Quantitatively assessing the effect of cervical sagittal alignment on dynamic intervertebral kinematics by video-fluoroscopy technique.

BACKGROUND: Cervical sagittal alignment is crucial for distributing the head load to lower cervical segments and maintaining normal cervical spine function, but its biomechanical effect on the cervical spine was not fully elucidated. OBJECTIVE: To investigate the effect of cervical sagittal alignment on dynamic intervertebral kinematics. DESIGN: Cross-sectional study. METHODS: Healthy participants without neck pain were recruited and divided into lordosis, straight and kyphosis groups according to the C2-C7 Cobb angle at the neutral position. The anti-directional and total joint motions were extracted across 10 epochs of dynamic cervical flexion and extension movements. RESULTS: /findings: The overall anti-directional joint motion during flexion is larger in the kyphosis group when compared with the lordosis group (p = 0.021), while the range of flexion is smaller in the kyphosis group than that in the lordosis group (p = 0.017). The C2/C3 anti-directional joint motion during extension in the straight group is larger than that in the lordosis group (p = 0016). The range of extension in the kyphosis group (p < 0.001) and the straight group (p = 0.002) are larger than that in the lordosis group. The increased range of extension in the kyphosis and straight groups were mainly from the C3/C4, C4/C5, and C5/C6 joints(p < 0.05). CONCLUSION: Changes in cervical sagittal alignment alter both the quality and quantity of the individual joint motions. More adjustments are required by the cervical joints to complete neck movements with the loss of lordosis. The lordotic curvature is a relatively effort-saving mode for the cervical spine from a biomechanical perspective.

NLRP3-GSDMD-dependent IL-1ß Secretion from Microglia Mediates Learning and Memory Impairment in a Chronic Intermittent Hypoxia-induced Mouse Model.

Hypoxia/reoxygenation caused by chronic intermittent hypoxia (CIH) plays an important role in cognitive deficits in patients with obstructive sleep apnea. However, the precise underlying mechanism remains unclear. This study investigated whether the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is involved in CIH-induced spatial learning and memory impairment in mice, and the possible underlying upstream and downstream mechanisms. The C57BL/6 male mice were exposed to CIH (21% O2-6% O2, 4 min/cycle, 8 h/day) for 9 weeks to investigate the role of NLRP3 in CIH-induced spatial learning and memory impairment in mice. BV2 cells were exposed to intermittent hypoxia (21% O2-1% O2, 90 min/cycle) for 48 h to investigate the possible mechanisms in vitro. We found that: 1) inhibition of NLRP3 inflammasome activation improved CIH-induced spatial learning and memory impairment in mice. 2) CIH damaged hippocampal neurons but increased the number of microglia in mice hippocampi; CIH activated microglia-specific NLRP3 inflammasome, leading to upregulation of matured IL-1ß and N-GSDMD. 3) intermittent hypoxia activated NLRP3 inflammasome via the ROS-NF-κB signaling pathway to promote the release of matured IL-1ß from microglia in a GSDMD-dependent manner without pyroptosis. 4) The IL-1ß released from microglia might impair the synaptic plasticity of hippocampal CA3-CA1 synapses by acting on IL-1 receptors in hippocampal neurons. Our findings reveal that ROS-NF-κB-NLRP3 inflammasome-GSDMD dependent IL-1ß release from microglia may participate in CIH-induced spatial learning and memory impairment by acting on hippocampal neuronal IL-1 receptor, leading to synaptic plasticity impairment.

Urolithin A alleviates neuropathic pain and activates mitophagy.

Neuropathic pain (NP) occurs frequently in the general population and has a negative impact on the quality of life. There is no effective therapy available yet owing to the complex pathophysiology of NP. In our previous study, we found that urolithin A (UA), a naturally occurring microflora-derived metabolite, could relieve NP in mice by inhibiting the activation of microglia and release of inflammation factors. Here in this study, we sought to investigate whether mitophagy would be activated when UA alleviated NP in mice. We showed that the autophagy flow was blocked in the spinal dorsal horn of the chronic constriction injury (CCI) mice when the most obvious pain behavior occurs. Intraperitoneal injection of UA markedly activated the mitophagy mediated by PTEN-induced kinase 1/Parkin, promoted mitobiogenesis in both neurons and microglia, and alleviated NP in the CCI mice. In summary, our data suggest that UA alleviates NP in mice and meanwhile induces mitophagy activation, which highlights a therapeutic potential of UA in the treatment of NP.

[Research on the mechanism of hypoxia promoting the migration of lung adenocarcinoma A549 cells].

