[Objective]To develop a standard closed experimental fracture model in mouse femur.[Method]A 0.45 mm stainless-steel rod was introduced into the medullary cavity and the pre-nailed femur shaft was fractured by an impact device,which resulted in a reproducible transverse fracture pattern.The fractures were examined using X-ray Micro-CT,and histological method.[Result]Transverse fractures were created in 91.67% of the experimental mice,and the fracture healing was typical secondary fracture healing.[Conclusion]The standard closed fracture model in this experiment,whose healing was typically secondary fracture healing,can be obtained easily and used in study of fracture.

BACKGROUND: Diabetes mel itus is one of the most common systemic diseases, which often leads to the changes of the jaw and other bone structure, as wel as the abnormal changes of mineral metabolism. OBJECTIVE: To observe the three-dimensional structure and histopathological changes of the mandible in type 1 diabetes mel itus mice. METHODS: The mice were randomly divided into control group and diabetes mel itus group. The diabetes mel itus group received intraperitoneal injection of 50 mg/kg streptozotocin for 5 days to establish a type 1 diabetes mel itus model, and the control group received intraperitoneal injection of citrate buffer. RESULTS AND CONCLUSION: At 3 weeks after modeling, the micro-CT technique was used to observe the three-dimensional structure of the mandibles in the two groups. The quantitative analysis on the microstructure of cancel ous bone and cortical bone showed that the bone mineral density, bone volume fraction, trabecular number and trabecular thickness of cancel ous bone in the interest region in the mandible of type 1 diabetes mel itus mice were significantly decreased when compared with that in the control group (P < 0.01, P < 0.05), while the structure model index was increased significantly (P < 0.05); the mineral density and area of cortical bone were decreased in the diabetes mel itus group (P < 0.05). Hematoxylin-eosin staining showed that the number and volume of mandibular trabeculae of type 1 diabetes mel itus mice were decreased. The results suggest that the three-dimensional structure of the cancel ous bone and cortical bone in the streptozotocin-induced type 1 diabetes mel itus mice are changed significantly, and the microstructure change of the cancel ous bone is more obvious.

AIM:To investigate COX-2 and iNOS protein contents and their interaction in vascular endothelium injury of rats with deficiency of vital energy or qi stagnation,and the prevetion and treatment of Tongxinluo.METHODS:The model of vascular endothelium injury of rats with deficiency of vital energy or qi stagnation was established by using high L-Methionine,with load-carrying swimming or being fastened respectively.Western blotting was used to analyze protein contents of COX-2 and iNOS,co-immunoprecipitation and laser confocal microscopy were used to analyze the interaction between COX-2 and iNOS.Optical microscope and electronic microscope were used to evaluate pathological changes in vascular endothelium.RESULTS:The protein contents of COX-2 and iNOS,and their interaction increased significantly in deficiency of vital energy group and qi stagnation group,in accord with injury of vascular endothelium.Compared with deficiency of vital energy group and qi stagnation group respectively,their protein contents decreased and their interaction was weakened in Tongxinluo groups.CONCLUSION:When protein contents of COX-2 and iNOS increase and their interaction enhance after vascular endothelium injury of rats with deficiency of vital energy or qi stagnation,initiate exacerbations,Tongxinluo could attenuate the alterations and protect vascular endothelium from injury.

Objective To investigate the role of hypoxia inducible factor-1α (HIF-1α) and von Hippel-Lindau (VHL) in murine endochondral ossification. Methods The knockout of HIF-1α or VHL gene in murine osteoblasts was accomplished by conditional knockout technique at 4th, 8th and 12th week, and the differences between wild-type group and knock-out group in endochondral ossification were detected by HE staining, micro-CT scanning, trabecular bone area measurement, calcium content measurement, tetracycline fluorescence labeling, Real-time PCR and Western blotting. Results After knockout of HIF-1α gene in osteoblasts, the expression of vascular endothelial growth factor ( VEGF) reduced, the rate of new bone formation stepped down, the content of calcium became less, and the trabecular bone volume decreased (P <0.05) . After knockout of VHL gene in osteoblasts, the expression of VEGF increased, the rate of new bone formation stepped up, the content of calcium became more, and the trabecular bone volume was promoted (P < 0.001). Conclusion During murine endochondral ossification, VHL/HIF-1α signal pathway promotes angiogenesis through the stimulation of VEGF expression, which subsequently accelerates osteogenesis.

Objective To analyze histomorphometrical characteristics of the bone and bone marrow tissues of the lumbar vertebrae in rabbits with fluoride treatment,and its correlation with signal intensity of MRI.Methods Forty New Zealand albino rabbits aged three months old were randomly divided into fluoride exposure of 30 cases and control of 10 cases,male and female,half each.One hundred milligrams of sodium fluoride were added to the municipal water each liter (fluoride content 100 mg/L) as drinking waterto fluorine for 180 days.Twenty-four of 30 cases with fluoride exposure had complete data (male10 casesand female14 cases).The same municipal water was used as control drinking water (fluoride content ＜ 0.9 mg/L).Eight of 10 cases with control had complete data (male andfemale in half).Twenty-four cases with fluoride treatment and complete data were classified into sensitive and resistant type according to the MRI signal intensity of the lumbar vertebra.Histomorphometrics of the vertebra and its correlation with the MRI signal intensity,and sensitivity in early diagnosis of osteofluorosis and feasibility of susceptibility to osteofluorosis detected with MRI were analyzed.Results Theratios of trabecular bone volume (BV),hematopoietic cell volume (HV) and fluid volume (FV) in bone marrow tissue to total cavernous tissue volume (TT) in group with fluoride treatment were 18.3％±2.6％,45.2％±6.0％ and 10.4％±5.7％ respectively.These were 14.5％±2.8％,36.3％±7.3％ and 6.2％±2.1％ in control group respectively.These parameters in fluoride group were significantly increased compared to control group.The ratio 26.0％± 8.0％ of adipocyte volume (AV) to TV in fluoride group was significantly lower than that 43.3％±5.6％ in control group.Two of 24 cases with fluoride exposure (8.3％,2/24) were sensitive and the remaining 22 (91.7％,22/24) were in resistance.The valuesof BV/TT,HV/TV and FV/TV were considered to be sensitive,resistant and control from large to small,while AV/TV value were opposite.A comparison resuhs of signal intensity in MRI showed that vertebra T1WI contrast to noise ratio (CNR) in the sensitive was the minimum (3.0±0.8),followed by resistance (21.3±3.8) andmaximum in the control (28.3±3.1),but CNR of FsT2WIwas opposite.There were positive associations between T1WI and AV/TV,FV/TV and BV/TV,and between FsT2WI and FV/TV and BV/ TV.There were inverse associationsbetween FsT2WI and AV/TV.Theoptimal threshold value of the vertebra T1WI CNR was 23.2 or lessin early diagnosis of skeletal fluorosis,with sensitivity of 83.3％ and specificity of 100％.FsT2WI was 5.7 or more,with sensitivity of 45.8％ and specificity of 100％.Conclusion The pathogenesis of osteofluorosis is relative to changes in bone marrow microenvironment and cells number in bone marrow tissue,and is correlated to MRI signal intensity.