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Abstract Background Increasing evidence shows the pivotal significance of miRNAs in the pathogenesis of osteoporosis. miR-381-3p has been identified as an inhibitor of osteogenesis. This study explored the role and mechanism of miR-381-3p in postmenopausal osteoporosis (PMOP), the most common type of osteoporosis. Methods Bilateral ovariectomy (OVX) rat model was established and miR-381-3p antagomir was administrated through the tail vein in vivo. The pathological changes in rats were assessed through the evaluation of serum bone turnover markers (BALP, PINP, and CTX-1), hematoxylin and eosin (H&E) staining, as well as the expression of osteoblast differentiation biomarkers. Moreover, isolated bone marrow mesenchymal stem cells from OVX-induced rats (OVX-BMMSCs) were utilized to explore the impact of miR-381-3p on osteoblast differentiation. In addition, the target gene and downstream pathway of miR-381-3p were further investigated both in vivo and in vitro. Results miR-381-3p expression was elevated, whereas KLF5 was suppressed in OVX rats. miR-381-3p antagomir decreased serum levels of bone turnover markers, improved trabecular separation, promoted osteoblast differentiation biomarker expression in OVX rats. ALP activity and mineralization were suppressed, and levels of osteoblast differentiation biomarkers were impeded after miR-381-3p overexpression during osteoblast differentiation of OVX-BMMSCs. While contrasting results were found after inhibition of miR-381-3p. miR-381-3p targets KLF5, negatively affecting its expression as well as its downstream Wnt/β-catenin pathway, both in vivo and in vitro. Silencing of KLF5 restored Wnt/β-catenin activation induced by miR-381-3p antagomir. Conclusion miR-381-3p aggravates PMOP by inhibiting osteogenic differentiation through targeting KLF5/Wnt/β-catenin pathway. miR-381-3p appears to be a promising candidate for therapeutic intervention in PMOP.

Abstract Background The minimally invasive approach for the treatment of displaced scapular neck or body fractures has the advantages of less trauma and minimal muscle dissection. In clinical practice, the minimally invasive approach combined with an anatomical locking plate has been used to treat scapular body fractures. In addition, we have made minor modifications to the minimally invasive approach. However, the biomechanical study about the approach combined with an anatomical locking plate in treating scapular body fractures was limited. Methods Finite element analysis (FEA) was used to conduct the biomechanical comparison between the anatomical locking plate (AP model) and reconstructive plate (RP model) in the treatment of scapular body fractures through the modified minimally invasive approach. A healthy male volunteer with no history of scapula or systemic diseases was recruited. High-resolution computed tomography images of his right scapula were obtained. Two scapula models were constructed and analyzed by the software of Mimics 21.0, Geomagic Wrap 2021, SolidWorks 2021, and ANSYS Workbench 2022, respectively. Results Through static structural analysis, in terms of equivalent von Mises stress, equivalent elastic strain, and total deformation, the AP model exhibited superior safety characteristics, enhanced flexibility, and anticipated stability compared with the RP model. This was evidenced by lower maximum stress, lower maximum strain and displacement. Conclusion The minimally invasive approach combined with an anatomical locking plate for scapular body fractures had better biomechanical stability. The study provided a biomechanical basis to guide the clinical treatment of scapular body fractures.

Abstract Spinal cord injury (SCI) is a serious traumatic disease of the central nervous system and leads to incomplete or complete loss of the body’s autonomous motor and sensory functions, seriously endangering human health. Recently, exosomes have been proposed as important substances in cell-to-cell interactions. Mesenchymal stem cell (MSC)-derived exosomes exert good therapeutic effects and play a crucial role in neurological damage repair. However, the detailed mechanisms underlying their effects remain unknown. Herein, we found that compared to SCI rats, those subjected to umbilical cord MSC (UC-MSC)-derived exosomes injection showed an improved motor ability. Nevertheless, the transcriptome of BV2 microglia in different treatment groups indicated that the action pathway of exosomes might be the NF-κB/MAPK pathway. Additionally, exosomes from UC-MSCs could inhibit P38, JNK, ERK, and P65 phosphorylation in BV2 microglia and SCI rat tissues. Moreover, exosomes could inhibit apoptosis and inflammatory reaction and reactive oxygen species (ROS) production of BV2 microglia in vitro and in vivo. In conclusion, UC-MSCs-derived exosomes might protect SCI in rats by inhibiting inflammatory response via the NF-κB/MAPK signaling pathway, representing novel treatment targets or approaches for SCI.

