Distribution and property of nerve fibers in human long bone tissue.

OBJECTIVE: To observe the distribution of the nerve fibers in the bone tissue and the entry points of these fibers into the bone. METHODS: The adult tibia was used for the ground sections which were afterwards made into the slice sections by decalcification in ethylenediamine tetraacetic acid (EDTA). The ground sections were stained in silver and the slice sections were stained in silver and haematoxylin and eosin (HE) respectively. Then, the samples of the transmission electron microscope and the atomic force microscope were made and observed. RESULTS: In the human long bone tissue, many nerve fibers were distributed in the membrane, cortical bone, cancellous bone and marrow. The nerve fibers entered the bone from the nutrient foramen, and passed through the nutrient canal, Haversian's canal and Volkmann's canal, and finally into the bone marrow. In the nutrient canal, the nerve fibers, mainly the medullary nerve fibers, followed the blood vessel into the bone. In the cortical bone, the nerve fibers also followed the blood vessels and were mainly distributed along Haversian's canal and Volkmann's canal. In the bone trabecular and bone marrow, there were many nerve fiber endings arranged around the blood vessels, mainly around the tunica media of medium-size arteries in the marrow and around capillary blood vessels, and a few scattered in the bone marrow. There were sporadic nerve endings in epiphyseal plate and no nerve fibers permeated epiphysis to diaphysis. No distribution of nerve fibers could be found in cartilaginous part. CONCLUSIONS: There are many nerve fibers in bone and the nerve passageway is nutrient foramen, Volkman's canal, Haversian's canal and bone marrow.

[Effects of acupuncture on the expression of brain-derived neurotrophic factor in the ovariectomized rat fracture model].

OBJECTIVE: To observe the effect of acupuncture on fracture in the ovariectomized rat and the mechanism. METHODS: Sixty SD female rats were randomly divided into 4 groups: normal group (group A), model group (group B), acupuncture group (group C) and Nilestriol group (group D). In all the groups, except the group A which received sham operation, the rats were overiectomized for preparing the osteoporosis model. Three months after the ovariectomy, the left femurs of the rats were closely fractured. Then, the group A and B were treated with oral administration of normal saline solution, 3 mL, weekly. The rats in the group C were treated daily with acupuncture at "Huantiao"(GB 30), "Housanli" (ST 36), "Yanglingquan"(GB 34) and "Weizhong"(BL 40) on the left hind legs; the rats in the group D were given orally Nilestriol solution (0.2 mg/mL) in a dose of 0.6 mL/100 g body weight, weekly. At the 7th, 14th, 21st and 28th days, some rats were sacrificed and their fractural callus and blood samples were taken for histological examinations and immunohistochemical examination of brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB). RESULTS: HE stained callus slides observed by optical microscope showed that the process of fracture healing in the group A, C, D was faster than that in the group B. Positive immuno-stalning of BDNF and TrkB could be seen in the all groups, mainly on the 7 and 14 days after the fracture. The expression levels from high to low in turn were group A, C, D and B. CONCLUSION: Expressions of BDNF and TrkB in callus of osteoporotic fracture were less than that of the normal fracture; acupuncture can elevate the expression levels and accelerate the process of fracture healing.