Neutrophil peptide 1 accelerates the clearance of degenerative axons during Wallerian degeneration by activating macrophages after peripheral nerve crush injury

Macrophages play an important role in peripheral nerve regeneration,but the specific mechanism of regeneration is still unclear.Our preliminary findings indicated that neutrophil peptide 1 is an innate immune peptide closely involved in peripheral nerve regeneration.However,the mechanism by which neutrophil peptide 1 enhances nerve regeneration remains unclear.This study was designed to investigate the relationship between neutrophil peptide 1 and macrophages in vivo and in vitro in peripheral nerve crush injury.The functions of RAW 264.7 cells we re elucidated by Cell Counting Kit-8 assay,flow cytometry,migration assays,phagocytosis assays,immunohistochemistry and enzyme-linked immunosorbent assay.Axonal debris phagocytosis was observed using the CUBIC(Clear,Unobstructed Brain/Body Imaging Cocktails and Computational analysis)optical clearing technique during Wallerian degeneration.Macrophage inflammatory factor expression in different polarization states was detected using a protein chip.The results showed that neutrophil peptide 1 promoted the prolife ration,migration and phagocytosis of macrophages,and CD206 expression on the surfa ce of macrophages,indicating M2 polarization.The axonal debris clearance rate during Wallerian degeneration was enhanced after neutrophil peptide 1 intervention.Neutrophil peptide 1 also downregulated inflammatory factors interleukin-1α,-6,-12,and tumor necrosis factor-αin invo and in vitro.Thus,the results suggest that neutrophil peptide 1 activates macrophages and accelerates Wallerian degeneration,which may be one mechanism by which neutrophil peptide 1 enhances peripheral nerve regeneration.

FK506 contributes to peripheral nerve regeneration by inhibiting neuroinflammatory responses and promoting neuron survival

FK506(Tacrolimus)is a systemic immunosuppressant approved by the U.S.Food and Drug Administration.FK506 has been shown to promote peripheral nerve regeneration,however,its precise mechanism of action and its pathways remain unclear.In this study,we established a rat model of sciatic nerve injury and found that FK506 improved the morphology of the injured sciatic nerve,increased the numbers of motor and sensory neurons,reduced inflammatory responses,markedly improved the conduction function of the injured nerve,and promoted motor function recovery.These findings suggest that FK506 promotes peripheral nerve structure recovery and functional regeneration by reducing the intensity of inflammation after neuronal injury and increasing the number of surviving neurons.

Long-term bone and lung consequences associated with hospital-acquired severe acute respiratory syndrome:a 15-year follow-up from a prospective cohort study

The most severe sequelae after rehabilitation from SARS are femoral head necrosis and pulmonary fibrosis. We performed a 15-year follow-up on the lung and bone conditions of SARS patients. We evaluated the recovery from lung damage and femoral head necrosis in an observational cohort study of SARS patients using pulmonary CT scans, hip joint MRI examinations, pulmonary function tests and hip joint function questionnaires. Eighty medical staff contracted SARS in 2003. Two patients died of SARS, and78 were enrolled in this study from August 2003 to March 2018. Seventy-one patients completed the 15-year follow-up. The percentage of pulmonary lesions on CT scans diminished from 2003(9.40 ± 7.83)% to 2004(3.20 ± 4.78)%(P < 0.001) and remained stable thereafter until 2018(4.60 ± 6.37)%. Between 2006 and 2018, the proportion of patients with interstitial changes who had improved pulmonary function was lower than that of patients without lesions, as demonstrated by the one-second ratio(FEV1/FVC%, t = 2.21, P = 0.04) and mid-flow of maximum expiration(FEF25%–75%, t = 2.76, P = 0.01). The volume of femoral head necrosis decreased significantly from 2003(38.83 ± 21.01)% to 2005(30.38 ± 20.23)%(P = 0.000 2), then declined slowly from 2005 to 2013(28.99 ± 20.59)% and plateaued until 2018(25.52 ± 15.51)%. Pulmonary interstitial damage and functional decline caused by SARS mostly recovered, with a greater extent of recovery within 2 years after rehabilitation. Femoral head necrosis induced by large doses of steroid pulse therapy in SARS patients was not progressive and was partially reversible.

Absorbable implants in sport medicine and arthroscopic surgery:A narrative review of recent development

Over the past two decades,advances in arthroscopic and minimally invasive surgical techniques have led to significant growth in sports medicine surgery.Implants such as suture anchors,interference screws,and endo-buttons are commonly used in these procedures.However,traditional implants made of metal or inert materials are not absorbable,leading to complications that affect treatment outcomes.To address this issue,absorbable materials with excellent mechanical properties,good biocompatibility,and controlled degradation rates have been developed and applied in clinical practice.These materials include absorbable polymers,absorbable bioceramics,and absorbable metals.In this paper,we will provide a comprehensive summary of these absorbable materials from the perspective of clinicians,and discuss their clinical applications and related research in sport medicine.

Perceiving the connection between the bone healing process and biodegradation of biodegradable metal implants through precise bioadaptability principle

The implants made of metallic biomaterials help healing the bone fracture but also affect the bone repair process.As proposed in Matter 4(2021)2548–2650 by Wang et al.,a precisely adaptable biomaterial ought to recapitulate the targeted tissue with spatiotemporal precision and hierarchical accuracy,ranging from atoms and molecules(genes,proteins,etc.)to cells(including organelles)and to tissues and organs.In comparison to traditional bio-inert metallic bone implants such as Co-based alloys and Ti alloys,biodegradable metal(Mg and Zn alloys)bone implants had been developed and might arise many unexpected variables in the bone repair,due to their bioactive nature.In this paper,the bone repair without and with the presence of metallic implants is compared.Thereafter,the perspectives concerning the interactions between the bone tissues and biodegradable metal implants are put forward,and how to better mimic in vivo biodegradation by in vitro experiments is proposed for further research and development of biodegradable metals.

Crystal Structure and Host-Guest Binding Ability of Three Types of Pillar[5]arenes

A systematic research of the structural characterization and the host-guest binding abilities between three types of pillar[5]arenes 3-5(3 for Structure Type I,4 for Structure Type II and 5 for Structure Type III)is carried out by 1H NMR measurements and X-ray study.The results show that the configurations or symmetry of their cavities not only have large difference in these three types of pillar[5]arenes,but also have more or less variations even in the same structure type or the same host locked different guests such as crystals of 3a-3b,4a-4d.On the other hand,the complexation behavior of pillar[5]arenes with 1,4-dibromobutane(DBB)is affected by the different symmetri-cal structure or substituents on the rings.