondary to the neuropathies. Ultrastructurally, the intramedullary calcitonin gene-related peptide-immunoreactive axons were minimally engulfed by the Schwann cell, and naked intramedullary calcitonin gene-related peptide-immunoreactive axons were noted along an extraordinarily long extension, suggesting much efferent activity.
多位研究者已注意到骨髓中存在神经纤维，免疫组织化学的最新进展使得能够对骨髓内神经纤维进行差异定位。人们对传入纤维的传出活动投入了大量关注，这些传入纤维可能通过分泌多种神经递质作用于靶组织。本研究旨在通过比较大鼠下肢膝关节、踝关节和跗关节的情况，进一步描述骨髓内P物质、降钙素基因相关肽和酪氨酸羟化酶免疫反应性神经纤维的特征。还研究了骨髓内降钙素基因相关肽免疫反应性轴突的超微结构细节，为其可能的传出作用提供形态学依据。胫骨近端和膝关节内的降钙素基因相关肽和P物质免疫反应性纤维与先前报道的一致，但也注意到干骺端远端的骨髓神经支配丰富，跗关节在关节软骨下方的软骨下区域显示出密集的神经支配。具有关节保护功能的关节和骨髓神经支配可能参与了神经病变继发关节损伤的特征性临床症状。在超微结构上，骨髓内降钙素基因相关肽免疫反应性轴突极少被施万细胞吞噬，并且沿着非常长的延伸段可观察到裸露的骨髓内降钙素基因相关肽免疫反应性轴突，提示有大量传出活动。
