Biomechanical comparative study on external fixators of new configurations in the treatment of Tile C pelvic injury.

To compare the biomechanical properties of several anterior pelvic ring external fixators with two new configurations in the treatment of Tile C pelvic fractures, in order to evaluate the effectiveness of the new configurations and provide a reference for their clinical application. A finite element model of a Tile C pelvic ring injury (unilateral longitudinal sacral fracture and ipsilateral pubic fracture) was constructed. The pelvis was fixed with iliac crest external fixator (IC), anterior inferior iliac spine external fixator (AIIS), combination of IC and AIIS, combination of anterior superior iliac spine external fixator (ASIS) and AIIS, and S1 sacroiliac screw in 5 types of models. The stability indices of the anterior and posterior pelvic rings under vertical longitudinal load, left-right compression load and anterior-posterior shear load were quantified and compared. In the simulated bipedal standing position, the results of the vertical displacement of the midpoint on the upper surface of the sacrum are consistent with the displacement of the posterior rotation angle, and the order from largest to smallest is IC, AIIS, ASIS + AIIS, IC + AIIS and S1 screw. The longitudinal displacement of IC is greater than that of the other models. The displacements of ASIS + AIIS and IC + AIIS are similar and the latter is smaller. In the simulated semi-recumbent position, the vertical displacement and posterior rotation angle displacement of the midpoint on the upper surface of the sacrum are also consistent, ranking from large to small: IC, AIIS, ASIS + AIIS, IC + AIIS and S1 screw. Under the simulated left-right compression load state, the lateral displacements of the highest point of the lateral sacral fracture end are consistent with the highest point of the lateral pubic fracture end, and the order from large to small is S1 screw, IC, AIIS, ASIS + AIIS and IC + AIIS, among which the displacements of S1 screw and IC are larger, and the displacements of ASIS + AIIS and IC + AIIS are similar and smaller than those of other models. The displacements of IC + AIIS are smaller than those of ASIS + AIIS. Under the simulated anterior-posterior shear load condition, the posterior displacements of the highest point of the lateral sacral fracture end and the highest point of the lateral pubic fracture end are also consistent, ranking from large to small: IC, AIIS, ASIS + AIIS, IC + AIIS and S1 screw. Among them, the displacements of IC and AIIS are larger. The displacements of ASIS + AIIS and IC + AIIS are similar and the latter are smaller. For the unstable pelvic injury represented by Tile C pelvic fracture, the biomechanical various stabilities of the combination of IC and AIIS are superior to those of the external fixators of conventional configurations. The biomechanical stabilities of the combination of ASIS and AIIS are also better than those of the external fixators of conventional configurations, and slightly worse than those of the combination of IC and AIIS. Compared with sacroiliac screw and conventional external fixators, the lateral stabilities of IC + AIIS and ASIS + AIIS are particularly prominent.

Evaluation of canine adipose-derived mesenchymal stem cells for neurological functional recovery in a rat model of traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) is a common condition in veterinary medicine that is difficult to manage.Veterinary regenerative therapy based on adipose mesenchymal stem cells seem to be an effective strategy for the treatment of traumatic brain injury. In this study, we evaluated therapeutic efficacy of canine Adipose-derived mesenchymal stem cells (AD-MSCs)in a rat TBI model, in terms of improved nerve function and anti-neuroinflammation. RESULTS: Canine AD-MSCs promoted neural functional recovery, reduced neuronal apoptosis, and inhibited the activation of microglia and astrocytes in TBI rats. According to the results in vivo, we further investigated the regulatory mechanism of AD-MSCs on activated microglia by co-culture in vitro. Finally, we found that canine AD-MSCs promoted their polarization to the M2 phenotype, and inhibited their polarization to the M1 phenotype. What's more, AD-MSCs could reduce the migration, proliferation and Inflammatory cytokines of activated microglia, which is able to inhibit inflammation in the central system. CONCLUSIONS: Collectively, the present study demonstrates that transplantation of canine AD-MSCs can promote functional recovery in TBI rats via inhibition of neuronal apoptosis, glial cell activation and central system inflammation, thus providing a theoretical basis for canine AD-MSCs therapy for TBI in veterinary clinic.

Incidence of Adjacent Segment Degeneration and Its Associated Risk Factors Following Anterior Cervical Discectomy and Fusion: A Meta-Analysis.

