BACKGROUND:Slow bone repair and poor bone formation quality are still problems during masquelet technique in the treatment of large segment bone defects.H-type vessels can induce osteogenesis,enhance the local angiogenesis and osteogenesis coupling,and promote bone repair.However,there are few reports on the role of H-type blood vessels in the bone induced membrane.OBJECTIVE:To construct a large segment bone defect model of SD rat tibia,observe the expression characteristics of H-type blood vessels in the bone induced membrane,then to identify the expression peak point of H-type blood vessels in the bone induced membrane and determine the optimal period of bone grafting.METHODS:Sixty SD rats were randomly divided into a control group(n=30)and a model group(n=30)by random number table method.The two groups were further divided into three subgroups at 4,6,and 8 weeks after bone cement implantation,with 10 rats in each group.A 4 mm bone defect model of the right tibia was constructed in both the control and the model groups.Polymethyl methacrylate bone cement was implanted in the model group to induce bone biomembrane formation,while bone cement was not implanted in the control group.At 4,6,and 8 weeks after bone cement implantation,6 rats were randomly selected at each time point.The bone induction membrane tissue was cut from the model group,and the non-bone soft tissue of the corresponding part was cut from the control group.The dynamic expressions of H-type blood vessels in the bone induced membrane were identified by immunofluorescence.The morphological changes of the bone induced membrane were observed by hematoxylin-eosin staining.The formation of blood vessels in the bone induced membrane was observed by angiography.The expression levels of osteoblast-specific transcription factor in the bone induced membrane were detected by immunohistochemistry.Four rats remained at each time point.In the model group,the bone induced membrane was cut open and the bone cement was removed and autologous coccyx was implanted.In the control group,autologous coccyx was implanted in the bone defect area.Micro-CT evaluation of the tibial defect was performed 8 weeks after bone grafting.RESULTS AND CONCLUSION:(1)Immunofluorescence staining showed that the expression of H-type vessels in the model group was most obvious 6 weeks after bone cement implantation,and the expression of H-type vessels in the model group at each time point after bone cement implantation was higher than that in the control group(P＜0.05).(2)Hematoxylin-eosin staining and angiography showed that the number and volume of new blood vessels at each time point after bone cement implantation in the model group were greater than those in the control group(P＜0.05).The order of the number and volume of new blood vessels in the model group was:8 weeks after bone cement implantation＞6 weeks after bone cement implantation＞4 weeks after bone cement implantation.(3)Immunohistochemical staining showed that the positive expression of osteoblast-specific transcription factors at each time point after bone cement implantation in the model group was higher than that in the control group(P＜0.05),and the positive expression of osteoblast-specific transcription factors in the model group was most obvious 6 weeks after bone cement implantation.(4)Micro-CT detection showed that the bone repair effect of the three subgroups in the model group was significantly better than that of the corresponding subgroups in the control group,and the bone repair effect of the subgroup in the model group 6 weeks after bone cement implantation was better than that of the subgroups 4 and 8 weeks after bone cement implantation.The results indicate that H-type blood vessels are dynamically expressed in the bone induced membrane and reached a peak 6 weeks after bone cement implantation.Good bone repair effects can be obtained by the bone induced membrane bone grafting 6 weeks after bone cement implantation.

