Semaphorin3C identified as mediator of neuroinflammation and microglia polarization after spinal cord injury.

Excessive neuroinflammation after spinal cord injury (SCI) is a major hurdle during nerve repair. Although proinflammatory macrophage/microglia-mediated neuroinflammation plays important roles, the underlying mechanism that triggers neuroinflammation and aggravating factors remain unclear. The present study identified a proinflammatory role of semaphorin3C (SEMA3C) in immunoregulation after SCI. SEMA3C expression level peaked 7 days post-injury (dpi) and decreased by 14 dpi. In vivo and in vitro studies revealed that macrophages/microglia expressed SEMA3C in the local microenvironment, which induced neuroinflammation and conversion of proinflammatory macrophage/microglia. Mechanistic experiments revealed that RAGE/NF-κB was downstream target of SEMA3C. Inhibiting SEMA3C-mediated RAGE signaling considerably suppressed proinflammatory cytokine production, reversed polarization of macrophages/microglia shortly after SCI. In addition, inhibition of SEMA3C-mediated RAGE signaling suggested that the SEMA3C/RAGE axis is a feasible target to preserve axons from neuroinflammation. Taken together, our study provides the first experimental evidence of an immunoregulatory role for SEMA3C in SCI via an autocrine mechanism.

Anterior transposition and positioning via helix sling method in cubital tunnel syndrome: An open-label, retrospective trial of maximum 5-year follow-up.

Background: Ulnar nerve transposition is used for cubital tunnel syndrome (CuTS) with nerve instability. The aim is to report a modified technique for ulnar nerve transposition using medial intermuscular septum and Osborne's ligament as a double-strand helix sling to recreate a sliding channel for the ulnar nerve and the functional outcomes at follow-ups. Methods: Twenty-five patients with persistent CuTS underwent nerve release and subcutaneous transposition from January 2017 to January 2022 in our institute. Among them, 9 patients were excluded due to incomplete medical records, lack of follow-up history, or bilateral limb numbness. The medial intermuscular septum with one end attached was excised to rebuild a tension-free double-strand helix sling by anchoring at the residue of Osborne's ligament. The modified Mc-Gowan classification was applied to evaluate the disease severity preoperatively. The quick disability of arm and shoulder and hand (quickDASH) questionnaire and visual analogue scale (VAS) scores were used to evaluate pre- and postoperative symptoms. Ultrasound imaging was utilized for nerve structure evaluation before surgery and at follow-ups. Results: Sixteen out of twenty-five patients received follow-ups postoperatively (ranging from 9 to 69 months, 36 months in average). No findings indicated subluxation of ulnar nerve or recompression by ultrasound imaging examination. According to quickDASH and VAS scores and physical examination, 14 out of 16 patients showed postoperative improvement in symptoms and function at final follow-ups. Interpretation: In this modified technique, the medial intermuscular septum and Osborne's ligament can create tension-free helix sling for stable and smooth sliding and preventing subluxation after nerve transposition, which is highly effective and safe for CuTS treatment.

AAV-mediated VEGFA overexpression promotes angiogenesis and recovery of locomotor function following spinal cord injury via PI3K/Akt signaling.

Spinal cord injury (SCI) is a disorder of the central nervous system resulting from various factors such as trauma, inflammation, tumors, and other etiologies. This condition leads to impairment in motor, sensory, and autonomic functions below the level of injury. Limitations of current therapeutic approaches prompt an investigation into therapeutic angiogenesis through persistent local expression of proangiogenic factors. Here, we investigated whether overexpression of adeno-associated virus (AAV)-mediated vascular endothelial growth factor A (VEGFA) in mouse SCI promoted locomotor function recovery, and whether the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway was mechanistically involved. Three weeks before SCI, AAV-VEGFA was injected at the T10 level to induce VEGFA overexpression. Neurofunctional, histological, and biochemical assessments were done to determine tissue damage and/or recovery of neuromuscular and behavioral impairments. Daily injections of the PI3K/Akt pathway inhibitor LY294002 were made to assess a possible mechanism. AAV-VEGFA overexpression dramatically improved locomotor function and ameliorated pathological injury caused by SCI. Improved motor-evoked potentials in hindlimbs and more spinal CD31-positive microvessels were observed in AAV-VEGFA-overexpressing mice. LY294002 reduced PI3K and Akt phosphorylation levels and attenuated AAV-VEGFA-related improvements. In conclusion, sustained local AAV-mediated VEGFA overexpression in spinal cord can significantly promote angiogenesis and ameliorate locomotor impairment after SCI in a contusion mouse model through activation of the PI3K/Akt signaling pathway.

