Sigma-1 receptor knockout disturbs gut microbiota, remodels serum metabolome, and exacerbates isoprenaline-induced heart failure.

Introduction: Heart failure (HF) is usually the end stage of the continuum of various cardiovascular diseases. However, the mechanism underlying the progression and development of HF remains poorly understood. The sigma-1 receptor (Sigmar1) is a non-opioid transmembrane receptor implicated in many diseases, including HF. However, the role of Sigmar1 in HF has not been fully elucidated. Methods: In this study, we used isoproterenol (ISO) to induce HF in wild-type (WT) and Sigmar1 knockout (Sigmar1-/-) mice. Multi-omic analysis, including microbiomics, metabolomics and transcriptomics, was employed to comprehensively evaluate the role of Sigmar1 in HF. Results: Compared with the WT-ISO group, Sigmar1-/- aggravated ISO-induced HF, including left ventricular systolic dysfunction and ventricular remodeling. Moreover, Sigmar1-/- exacerbated ISO-induced gut microbiota dysbiosis, which was demonstrated by the lower abundance of probiotics g_Akkermansia and g_norank_f_Muribaculaceae, and higher abundance of pathogenic g_norank_f_Oscillospiraceae and Allobaculum. Furthermore, differential metabolites among WT-Control, WT-ISO and Sigmar-/--ISO groups were mainly enriched in bile secretion, tryptophan metabolism and phenylalanine metabolism, which presented a close association with microbial dysbiosis. Corresponding with the exacerbation of the microbiome, the inflammation-related NOD-like receptor signaling pathway, NF-kappa B signaling pathway and TNF signaling pathway were activated in the heart tissues. Conclusion: Taken together, this study provides evidence that a Sigmar1 knockout disturbs the gut microbiota and remodels the serum metabolome, which may exacerbate HF by stimulating heart inflammation.

Research on pharyngeal bacterial flora in transoral atlantoaxial operation and the postoperative follow-up study.

OBJECTIVES: To study the changes of bacterial flora after a series of preoperative oral disinfection and the postoperative recovery of nerve function of patients with craniovertebral junction disorders who were treated with transoral approach operations. METHODS: This research analyzed 20 cases collected from October 2009 to May 2010. All these patients were with CVJ disorders, including 8 males and 12 females, aged 2 to 66 (38.1 on average), and they were all treated with transoral approach operations. The mucosa samples of the posterior pharyngeal wall were sent for bacteria culture. These samples were collected by sterile cotton swabs at four crucial points, including 3 days before operation/before gargling, 3 days after continuous gargling/after anesthesia intubation on the day of operation, after intraoperative cleaning and washing of the mouth, and after intraoperative iodophor immersion. The microflora was stained by means of smear and further counted after an investigation by microscope. The neural function of patients was evaluated by the ASIA classification and the JOA scores. All patients but two with posterior stabilization performed respectively underwent transoral atlantoaxial reduction plate (TARP) fixation consecutively in the same sitting. A regular reexamination of cervical vertebra with lateral and open mouth X-ray, CT and MRI was conducted after operation to evaluate the reduction of atlantoaxial dislocation, internal fixation position, bone graft fusion, inflammatory lesions and tumor recurrence. RESULTS: This bacteriological research showed that the mucosa of the posterior pharyngeal wall of all the patients was in a sterile state after a series of oral preoperative preparations and intraoperative iodophor disinfection, which was considered as type I incision. The bacterial culture results of the mucosa samples of the posterior pharyngeal wall collected at different time points showed significant differences (χ2 = 42.762, P = 0.000). All the patients had improvement in ASIA, and their neural functions were improved to different levels after operation. There was a significant difference in JOA scores before and after operation (t = 8.677, P = 0.000). Postoperative imaging examination showed that the atlantoaxial screw position was good and firm, and the CVJ disorders were treated appropriately. CONCLUSION: It is safe and effective to cut the posterior pharyngeal muscle layer and implant internal fixation by means of transoral approach.

Characterization and cytocompatibility of 3D porous biomimetic scaffold derived from rabbit nucleus pulposus tissue in vitro.