Objective: To investigate the mechanism that hypoxia promotes the migration of lung adenocarcinoma A549 cells. Methods: A549 cells were cultured and cells that knockdown of acetyl-CoA carboxylase 1 (ACC1) were obtained by transfection with lentivirus, and cells that knockdown of sterol regulatory element-binding proteins-1 (SREBP-1) were obtained by treated with si-RNA. A549 cells were treated with hypoxia combined with hypoxia inducible factor-1α (HIF-1α) inhibitor PX-478 (25 µmol); Hypoxia combined with linoleic acid (LA) (20 µmol) treated A549 cells with ACC1 knockdown, and A549 cells with SREBP-1 knockdown were treated by hypoxia. Transwell migration assay was used to detect cell migration. Western blot was conducted to detect HIF-1α, ACC1 and epithelial mesenchymal transition (EMT) related proteins, Vimentin, E-Cadherin and SREBP-1; Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was performed to detect the changes of ACC1 and SREBP-1 mRNA in A549 cells after hypoxia and HIF-1α inhibitor PX-478 (25 µmol) treatment. Each experiment was repeated three times. Results: Compared with the normoxic control group, hypoxia promoted the migration of A549 cells (P＜0.01), and up-regulated the expressions of ACC1, HIF-1α (all P＜0.01) and SREBP-1 (P＜0.05). PX-478 (25 µmol) inhibited the migration of A549 cells induced by hypoxia and down-regulated the expression of SREBP-1 (all P＜0.05). ACC1 mRNA and SREBP-1 mRNA levels were increased after hypoxia treatment of A549 cells (all P＜0.05). The levels of ACC1 mRNA and SREBP-1 mRNA were decreased after A549 cells treated with hypoxia combined with PX-478 (25 µmol) for 24 h (P＜0.05, P＜0.01). Knockdown of SREBP-1 in A549 cells was obtained by transfection with si-RNA. Transwell migration assay showed the number of cell migration in si-SREBP-1 group was less than that in normoxia control group (P＜0.01). The si-SREBP-1 group and the si-NC group were treated with hypoxia. Compared with the control group, the number of cell migration in the si-SREBP-1 group was decreased (P＜0.01), however, the difference was not statistically significant compared with the normoxia si-SREBP-1 group (P＞0.05). Western blot showed that the expression of ACC1 in the si-SREBP-1 group was lower than that in the control group (P＜0.01). Compared with the control group, the expression of ACC1 was decreased after si-SREBP-1 group treated with hypoxia (P＜0.01). Knockdown of ACC1 inhibited the migration of A549 cells (P＜0.05). After knockdown of ACC1, the migration number of A549 cells under normoxia and 5% O2 conditions had no significant difference (P＞0.05). Application of LA under hypoxia condition rescued ACC1-knockdown induced inhibitory effect on hypoxia-promoted A549 cell migration (P＜0.05). Conclusion: Hypoxia promotes migration of lung adenocarcinoma A549 cells by regulating fatty acid metabolism through HIF-1α/SREBP-1/ACC1 pathway.

Quantitative initial safety range of early passive rehabilitation after ankle fracture surgery.

BACKGROUND: Early rehabilitation training after ankle fracture surgery is critical to healing and avoiding complications. Inappropriate or excessive motion may impede healing or even lead to secondary injury. Currently, there is a lack of scientific quantitative postoperative rehabilitation methods after ankle fracture. Our purpose was to develop a universal method of quantifying early passive rehabilitation training after surgery by finite element (FE) analysis. METHODS: A three-dimensional (3D) FE model of normal ankle was reconstructed from a computed tomography scan of a healthy male adult. Six types of ankle fractures were considered based on AO classification. We exerted joint motion load to explore the effect of movement on ankle joint mechanics after surgery. The corresponding relationship between the Inter-bone displacement and range of motion was measured to quantifying the ankle range of motion. The 44A3.3 fracture was used as an example to describe the implementation process in detail. RESULTS: During ankle movement, most of the stress was sustained by the internal fixation devices, and the ratio of stress borne by the implants ranged from 67.9 to 94.9%. Flexion/extension exercise did not cause extra stress on the ankle contact surfaces. Ligament traction was the reason for ankle load during flexion/extension motion. The range of early passive postoperative rehabilitation training for six types of ankle fractures (AO classification) were provided. CONCLUSION: A quantitative method of early passive rehabilitation training after ankle fracture surgery was developed using FE analysis. This modeling method has universality for any fracture that can be reconstructed.