BackgroundAlthough it has been reported that hypoxic exposure can attenuate hypertension, heart disease, diabetes, and some other diseases, effects of hypoxia on osteoporosis are still unknown.Material/MethodsThe current study investigated whether short-term hypoxic exposure (in comparison with normoxic conditions) affects bone metabolism in normal or ovariectomized (OVX) adult female rats in an vivo study. Micro-computed tomography bone volume/structural analyses, histological examination, and serum bone turnover biochemical assays were used. In addition, the expressions of some associated major regulatory molecules were measured in osteoblastic cultures.ResultsWhile the 14-day hypoxic exposure did not change the bone-remodeling process in normal adult female rats, it decreased bone volume, osteoclast density, and serum bone formation marker (alkaline phosphatase) level, but increased osteoclast density and serum bone resorption marker (C-telopeptide of collagen) level in OVX rats. The bone marrow adipocyte number and serum fatty acid binding protein-4 level were increased in OVX-hypoxic rats compared with OVX-normoxic rats. Consistently, in human MG-63 osteoblastic cultures, the hypoxic condition suppressed protein expression of osteogenic transcriptional factors Runx2 and osterix, elevated protein expression of osteoclastogenic cytokine receptor activator of nuclear factor kappa-B ligand, but reduced that of osteoclastogenic inhibitor osteoprotegerin.ConclusionsOur results suggest that, although no change occurred in the bone-remodeling process in normal adult female rats after hypoxic exposure, under the estrogen-deficient osteoporotic condition, the hypoxic condition can alter the bone microenvironment so that it may further impair osteoblastic differentiation and enhance osteoclastic formation, and thus reduce bone formation, enhance bone resorption, and accelerate bone loss.

Long noncoding RNAs (lncRNAs) have been wildly demonstrated to participate in the osteosarcoma tumorigenesis. ZFAS1 is a novel identified lncRNA, however, its role in osteosarcoma is still unclear. In present study, we utilize lncRNA microarray assay to screen the lncRNA expression profile in osteosarcoma tissue, and investigate the regulatory function of ZFAS1 in osteosarcoma. LncRNA microarray assay revealed that lncRNA ZFAS1 was significantly up-regulated in 3 pairs of osteosarcoma and adjacent non-tumor tissue, which was confirmed by RT-PCR. Furthermore, in 53 pairs of osteosarcoma patient samples, the up-regulated expression of ZFAS1 was closely related to poor prognosis. In vitro, loss-of-function experiments showed that ZFAS1 knockdown significantly suppressed the proliferation, induced cycle arrest at G0/G1 phase and enhance apoptosis. In vivo, ZFAS1 knockdown inhibited the tumor growth. Bioinformatics online programs predicted that ZFAS1 sponge miR-486 at 3’-UTR with complementary binding sites, which was validated using luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Rescue experiments confirmed that miR-486 could reverse the functions of ZFAS1 on osteosarcoma genesis. In conclusion, our results demonstrate that ZFAS1 act as competing endogenous RNA (ceRNA) for miR-486, and act as oncogene in osteosarcoma tumorigenesis, and discover the functional regulatory pathway of ZFAS1 sponging miR-486.

Objective: Maisonneuve fracture is a special type of injury which are rare in clinic. The manifestation of such fractures is variable. The aim of this study is to describe the pathoanatomical features of typical Maisonneuve fracture on the basis of radiographs, computed tomography (CT) scans, magnetic resonance imaging (MRI), and intraoperative exploration findings, and to investigate the injury mechanism of this variety. Methods: The data of 41 patients with Maisonneuve fracture from April 2014 to September 2019 were retrospectively analyzed. There were 32 males and nine females, the average age was 37.9 years (range, 18 to 61 years), the fractures occurred on the left side in 20 patients and on the right side in 21 patients. The cause of injuries were traffic accident in five patients, sprain injury in 20 patients, and falling injury from height in 16 patients. All patients underwent posteroanterior and lateral X-ray examinations of the ankle and calf. CT scan of the ankle was performed in 38 patients, including three-dimensional reconstruction in 33 patients. MRI examination of the ankle and calf was performed in 28 and five patients, respectively. Forty patients were treated with open reduction and internal fixation. The features of proximal fibular fracture, injuries of the medial and posterior structures of the ankle, injuries of the anterior inferior tibiofibular ligament and the interosseous membrane were recorded and analyzed. Results: Forty-one patients had proximal one-third fractures of the fibula including six patients with fracture involving the fibular neck, 30 with proximal one-third fractures of the fibular shaft, and five with proximal-medial one-third junction fracture of the fibular shaft. Thirty-five patients (35/41, 85.37%) with injury of posterior structures, 34 patients had posterior malleolar fracture (34/41, 82.93%), and one patient had posterior inferior tibiofibular ligament rupture (1/41, 2.44%). There were 20 patients with type I fracture, four patients with type II fracture, and 10 patients with type III fracture according to the Haraguchi classification of posterior malleolus fracture. The fracture of the medial malleolus was in 30 patients (30/41, 73.17%), rupture of the deltoid ligament was in 10 patients (10/41, 24.39%), and medial structures intact were in one patient (1/41, 2.44%). All 41 patients had injury of the anterior inferior tibiofibular ligament. Conclusions: Maisonneuve fracture is characterized by fractures of the proximal fibula and the complete rupture of the anterior inferior tibiofibular ligament. Pronation-external rotation is the main injury mechanism. The manifestations of typical Maisonneuve fracture including that the fibular fracture located in proximal one-third diaphysis and the fracture line was from anterosuperior to posteroinferior.

Our method of 3-D model construction provided precise measurements of the structural features of the talus. The talar dimensions in our Chinese study cohort differ from those previously reported for people of different ethnic groups. Our models should provide accurate reference data for constructing models based on CT images for the assessment and treatment of talar injuries in Chinese patients.