Intervertebral disc (IVD) degeneration is one of the most important causes of lower back pain. Tissue engineering provides a new method for the experimental treatment of degenerative disc diseases. This study aims to develop a natural, acellular, 3D interconnected porous scaffold derived from the extracellular matrix (ECM) of nucleus pulposus. The nucleus pulposus (NP) was decellularized by sequential detergent-nuclease methods, including physical crushing, freeze-drying and cross-linking. These 3D porous scaffolds were fabricated with a high porosity of (81.28 ± 4.10)%, an ideal pore size with appropriate mechanical properties. Rabbit bone marrow mesenchymal stem cells (rBMSCs) were seeded and cultured on the scaffolds. And the mechanical tests showed the compressive elastic modulus of the scaffolds cultured for 4 weeks reached 0.12 MPa, which was better than that of the scaffolds cultured for 2 weeks (0.07 MPa) and that of the control group (0.04 MPa). Scanning electron microscopy (SEM), histological assays, molecular biology assays revealed that the scaffolds could provide an appropriate microstructure and environment for the adhesion, proliferation, migration and secretion of seeded cells in vitro. As assays like histology, immunohistochemistry and the real-time qRT-PCR showed, NP-like tissues were preliminarily formed. In conclusion, the 3D porous scaffold derived from NP ECM is a potential biomaterial for the regeneration of NP tissues. A natural, acellular, 3D interconnected porous scaffold derived from the extracellular matrix (ECM) of nucleus pulposus was developed by sequential detergent-nuclease and freeze-drying method, which can reduce the damage of protein activity to the minimum. It is very similar to the composition and internal environment of the natural nucleus pulposus, because it derived from the natural nucleus pulposus. Scanning electron microscopy (SEM), histological assays, molecular biology assays revealed that the scaffolds could provide an appropriate microstructure and environment for the adhesion, proliferation, migration, and secretion of seeded cells in vitro.

Long-term antibacterial composite via alginate aerogel sustained release of antibiotics and Cu used for bone tissue bacteria infection.

Bone related-bacterial diseases including wound infections and osteomyelitis (OM) remain a serious problem accompanied with amputation in most severe cases. In this work, we report an exceptional effective antibacterial alginate aerogel, which consists of tigecycline (TGC) and octahedral Cu crystal as an organo-inorganic synergy platform for antibacterial and local infection therapy applications. The alginate aerogel could greatly prolong the release of copper ions and maintain effective antibacterial concentration over 18 days. The result of in-vitro experiments demonstrated that the alginate aerogel has an exceptional effective function on antibacterial activity. Cytotoxicity tests indicated that the alginate aerogel has low biological toxicity (average cell viability >75%). These remarkable results suggested that the alginate aerogel exhibits great potential for the treatment of OM, and has a prosperous future of application in bone tissue engineering.

Biomechanical testing of a unique built-in expandable anterior spinal internal fixation system.

BACKGROUND: Expandable screws have greater pullout strength than conventional screws. The purpose of this study was to compare the biomechanical stability provided by a new built-in expandable anterior spinal fixation system with that of 2 commonly used anterior fixation systems, the Z-Plate and the Kaneda, in a porcine partial vertebral corpectomy model. METHODS: Eighteen porcine thoracolumbar spine specimens were randomly divided into 3 groups of 6 each. A vertebral wedge osteotomy was performed by removing the anterior 2/3 of the L1 vertebral body and the T15/L1 disc. Vertebrae were fixed with the Z-Plate, Kaneda, or expandable fixation system. The 3-dimensional spinal range of motion (ROM) of specimens in the intact state (prior to osteotomy), injured state (after osteotomy), and after internal fixation were recorded. The pullout strength and maximum torque of common anterior screws, the expandable anterior fixation screw unexpanded, and the expandable anterior fixation screw expanded was tested. RESULTS: After internal fixation, the expandable device and Z-plate system exhibited higher left bending motion than the Kaneda system (5.50° and 5.37° vs. 5.04, p = 0.001 and 0.008, respectively), and the Z-plate and Kaneda groups had significantly higher left axial and right axial rotation ROM as compared to the expandable device group (left axial rotation: 5.23° and 5.02° vs. 4.53°; right axial rotation: 5.23° and 5.08° vs. 4.49°). The maximum insertion torque of the expandable device was significantly greater than of a common screw (5.10 vs. 3.75 Ns). The maximum pullout force of the expandable device expanded was significantly higher than that of the common screw and the expandable device unexpanded (3,035.48 N vs. 1,827.38 N and 2,333.49 N). CONCLUSIONS: The built-in anterior fixation system provides better axial rotational stability as compared to the other 2 systems, and greater maximum torque and pullout strength than a common fixation screw.

Osteogenic activity of silver-loaded coral hydroxyapatite and its investigation in vivo.

