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Background interbody fusion in the surgical treatment of spinal disorders is one of the most commonly used surgical methods, the success or failure of a stake in the success or failure of fusion of the lumbar spine surgery. Autologous bone graft fusion is the fusion of the gold standard. Nearly half a million patients because the spine or fractures through fusion surgery to relieve severe low back pain or fracture nonunion renovated to promote healing and receiving treatment in the United States each year. Surgery, spine surgery accounted for 1/2. During various spinal fusion surgery or obvious fracture of the bone defect treatment, often surgery is required bone grafting. The face of all kinds of options for autologous bone, allograft bone, DBM graft material, whether for the patient to choose what kind of graft material the clinical spine surgeons have been facing a confusion. Use of autologous bone graft fusion has been the majority of scholars accepted, although there are a variety of allogeneic bone, but always can not be completely replaced by autologous bone, autologous bone graft has many advantages (such as low-cost, no immune rejection, etc.), autologous bone graft also brought a lot of problems, such as autogenous bone graft fusion rate not in increasing year by year, which can lead to the degeneration of the adjacent segment instability, pseudarthrosis. How to improve spinal fusion rate has become a hot research. Parathyroid hormone (parathyroid hormone, PTH), a hormone secreted by the parathyroid major regulator of the body's calcium and phosphorus metabolism and bone metabolism. A large number of studies have confirmed that parathyroid hormone and its fragments and analogues directly stimulate bone growth and a strong role, especially in the spine trabecular bone in patients with osteoporosis. Fracture repair of various age groups and astronaut bone loss caused by weightlessness are showing the desired effect. The decline in the incidence rate of vertebral and non vertebral fractures. PTH analogs developed abroad, there are two E. coli expression system successfully developed rhPTH (1-34), respectively, for the United States Lilly and Allelix Escherichia coli expression system using protease missing, and natural PTH sequence transformation successfully developed rhPTH (1-84). PTH analogs the Teli Pa skin (teriparatide) is developed by Eli Lilly and Company (Lilly) was listed in the United States, Austria, Denmark, Finland, Germany, Greece, Iceland, Ireland, the Netherlands, Norway, Portugal, Switzerland, 2002 have been listed in the UK and Australia, and in 2003 and 2004, is currently the only drug to treat osteoporosis. Teriparatide human parathyroid hormone analogues to be mediated by cell surface receptors specific high affinity binding, increase osteoblast activity and quantity and to promote bone formation, and applied to osteoporosis and prevention of osteoporotic fracture treatment with natural parathyroid hormone (PTH), which has the N-terminal 34 amino acid sequence of the same structure, it can be combined with the PTH-1 receptor, and to play a physiological role of PTH on bone and kidney; while there is no adverse effect on the C-terminal peptide of bone metabolism. Studies have shown that the drug can promote bone formation and increase bone density and reduce the risk of fractures, osteoporosis drug combination with other treatments can enhance the efficacy. The observed changes in bone turnover markers 6 months, 1 year after stopping the drug. The study found that reflect bone formation indicators such as serum alkaline phosphatase (ALP), collagen type I N-terminal propeptide (PNP) in the teriparatide group increased significantly (P lt; 0.001), and risedronate group was significantly decreased (P lt; 0.001); reflect bone resorption with serum type I collagen C-telopeptide (CTX) in the teriparatide group also increased, while the decline in the risedronate group, suggesting that teriparatide unique promote bone formation and bone resorption dual role. The routine primary osteoporosis drugs such as bisphosphonates, calcitonin, estrogens, and its mechanism of action by inhibiting osteoclast activity to achieve the effect of treatment of osteoporosis, teriparatide the only think that promote bone anabolic drugs. Alone or in combination teriparatide can increase bone density, improved bone microarchitecture, reduce the