BACKGROUND:Slow bone repair and poor bone formation quality are still problems during masquelet technique in the treatment of large segment bone defects.H-type vessels can induce osteogenesis,enhance the local angiogenesis and osteogenesis coupling,and promote bone repair.However,there are few reports on the role of H-type blood vessels in the bone induced membrane.OBJECTIVE:To construct a large segment bone defect model of SD rat tibia,observe the expression characteristics of H-type blood vessels in the bone induced membrane,then to identify the expression peak point of H-type blood vessels in the bone induced membrane and determine the optimal period of bone grafting.METHODS:Sixty SD rats were randomly divided into a control group(n=30)and a model group(n=30)by random number table method.The two groups were further divided into three subgroups at 4,6,and 8 weeks after bone cement implantation,with 10 rats in each group.A 4 mm bone defect model of the right tibia was constructed in both the control and the model groups.Polymethyl methacrylate bone cement was implanted in the model group to induce bone biomembrane formation,while bone cement was not implanted in the control group.At 4,6,and 8 weeks after bone cement implantation,6 rats were randomly selected at each time point.The bone induction membrane tissue was cut from the model group,and the non-bone soft tissue of the corresponding part was cut from the control group.The dynamic expressions of H-type blood vessels in the bone induced membrane were identified by immunofluorescence.The morphological changes of the bone induced membrane were observed by hematoxylin-eosin staining.The formation of blood vessels in the bone induced membrane was observed by angiography.The expression levels of osteoblast-specific transcription factor in the bone induced membrane were detected by immunohistochemistry.Four rats remained at each time point.In the model group,the bone induced membrane was cut open and the bone cement was removed and autologous coccyx was implanted.In the control group,autologous coccyx was implanted in the bone defect area.Micro-CT evaluation of the tibial defect was performed 8 weeks after bone grafting.RESULTS AND CONCLUSION:(1)Immunofluorescence staining showed that the expression of H-type vessels in the model group was most obvious 6 weeks after bone cement implantation,and the expression of H-type vessels in the model group at each time point after bone cement implantation was higher than that in the control group(P＜0.05).(2)Hematoxylin-eosin staining and angiography showed that the number and volume of new blood vessels at each time point after bone cement implantation in the model group were greater than those in the control group(P＜0.05).The order of the number and volume of new blood vessels in the model group was:8 weeks after bone cement implantation＞6 weeks after bone cement implantation＞4 weeks after bone cement implantation.(3)Immunohistochemical staining showed that the positive expression of osteoblast-specific transcription factors at each time point after bone cement implantation in the model group was higher than that in the control group(P＜0.05),and the positive expression of osteoblast-specific transcription factors in the model group was most obvious 6 weeks after bone cement implantation.(4)Micro-CT detection showed that the bone repair effect of the three subgroups in the model group was significantly better than that of the corresponding subgroups in the control group,and the bone repair effect of the subgroup in the model group 6 weeks after bone cement implantation was better than that of the subgroups 4 and 8 weeks after bone cement implantation.The results indicate that H-type blood vessels are dynamically expressed in the bone induced membrane and reached a peak 6 weeks after bone cement implantation.Good bone repair effects can be obtained by the bone induced membrane bone grafting 6 weeks after bone cement implantation.

Objective:To explore the associations of platelet parameters platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit (PCT) with the risk for stroke in people with different blood pressure levels.Methods:All the participants were from Dongfeng-Tongji cohort, including 38 295 retired employees from Dongfeng Motor Corporation at the first follow-up survey. After excluding participants with coronary heart disease, stroke, cancer, history of platelet influential drug use and those with missed data of platelet parameters or blood pressure or lost to follow-up, finally a total of 21 294 participants were included in this study. All the participants completed baseline questionnaires, physical examinations, clinical biochemical tests, and blood sample collection. Cox proportional hazard models were used to estimate the hazard ratios ( HRs) and the corresponding 95% confident intervals ( CIs) for the associations between platelet parameters and risk for stroke in people with different blood pressure levels. Results:After a mean follow-up of 8.0 years, 1 578 participants developed incident stroke [1 266 ischemic stroke (IS) cases and 312 hemorrhagic stroke (HS) cases]. Compared with the participants with PLT<188×10 9/L, those with PLT≥188×10 9/L among hypertension cases were significantly associated with higher risks for stroke and IS (stroke: HR=1.27, 95% CI: 1.12-1.44; IS: HR=1.39, 95% CI: 1.21-1.60). Among hypertension group, compared with participants with PCT<0.165%, PCT≥0.165% were significantly associated with higher risk for stroke ( HR=1.15, 95% CI: 1.01-1.30) and lower risk for HS ( HR=0.70, 95% CI: 0.53-0.93); Among non-hypertension and hypertension group, PCT ≥0.165% were significantly associated with higher risks of IS ( HR=1.27, 95% CI: 1.05-1.54; HR=1.31, 95% CI: 1.14-1.50). MPV and PDW were not significantly associated with risk for stroke. Risk for stroke increased significantly in hypertension cases with different platelet parameters levels compared with non-hypertension cases with lower levels of each platelet parameters. Conclusion:Higher levels of PLT and PCT could increase the risks for stroke and IS in middle-aged and elderly hypertension patients, and lower levels of PCT could decrease the risk for HS in hypertension patients.