In this study, the scaffolds based on mineralized silver-loaded coral hydroxyapatites (SLCHAs) were developed for bone regeneration in the radius of rabbit with a 15-mm infective segmental defect model for the first time. The SLCHAs were achieved by surface adsorption and ion-exchange reaction between Ca(2+) of coral hydroxyapatite (CHA) and Ag(+) of silver nitrate with different concentration at room temperature. Release experiment in vitro, X-ray diffraction and scanning electron microscopy equipped with energy-dispersive X-ray spectrometer were applied to exhibit that the scaffold showed some features of natural bone both in main component and hierarchical microstructure. The three-dimensional porous scaffold materials imitate the microstructure of cancellous bone. Mouse embryonic pre-osteoblast cells (MC3T3-E1) were used to investigate the cytocompatibility of SLCHAs, CHA and pure coral. Cell activity were studied with alkaline phosphataseenzyme assay after 2, 4, 6 days of incubation. It was no statistically significant differences in cell activity on the scaffolds of Ag(+)(13.6 µg/mL)/CHA, Ag(+)(1.7 µg/mL)/CHA, CHA and pure coral. The results indicated that the lower silver concentration has little effect on cell activity. In the implantation test, the infective segmental defect repaired with SLCHAs was healed up after 10 weeks after surgery, and the implanted composites were almost substituted by new bone tissue, which were very comparable with the scaffold based on mineralized CHA. It could be concluded that the SLCHAs contained with appropriate silver ionic content could act as biocidal agents and maintain the advantages of mineralized CHA or coral, while avoiding potential bacteria-dangers and toxical heavy-metal reaction. All the above results showed that the SLCHAs with anti-infective would be as a promising scaffold material, which whould be widely applied into the clinical for bone regeneration.

[Repair of radius bone defect with the nano-hydroxyapatite/collagen/calcium alginate].

OBJECTIVE: To explore the osteogenic potential of the nano-hydroxyapatite/collagen/calcium alginate composite implanted in animals. METHODS: Eighteen 3-month-old New Zealand white rabbits were adopted to prepare 15 mm segmental defect model at the middle part of radius. Rabbit models were randomly divided into experimental group and blank control group. Nano-hydroxyapatite/collagen/calcium alginate was implanted into the defects of experimental group. Four, 8, and 12 weeks after operation, all specimens were examined by X-ray and histological methods. RESULTS: All the 18 rabbit models entered the final analysis. X-ray showed that osteotylus was seen in the whole defect area in the experimental group 12 weeks after operation, during which osteogenesis was more obvious than in weeks 4 and 8 and the bridge grafting of defect area was obviously visible. In the blank control group, osteotylus was only observed at the two ends of the defects, and no osteogenesis was found in the central part of the defect area. Histological examination showed that new osteoid formation was seen in internal porous zone in the experimental group in weeks 4 and 8; in week 12, more woven bone-like tissues were visible and trabecular-like structure was formed. CONCLUSION: The nano-hydroxyapatite/ collagen/calcium alginate has good osteogenic potential.

[In vitro drug release from a mitomycin C delivery system and its effect against scar tissue adhesion in vivo].

OBJECTIVE: To develop a chitosan (CH)/polyethylene glycols succinate acid (PEG-SA)-mediated mitomycin C (MMC) delivery system and investigate its drug release characteristics in vitro and its effect against scar tissue adhesion in vivo. METHODS: Mitomycin C loading in the composite CH/PEG-SA/MMC films was determined using ultraviolet. The freeze-dried films were dispersed in 1 ml PBS (pH7.4) and mitomycin C release in vitro was determined according to the mitomycin C concentration-UV value standard curve. The influence of the film structure on the drug release was evaluated. The drug delivery system was then implanted in SD rats, and 4 weeks later, immunohistochemical and histological examinations were carried out to assess the therapeutic effect on epidural scar tissue. RESULTS: The linear regression equation of the mitomycin C concentration-UV value standard curve was y=0.593x(3)-2.563x(2)+25.944x-0.236 (R(2)=1.000). The film demonstrated good drug delivery capability, and 20 mg of the samples in PBS showed a peak mitomycin C release after 12 days of 14.9616 microg/ml, which was higher than the ID(50) of mitomycin C (10.4713 microg/l) to the fibroblasts. On days 18 and 32, another two drug release peaks occurred (14.4824 microg/ml and 11.4092 microg/ml, respectively), followed by maintenance of slow release. Till day 60, the accumulative mitomycin release reached 0.1793 microg/ml, and the loaded drug was ultimately completely released. Significant differences were noted in the hydroxyproline content in the scar tissues of different groups (F=12.085, P=0.000), and the CH/PEG-SA/MMC DDS reduced the amount of scar tissue and promoted its orderly alignment to control potential scar hyperplasia that may compress the spinal cord and nerve roots. CONCLUSION: The composite film for drug delivery possesses good flexibility and mechanical properties and allows sustained drug release of mitomycin C to prevent epidural scar tissue adhesion following lumbar laminectomy.