risk of fractures. Lilly's results of Phase III clinical trials in 1637 suffering from osteoporosis - related fractures in postmenopausal women, rhPTH (1-34) with a significant reduction in patients suffering from moderate or severe vertebral fracture risk rate and the risk of non-vertebral fractures rate noticeable effect. PTH for osteoporosis rat and human, not only to stimulate bone formation, but also to increase bone mass and strength. The primate bone remodeling and structure similar to human bone, primates have been gradually applied to the experiment, the study confirmed that six consecutive months daily subcutaneous injection of recombinant human PTH (rhPTH) (1-34), can increase spine mineral density in ovariectomized monkeys, does not affect the level of serum ionized calcium or urinary calcium excretion. This is the first approval of drugs to promote bone formation, and therefore subject to special attention. hPTH (1-34) is a bone formation drugs, and to promote the growth of new bone by increasing osteoblast cell number and (or) its vitality. Intermittent PTH strong osteogenesis application but the mechanism of action is not fully understood. Mainly the following view: inhibition of apoptosis of osteoblasts; promote into the proliferation and differentiation of osteoblast cells and osteoblasts, this process may be related to the core binding factor; promote bone lining cells to osteoblasts transformation; regulating osteoblast autocrine and paracrine. PTH has strong osteogenic effect, there are now a lot of literature reported that small doses of hPTH (1-34) can increase the body BMD, and treatment of osteoporosis. hPTH (1-34) on spinal fusion rate reported in the literature to improve fusion rate, increase the bone mass of the fusion zone. HPTH (1-34) has been confirmed mainly by activating the PTH1R receptor, thereby activating several signal transduction pathways, including the cAMP / PKA, NonPLC / PKC and the PLC / PKC, etc.. The study proved PLC / PKC to promote the conversion of bone metabolism, stimulates bone resorption. Complex and inherently the clinical application of PTH to promote bone synthesis and promote bone resorption, how to avoid promoting bone resorption to play its role of promoting bone formation is currently one of the hot spots to study. Thus stimulate a PTH single design PTH signal selectivity analog peptide signaling pathway is an important avenue of research. G1, R19 (1-34) and G1, R19 (1-28) is a based on of hPTH alterations peptide. YangD confirmed G1, R19 (1-34) can not activate the PLC / PKC signaling pathways by PTH1R receptors activate the cAMP / PKA signaling and NonPLC / PKC signaling pathway, can increase the body BMD and promote the formation of cancellous bone, to improve its the microstructure; and confirmed intermittent small dose G1 R19 (1-34) is superior in promoting differentiation of osteoblasts and trabecular bone anabolic effect on hPTH (1-34), theoretically not stimulate PLC pathway ( studies have shown that the PLC to promote the conversion of bone metabolism, stimulates bone resorption) more reasonable. Research purposes, through the establishment of the rat spinal fusion model study of three signal selective PTH analog peptide systemic use of the rat spinal fusion and bone mass. Analysis of PTH by non-PLC signaling pathway affects the transplanted bone healing mechanism. Clarify the PTH through different signal transduction pathways autologous bone spine fusion the signal select analog PTH (1-34) to provide a theoretical basis for the clinical application of peptides in spinal surgery. Clinical promote spinal fusion experimental basis, and to lay the foundation for the next step of clinical trials and PTH-related drug design. Research method 32 purebred healthy male SD rats (animals, anesthesia and antibiotics medication by Southern Medical University Animal Center), the average weight of 220g, eight weeks weeks of age, 3% pentobarbital intraperitoneal injection of anesthesia, all animals posterolateral Road spinal fusion surgery, were randomly divided into four groups, each group of eight. G1, R19 (1-28) group - hypodermic G1, R19, (1-28) (200μg/kg), hPTH (1-34) group - hypodermic hPTH (1-34) group (15μg/kg) G1, R19 (1-34) group - subcutaneous injection G1, R19 (1-34) group (30μg/kg), control group - subcutaneous injection of an appropriate amount of saline. Housed separately particles nutritional diet, free access to water, the same