Spinal cord injury:molecular mechanisms and therapeutic interventions

Spinal cord injury(SCI)remains a severe condition with an extremely high disability rate.The challenges of SCI repair include its complex pathological mechanisms and the difficulties of neural regeneration in the central nervous system.In the past few decades,researchers have attempted to completely elucidate the pathological mechanism of SCI and identify effective strategies to promote axon regeneration and neural circuit remodeling.

A review on tribology of polymer composite coatings

Self-lubricating polymer composite coatings,with tailorable tribological and mechanical properties,have been widely employed on mechanical parts to reduce friction and wear,which saves energy and improves the overall performance for applications such as aerospace satellite parts,shafts,gears,and bushings.The addition of functional fillers can overcome the limitations of single-polymer coatings and extend the service life of the coatings by providing a combination of low friction,high wear resistance,high load bearing,high temperature resistance,and high adhesion.This paper compares the heat resistance,and the tribological and mechanical properties of common polymer matrices,as well as the categories of functional fillers that improve the coating performance.Applicable scopes,process parameters,advantages,and limitations of the preparation methods of polymer coatings are discussed in detail.The tribological properties of the composite coatings with different matrices and fillers are compared,and the lubrication mechanisms are analyzed.Fillers reduce friction by promoting the formation of transfer films or liquid shear films.Improvement of the mechanical properties of the composite coatings with fillers of different morphologies is described in terms of strengthening and toughening mechanisms,including a stress transfer mechanism,shear yielding,crack bridging,and interfacial debonding.The test and enhancement methods for the adhesion properties between the coating and substrate are discussed.The coating adhesion can be enhanced through mechanical treatment,chemical treatment,and energy treatment of the substrate.Finally,we propose the design strategies for high-performance polymer composite coating systems adapted to specific operating conditions,and the limitations of current polymer composite coating research are identified.

Temporal and spatial cellular and molecular pathological alterations with single-cell resolution in the adult spinal cord after injury

Spinal cord injury(SCI)involves diverse injury responses in different cell types in a temporally and spatially specific manner.Here,using single-cell transcriptomic analyses combined with classic anatomical,behavioral,electrophysiological analyses,we report,with single-cell resolution,temporal molecular and cellular changes in crush-injured adult mouse spinal cord.Data revealed pathological changes of 12 different major cell types,three of which infiltrated into the spinal cord at distinct times post-injury.We discovered novel microglia and astrocyte subtypes in the uninjured spinal cord,and their dynamic conversions into additional stage-specific subtypes/states.Most dynamic changes occur at 3-days post-injury and by day-14 the second wave of microglial activation emerged,accompanied with changes in various cell types including neurons,indicative of the second round of attacks.By day-38,major cell types are still substantially deviated from uninjured states,demonstrating prolonged alterations.This study provides a comprehensive mapping of cellular/molecular pathological changes along the temporal axis after SCI,which may facilitate the development of novel therapeutic strategies,including those targeting microglia.