Modelling osteoarthritis in mice via surgical destabilization of the medial meniscus with or without a stereomicroscope.

AIMS: To evaluate inducing osteoarthritis (OA) by surgical destabilization of the medial meniscus (DMM) in mice with and without a stereomicroscope. METHODS: Based on sample size calculation, 70 male C57BL/6 mice were randomly assigned to three surgery groups: DMM aided by a stereomicroscope; DMM by naked eye; or sham surgery. The group information was blinded to researchers. Mice underwent static weightbearing, von Frey test, and gait analysis at two-week intervals from eight to 16 weeks after surgery. Histological grade of OA was determined with the Osteoarthritis Research Society International (OARSI) scoring system. RESULTS: Surgical DMM with or without stereomicroscope led to decrease in the mean of weightbearing percentages (-20.64% vs -21.44%, p = 0.792) and paw withdrawal response thresholds (-21.35% vs -24.65%, p = 0.327) of the hind limbs. However, the coefficient of variation (CV) of weight-bearing percentages and paw withdrawal response thresholds in naked-eye group were significantly greater than that in the microscope group (19.82% vs 6.94%, p < 0.001; 21.85% vs 9.86%, p < 0.001). The gait analysis showed a similar pattern. Cartilage degeneration was observed in both DMM-surgery groups, evidenced by increased OARSI scores (summed score: 11.23 vs 11.43, p = 0.842), but the microscope group showed less variation in OARSI score than the naked-eye group (CV: 21.03% vs 32.44%; p = 0.032). CONCLUSION: Although surgical DMM aided by stereomicroscope is technically difficult, it produces a relatively more homogeneous OA model in terms of the discrete degree of pain behaviours and histopathological grading when compared with surgical DMM without stereomicroscope.Cite this article: Bone Joint Res 2022;11(8):518-527.

A Novel Delivery Method of Cyclovirobuxine D for Brain-Targeting: Chitosan Coated Nanoparticles Loading Cyclovirobuxine D by Intranasal Administration.

The blood-brain barrier (BBB) restricts the delivery of most drugs to the brain. In our previous study, the feasibility of cyclovirobuxine D delivery to the brain by a non-invasive nasal route was evaluated. In this study, a suitable drug delivery system by way of intranasal administration was developed, which could improve brain targeting. First, a formulation of cyclovirobuxine D (CVB-D) based on chitosan nanoparticles (CS-CVB-D-NPs) was prepared by the modified ionotropic gelation method through single-factor screening experiment. The CS-CVB-D-NPs with a entrapment efficiency (EE) of (62.82±2.59)% were found to be of a narrow polydispersity index (PI) (0.19±0.01) and (235.37± 12.71) nm in size, with a zeta potential of (33.9 ± 1.7) mV. The NPs possessed a sustained release characterization with in vitro release of 88.03 ± 2.30% at 24 h. In vivo, the higher AUC0-t(brain) of CS-CVB-D-NPs by intranasal administration revealed the development of a novel brain-targeting delivery method of CVB-D.

Pharmacokinetic and nephroprotective benefits of using Schisandra chinensis extracts in a cyclosporine A-based immune-suppressive regime.