lighting and ventilation conditions. Postoperative fourth day groups, respectively, using the above method to start the subscapularis District subcutaneous injection once a day, five days a week, for a total of six weeks. Six weeks after surgery techniques palpation activity of the fusion segment fused segments X-ray score fusion segments BMD and BMC Micro-CT and histological observation. Results practices palpation: G1, R19 (1-28) group, hPTH (1-34) group, G1, R19 (1-34) and control groups fusion rate reached 37.5%, respectively, 50%, 87.5% and 50%, ; the X-line rating system (\The control group (1.8750 ± 1.3562) min, (2.8333 ± 1.3101) min, (3.8750 ± 0.7546) sub-sub (2.5417 ± 1.3206), statistically significant differences between the four groups (x2 = 8.850, P = 0.031), The average rank were 10.69,16.56,24.13 and 14.63; vitro fusion segment BMD statistically significant difference between the four groups (F = 9.136, P = 0.000) from the mean value point of view, the G1, R19 (1-34) group than in the other three groups, and G1, R19 (1-28) statistically significant difference between the groups was significantly (P = 0.001), and hPTH (1-34) group (P = 0.524) and the control group (P = 1.000) The difference was not statistically significant, hPTH (1-34) and G1, R19 (1-28) group significant difference is not significant (P = 0.056), hPTH (1-34) group and the control group, the difference was not significant (P = 0.600), G1, R19 (1-28) was significantly lower than the control group statistically significant difference (P = 0.001). Vitro fusion segment BMC statistically significant difference between the four groups significantly (F = 22.353, P = 0.000), statistical test, G1, R19 (1-34) group than hPTH (1-34) group (P = 0.008 ), G1, R19 (1-28) group (P = 0.000) and the control group (P = 0.000), hPTH (1-34) group was higher (P = 0.001), hPTH (1-34) group and G1, R19 (1-28) group, the difference was not statistically significant (P = 0.430), G1, R19 (1-28) group and the control group, the difference was not statistically significant (P = 0.112); Micro-CT scan analysis of fusion zone volume, the results show that the difference among the four groups was statistically significant (x2 = 8.031, P = 0.045). G ', R19 (1-28) group, hPTH (1-34) group, G1, R19 (1-34) and control groups respectively of 290.233 ± 49.201mm3, 343.356 ± 106.742mm3 in 401.008 of ± 97.116mm3 and 339.789 ± 44.198mmm3, average rank respectively 9.13,16.75,22.13 18.00; six weeks after all samples for histological observation. G ', R19 (1-34) group and hPTH (1-34) were observed in the distribution of trabecular rules, medullary cavity completely recanalization, while the control group of trabecular bone is thicker disordered arrangement of the medullary cavity is not fully recanalization, G 'R19 (1-28) group most of the medullary cavity is not the same, a lot of unabsorbed transplanted bone fragments are also visible. Control group and G1, R19 (1-28) group G1, R19 (1-34) the group and hPTH (1-34) group also visible cartilage cells; less likely to see the chondrocytes, although you can see some of the new bone formation, but slower growth in nonunion area, large amounts of collagen fibers like tissue. Conclusion 1, intermittent subcutaneous injection G1, R19 (1-34) can increase the volume of rat posterolateral Road, spinal fusion rate and fusion zone, and more significantly than hPTH (1-34); once again confirmed the G1, R19 ( 1-34) can not activate the PLC / PKC signaling pathways by PTH1R receptors activate the cAMP / PKA signaling and NonPLC / PKC signaling pathway, increased body BMD and promote the formation of cancellous bone to improve its micro-structure. Confirmed intermittent small doses of G1 and R19 (1-34) in promoting differentiation of osteoblasts and cancellous bone to promote superior synthesis hPTH (1-34), in theory, because they do not stimulate the PLC pathway (studies have shown that PLC to promote the conversion of bone metabolism, stimulates bone resorption) is more reasonable. Provide an experimental basis for clinical selection of G1, R19 (1-34) fragment. 2, from the the practices palpation, X-ray evaluation, fusion segments BMD and BMC of MicroCT and histological observation, G1, R19 (1-28) inhibition of rat spinal fusion; This shows that inhibition NONPLC / PKC signal pathway, inhibition of bone regeneration and reconstruction, thus inhibiting the spinal fusion.
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