Abstract Background N6-methyl adenosine (m6A) is the most common reversible mRNA modification in eukaryotes implicated in key roles in various biological processes. The purpose of our analysis was to examine the association of ankylosing spondylitis (AS) with m6A methylation. Method We obtained 72 samples from the data set GSE73754, including 52 AS patients and 20 healthy people. We divided the samples into two groups: the experimental group and the control group, and then observed the differences of 26 m6A related genes in the two groups. We also analyzed the correlation between different m6A genes. We used a random forest tree model to screen seven m6A signature genes associated with AS to evaluate its prevalence. Next, the samples were classified according to the m6a content and differential genes. Immune analysis, gene ontology, and KEGG enrichment analyses were performed. Finally, we scored each sample with m6a and analyzed the relationship between different samples and inflammation-related factors. Results and conclusion In conclusion, we screened out AS-related genes and the nomogram showed that they were negatively correlated with the incidence of AS. And we found that AS may have some relationship with immunity. Our analysis results could provide further insights into the treatment of AS.

Abstract Background Due to the lack of postoperative reporting outcomes and bio-mechanical studies, an optimal management of scapular fractures has not been well-established in clinical treatment, even though there are many options available. This study aimed to compare the stability of the new titanium anatomic and traditional titanium reconstructive plates for extra-articular scapular fractures through finite element analysis. Methods Two models of scapular assembly were constructed, including one anatomic plate (AP model) and one reconstructive plate (RP model). After meshing, material parameter, and boundary condition settings, we applied four loading conditions to simulate forces acting on the scapula and osteosynthesis material. To evaluate the bio-mechanical properties, the equivalent von Mises stress, equivalent elastic strain, and total deformation were investigated. Result The stress and strain distribution of model AP has better performance than model RP, with more uniform and lower values. The maximum stress value of the scapula in model AP is smaller than that of the scapula in model RP (102.83 MPa vs. 166.71 MPa). The maximum stress of the anatomic plate is half that of the reconstructive plate (218.34 MPa vs. 416.01 MPa). The maximum strain of the scapula in model AP is smaller than that of the scapula in model RP (0.0071 vs. 0.0106). The maximum strain of the anatomic plate is half that of the reconstructive plate (0.0019 vs. 0.0037). The maximum displacement of each model is all at the acromion, with a similar value (2.2947 mm vs. 1.8308 mm). Conclusions With sufficient bio-mechanical stability, the anatomic plate to support scapular fracture fragments was superior to that of the reconstructive plate.

Abstract Background Low-intensity pulsed ultrasound (LIPUS) is a common adjunct used to promote bone healing for fresh fractures and non-unions, but its efficacy for bone distraction osteogenesis remains uncertain. This study aims to determine whether LIPUS can effectively and safely reduce the associated treatment time for patients undergoing distraction osteogenesis. Methods MEDLINE, EMBASE, and the Cochrane Library were searched until May 1, 2018, without language restriction. Studies should be randomized controlled trials (RCTs) or quasi-RCTs of LIPUS compared with sham devices or no devices in patients who undergo distraction osteogenesis. The primary outcome was the treatment time. The secondary outcome was the risk of complications. Treatment effects were assessed using mean differences, standardized mean differences, or risk ratios using a random-effects model. The Cochrane risk-of-bias tool was used to assess the risk of bias. The I 2 statistic was used to assess the heterogeneity. The GRADE system was used to evaluate the evidence quality. Results A total of 7 trials with 172 patients were included. The pooled results suggested that during the process of distraction osteogenesis, LIPUS therapy did not show a statistically significant reduction in the treatment time (mean difference, − 8.75 days/cm; 95% CI, − 20.68 to 3.18 days/cm; P = 0.15; I 2 = 72%) or in the risk of complications (risk ratio, 0.90 in favor of LIPUS; 95% CI, 0.65 to 1.24; I 2 = 0%). Also, LIPUS therapy did not show a significant effect on the radiological gap fill area (standardized mean difference, 0.48 in favor of control; 95%CI, − 1.49 to 0.52; I 2 = 0%), the histological gap fill length (standardized mean difference, 0.76 in favor of control; 95%CI, − 1.78 to 0.27; I 2 = 0%), or the bone density increase (standardized mean difference, 0.43 in favor of LIPUS; 95%CI, − 0.02 to 0.88; I 2 = 0%). Conclusions Among patients undergoing distraction osteogenesis, neither the treatment time nor the risk of complications could be reduced by LIPUS therapy. The currently available evidence is insufficient to support the routine use of this intervention in clinical practice. Trial registration CRD 42017073596