Cyclosporine A (CsA) is a powerful immunosuppressive drug. However, nephrotoxicity resulting from its long-term usage has hampered its prolonged therapeutic usage. Schisandra chinensis extracts (SCE) have previously been used in traditional Chinese medicine and more recently coadministered with Western medicine for the treatment of CsA-induced side effects in the People's Republic of China. This study aimed to investigate the possible effects of SCE on the pharmacokinetics of CsA in rats and elucidate the potential mechanisms by which it hinders the development of CsA-induced nephrotoxicity. A liquid chromatography/tandem mass spectrometry method was developed and validated for determining the effect of SCE on the pharmacokinetics of CsA. Male Sprague Dawley rats, which were administered with CsA (25 mg/kg/d) alone or in combination with SCE (54 mg/kg/d and 108 mg/kg/d) for 28 days, were used to evaluate the nephroprotective effects of SCE. Our study showed that SCE increased the mean blood concentration of CsA. Furthermore, we found that the concomitant administration of SCE alongside CsA prevented the disruption of catalase activity and reduction in creatinine, urea, renal malondialdehyde, and glutathione peroxidase levels that would have otherwise occurred in the absence of SCE administration. SCE treatment markedly suppressed the expression of 4-hydroxynonenal, Bcl-2-associated X protein, cleaved caspase 3, and autophagy-related protein LC3 A/B. On the other hand, the expression of heme oxygenase-1, nuclear factor erythroid 2-related factor 2 (Nrf2), and P-glycoprotein was enhanced by the very same addition of SCE. SCE was also able to increase the systemic exposure of CsA in rats. The renoprotective effects of SCE were thought to be mediated by its antiapoptotic and antioxidant abilities, which caused the attenuation of CsA-induced autophagic cell death. All in all, these findings suggest the prospective use of SCE as an effective adjunct in a CsA-based immunosuppressive regimen.

An LC/MS quantitative and microdialysis method for cyclovirobuxine D pharmacokinetics in rat plasma and brain: The pharmacokinetic comparison of three different drug delivery routes.

To explore the brain-targeting of cyclovirobuxine D(CVB-D) after administered intranasally, the pharmacokinetics of CVB-D via three different drug delivery routes: intragastric (i.g.), intranasal (i.n.), and intravenous (i.v.) in rat brain and blood was compared. Firstly, an in vivo microdialysis method for sampling CVB-D in both plasma and brain of the rat was established. Secondly, a liquid chromatography-tandem mass spectrometry method has been developed and validated for determination of CVB-D in microdialysis samples. For plasma and brain microdialysis samples, liquid-liquid extraction was used and donepezil was chosen as internal standard. Both were followed by HPLC separation and positive electrospray ionization tandem mass spectrometry detection (ESI-MS/MS). Chromatographic separation was achieved on a agilent C18 column with a mobile phase of methanol-water (50:50, v/v) (pH 3.2) containing 0.1% formic acid and 5mM ammonium acetate. Mass spectrometric detection in the positive ion mode was carried out by selected reaction monitoring (MRM) of the transitions at m/z 403.4→372.3 for CVB-D and m/z 380.2→243.1 for donepezil (IS). Good linearities were obtained in the range of 10-4000ng/mL in rat microdialysates for CVB-D. The lowest limit of quantitation was 5ng/mL, with an extraction recovery >75%, and no significant matrix effects. Intra- and inter-day precisions were all <15% with accuracies of 97.26-116.20%. All of which proved that the established method was successfully applied to the pharmacokinetic study of CVB-D. Simultaneously, brain uptake and pharmacokinetic studies were performed by determination of CVB-D concentration in blood and brain respectively for CVB-D i.g., i.n. and i.v.. Results showed that the intranasal CVB-D could improve brain targeting and had advantages for direct nose to brain transport of CVB-D when compared with injection and oral delivery routes, which indicates that intranasal administration of CVB-D could be a promising approach for the treatment of cerebrovascular disease.