OBJECTIVE: This study aimed to investigate the incidence of adjacent segment degeneration (ASD) and its associated risk factors in adults after anterior cervical discectomy and fusion (ACDF) surgery. METHODS: An exhaustive search across multiple databases was conducted, including Embase, PubMed, Cochrane Library, and the Web of Science, to identify pertinent studies. We collected such patient data as demographic variables (including age, gender, body mass index), cervical spondylosis type (such as radiculopathy and myelopathy), diabetes status, smoking and drinking history, and radiological risk factors (such as preoperative ASD status, developmental spinal stenosis, T1 slope, and postoperative less cervical lordosis). Incidence estimates were calculated based on relevant data. Risk factors were assessed using odds ratios and weighted mean differences with 95% confidence intervals (CIs). RESULTS: Our analysis incorporated a total of 21 studies for incidence analysis. The overall incidence of CASD following ACDF was found to be 11% and radiographical ASD was 30%. Old age (weighted mean difference = 3.21; 95% CI: 0.06, 6.36; P = 0.05), preoperative ASD status (odds ratio = 2.65; 95% CI: 1.53, 4.60; P < 0.01), developmental spinal stenosis (odds ratio = 2.46; 95% CI: 1.61, 3.77; P < 0.01), and postoperative reduction in cervical lordosis were identified as significant risk factors for the occurrence of CASD. CONCLUSIONS: The incidence of CASD following ACDF was 11%. Risk factors for CASD included old age, preoperative adjacent segment degeneration, developmental spinal stenosis, and postoperative reduction in cervical lordosis. These findings provide valuable insights for the assessment of adjacent segment disease risk after ACDF, aiding surgeons in diagnosis and treatment decisions.

Characterization of Canine Gingival-Derived Mesenchymal Stem Cells and Their Exosomes.

Mesenchymal stem cells (MSCs) can be isolated from numerous tissues and have the potential for self-renewal and multidirectional differentiation. Evidence is accumulating which suggests that MSCs are also present in the gingival tissue. This study aimed to evaluate the feasibility of collecting, purifying, and amplifying gingival-derived MSCs (GMSCs) from canine gingiva and to obtain GMSC-derived exosomes (GMSC-exo). GMSCs were isolated and cultured; furthermore, cellular immunofluorescence demonstrated that GMSCs possess characteristic MSC markers, and in vitro differentiation was induced, indicating that GMSCs can differentiate into multiple lineages. GMSC-exo was successfully extracted from GMSCs supernatant and found that they exhibit the typical characteristics of exosomes as analyzed by transmission electron microscopy, nanoflow analysis, and western blotting. GMSC-exo promoted the proliferation and migration of Madin-Darby canine kidney cells. It was concluded that canine gingiva is a good source of MSCs. Additionally, GMSC-exo is a potentially promising cell-free therapeutic tool for the treatment of canine gingival diseases.

Human umbilical cord mesenchymal stem cell-derived exosomes promote neurological function recovery in rat after traumatic brain injury by inhibiting the activation of microglia and astrocyte.

Traumatic brain injury (TBI) is a serious neurological disorder with increasing worldwide incidence. Emerging evidence has shown a significant therapeutic role of mesenchymal stem cells (MSCs) derived exosomes on traumatic brain injury with broad application prospects as a cell-free therapy. However, a comprehensive understanding of its underlying mechanism remained elusive. In this study, umbilical cord mesenchymal stem cells (UCMSCs)-derived exosomes (UC-MSCs-Exo) were isolated by ultracentrifugation and injected intraventricularly in a rat model of TBI. Our results showed that UC-MSCs-Exo promoted functional recovery and reduced neuronal apoptosis in TBI rats. Moreover, UC-MSCs-Exo inhibited the activation of microglia and astrocytes during brain injury, thereby promoting functional recovery. However, the effect of UC-MSCs-Exo on the content of plasma inflammatory factors in rats was not significant. Collectively our study suggested that UC-MSCs-Exo promotes the recovery of neurological function in TBI rats by inhibiting the activation of microglia and astrocytes, providing a theoretical basis for new therapeutic strategies for central nervous system diseases.

Response of canonical Wnt/ß-catenin signaling pathway in the intestine to microgravity stress in Caenorhabditis elegans.

Considering the short life-cycle property, Caenorhabditis elegans is a suitable animal model to evaluate the long-term effects of microgravity stress on organisms. Canonical Wnt/ß-catenin signaling is evolutionarily conserved in various organisms. We here investigated the response of canonical Wnt/ß-catenin signaling pathway to microgravity stress in nematodes. We observed the noticeable response of canonical Wnt/ß-catenin signaling to microgravity stress. In contrast, we did not detect the obvious response of non-canonical Wnt/ß-catenin signaling to microgravity stress. The canonical ß-catenin BAR-1 acted in the intestine to regulate the response to simulated microgravity. Moreover, in the intestine, we identified a signaling cascade of canonical Wnt/ß-catenin signaling pathway in response to simulated microgravity, and this signaling cascade contained Frizzled receptor MIG-1, Disheveled protein DSH-2, GSK3A/GSK-3, and ß-catenin transcriptional factor BAR-1. Our data suggests an important protective response of canonical Wnt/ß-catenin signaling to simulated microgravity in nematodes.