[Ultrasonographic diagnosis of central slip rupture in the finger extensor mechanism of the proximal interphalangeal joint].

OBJECTIVE: To evaluate the accuracy of ultrasonographic diagnosis for central slip rupture of the finger extensor tendon mechanism of the proximal interphalangeal joint. METHODS: Sixty-seven consecutive patients with injuries to the proximal interphalangeal joint underwent ultrasonic examination with a linear 5-10 MHz hockey stick-shaped scanner head. Meanwhile three methods of physical examination were applied to assess the injury, and the results of ultrasonic detection and physical examinations were compared with surgical findings. RESULTS: Thirty-nine patients with central slip rupture of the finger extensor mechanism were confirmed. Ultrasonography achieved good consistence with surgical findings in injury detection. For ultrasound and physical examinations, the sensitivity for injury detection was 100% and 89.74% with specificity of 96.43% and 82.14%, respectively, showing significant difference (P<0.01). CONCLUSION: As an accurate noninvasive method, ultrasonographic diagnosis can identify central slip rupture in the extensor mechanism of the finger over the proximal interphalangeal joint in early stages.

Effect of aminoguanidine on the recovery of rat hindlimb motor function after spinal cord injury.

OBJECTIVE: To study the effects of aminoguanidine (AG), the inhibitor of inducible nitric oxide synthase (NOS), on the recovery of rat hindlimb motor function after spinal cord injury and explore the possible mechanism. METHODS: Thirty rat models of spinal cord compression injury were established according to Nystrom's method. AG therapy was administered for 4 times at 1 h before and 8, 24, 36 h after the injury, and 24 h after the completion of the therapy, spectrophotography was performed to measure the content of NO and activity of NOS in the injured spinal cord, followed by flow cytometry for determining the apoptotic rate 48 h later. The evaluation of the hindlimb motor function recovery was conducted by electrophysiological method and by measuring the behavior scores. RESULTS: AG significantly decreased the NO content (from 2.2714+/-0.4239 micromol/g.pro to 0.8466+/-0.0477 micromol/g.pro, P <0.05) and NOS activity (from 0.3408+/-0.0228 U/mg pro to 0.2702+/-0.0148 U/mg pro, P <0.05) in the injured spinal cord. The apoptotic rats were also reduced (from 7.88% +/-0.79% to 3.10% +/-0.66%, P <0.05). Four weeks after the therapy, the behavior score of the rats improved from 7.1+/-4.5 to 17.3+/-4.7 (P <0.01), and the latency and amplitude of the motor evoked potentials improved from 0 ms to 8.89+/-0.91 ms and from 0 mv to 1.99+/-0.48 mv respectively, showing significant therapeutic effect of AG (P <0.05). CONCLUSION: AG can improve motor functions of injured spinal cord in rats, possibly resulting from decreased apoptotic cells of the neurons in the spinal cord in the early stages of the injury.

[Role of antisense oligodeoxynucleotide of inducible nitric oxide synthase in the apoptosis and p-p38 MAPK signal transduction in rat neurons after spinal cord injury].

OBJECTIVE: To study the role of antisense oligodeoxynucleotides (ASODN) of inducible nitric oxide synthase (iNOS) on the apoptosis and p-p38 mitogen-activated protein kinase (p-p38 MAPK) signal transduction of the neurons after spinal cord injury (SCI). METHODS: Antisense and non-sense oligodeoxynucleotides of iNOS were designed and synthesized, and injected into the subarachnoid space 12 h before the compressive injury was given to the rat spinal cord. Reverse transcription-PCR and flow-cytometry were used to examine the iNOS mRNA expression and the apoptosis of the neurons within the injured spinal cord. The changes of p-p38 MAPK signal transduction pathway were detected by Western blotting. RESULTS: Obvious increase in iNOS expression and up-regulated p-p38 MAPK were detected after SCI, and neuronal apoptosis was observed in the injured spinal cord. ASODN-iNOS treatment resulted in decreased expression levels of iNOS mRNA and p-p38 MAPK, and the neuronal apoptosis was alleviated. CONCLUSION: ASODN-iNOS inhibits iNOS expression and neuronal apoptosis following SCI which may be related to the p-p38 MAPK signal transduction pathway.