| q Existence of nerve distribution of bone tissue has been confirmed, but the function of nerve of bone tissue is still in its infancy. In recent years, research has shown that the nervous system indeed involved in bone metabolism and the physiological and pathological processes. The role of the nervous system in bone is not clear at present.In the textbooks on the issue of bone innervation is very little and the role of the nervous system are rarely mentioned in discussion of various physiological and pathological processes of bone. A number of clinical phenomena, such as Charcot osteoarthropathy, heterotopic ossification, aseptic loosening after replacement, osteoporosis and obesity-related increased bone density, have been found to have signs of nervous system involvement. These indications prompted us, nervous system not only involved in bone metabolism and the physiological and pathological processes, but also it may be the primary regulator. Bone remodeling is the most important physiological processes of bone tissue.Bone remodeling process is the"executant"leading to changes in bone structure during the pathophysiological process. The driving force behind the process of bone remodeling must be response to a variety of physiological stimuli, such as injury stimulation, stress stimulation. In the past, we only know that stress stimulation could lead to adaptive changes in bone structure, but its mechanism is not clear. There are many hypotheses, such as micro-damage hypothesis. This hypothesis is doubtful, because it ignores the special nature of the organism. The fact that the process of bone remodeling is so precise and perfect shows they must be in the fine-control. There must be a complex control system. The existence of a complex neural network in bone tissue has been confirmed, and a variety of neuropeptides have been found to exist in it. It was found that neuropeptides and bone reconstruction process are closely linked. In a variety of neuropeptides, calcitonin gene-related peptide (CGRP) causes great concern. CGRP exists in the sensory nerve, its synthesis and release is controlled by the nervous system.CGRP is known to have the closest relationship to bone remodeling. CGRPS is the most widely distributed neuropeptide in bone tissue.It is mainly distributed in active site of bone metabolism. Animal experiments in vitro confirmed that CGRP may be directly or indirectly regulate osteoblast and osteoclast differentiation and activity. CGRP can promote bone formation and inhibit bone resorption. CGRP involved in the regulation of bone growth, repair and bone remodeling. Bone remodeling is regulated by CGRP immunoreactive nerve fibers. CGRP act on the CGRP receptor on osteoblasts and osteoclasts. At present, there are two different views of effects of CGRP on bone remodeling in vivio, one view is that CGRP promote bone formation, another view is that CGRP in vivo does not have a role in the promotion of bone formation. The two sides have their own evidence.By implanting shape memory alloy into the rabbit tibial, Authors build a bone remodeling model of rabbit tibial shaft under the action of bending stresses. The shape memory alloy films implanted in rabbit tibia bone produce a that stress stimulation could lead to adaptive changes in bone structure, but its mechanism is not clear. There are many hypotheses, such as micro-damage hypothesis. This hypothesis is doubtful, because it ignores the special nature of the organism. The fact that the process of bone remodeling is so precise and perfect shows they must be in the fine-control. There must be a complex control system. The existence of a complex neural network in bone tissue has been confirmed, and a variety of neuropeptides have been found to exist in it. It was found that neuropeptides and bone reconstruction process are closely linked. In a variety of neuropeptides, calcitonin gene-related peptide (CGRP) causes great concern. CGRP exists in the sensory nerve, its synthesis and release is controlled by the nervous system.CGRP is known to have the closest relationship to bone remodeling. CGRPS is the most widely distributed neuropeptide in bone tissue.It is mainly distributed in active site of bone metabolism. Animal experiments in vitro confirmed that CGRP may be directly or indirectly regulate osteoblast and osteoclast differentiation and activity. CGRP can promote bone formation and inhibit bone resorption. CGRP involved in the regulation of bone growth, repair and bone remodeling. Bone remodeling is regulated by CGRP immunoreactive nerve fibers. CGRP act on the CGRP receptor on osteoblasts and osteoclasts. At present, there are two different views of effects of CGRP on bone remodeling in vivio, one view is that CGRP promote bone formation, another view is that CGRP in vivo does not have a role in the promotion of bone formation. The two sides have their own evidence.By implanting shape memory alloy into the rabbit tibial, Authors build a bone remodeling model of rabbit tibial shaft under the action of bending stresses. The shape memory alloy films implanted in rabbit tibia bone produce a to the change of cortical thickness. The more obvious change of cortical thickness, the more CGRP immunoreactive nerve fibers can be found in it. So, we have reason to speculate that Nervous system involved in the process of bone remodeling. At the same time, this study has deepened our understanding of the process of bone remodeling, and also allows us has a new understanding to WOLLF law. We have established a bone remodeling model of rabbit tibia. Through this model, we have studied the relationship between the bone remodeling and the expression of CGRP. Our research has shown that CGRP expression, in vivo, was significantly positively correlated to bone remodeling. Furthermore, research also shows that nervous system involved in regulating bone remodeling. The uncover of the role of nervous system in bone will deepen, or even change, people's understanding of the pathogenesis of some bone diseases and maybe provide a new way for the treatment of these bone diseases. The innovation of our research is:â‘ successfully established a long-term bone remodeling model of rabbit tibia under bending stress, and found the volume of bone formation was significantly positively related to the stress during bone remodeling process.â‘¡confirmed bone volume was significantly positively related to the expression of CGRP in bone tissue in rabbit tibial cortical bone remodeling process.â‘¢indicated CGRP-positive nerve fibers is an important medium between the nervous system and bone remodeling. |
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