Photobiomodulation inhibits the expression of chondroitin sulfate proteoglycans after spinal cord injury via the Sox9 pathway

Both glial cells and glia scar greatly affect the development of spinal cord injury and have become hot spots in research on spinal cord injury treatment.The cellular deposition of dense extracellular matrix proteins such as chondroitin sulfate proteoglycans inside and around the glial scar is known to affect axonal growth and be a major obstacle to autogenous repair.These proteins are thus candidate targets for spinal cord injury therapy.Our previous studies demonstrated that 810 nm photo biomodulation inhibited the formation of chondroitin sulfate proteoglycans after spinal cord injury and greatly improved motor function in model animals.However,the specific mechanism and potential targets involved remain to be clarified.In this study,to investigate the therapeutic effect of photo biomodulation,we established a mouse model of spinal cord injury by T9 clamping and irradiated the injury site at a power density of 50 mW/cm~2 for 50 minutes once a day for 7 consecutive days.We found that photobiomodulation greatly restored motor function in mice and down regulated chondroitin sulfate proteoglycan expression in the injured spinal cord.Bioinformatics analysis revealed that photobiomodulation inhibited the expression of proteoglycan-related genes induced by spinal cord injury,and versican,a type of proteoglycan,was one of the most markedly changed molecules.Immunofluorescence staining showed that after spinal cord injury,versican was present in astrocytes in spinal cord tissue.The expression of versican in primary astrocytes cultured in vitro increased after inflammation induction,whereas photobiomodulation inhibited the expression of ve rsican.Furthermore,we found that the increased levels of p-Smad3,p-P38 and p-Erk in inflammatory astrocytes were reduced after photobiomodulation treatment and after delivery of inhibitors including FR 180204,(E)-SIS3,and SB 202190.This suggests that Sma d 3/Sox9 and MAP K/Sox9 pathways may be involved in the effects of photobiomodulation.In summary,our findings show that photobiomodulation modulates the expression of chondroitin sulfate proteoglycans,and versican is one of the key target molecules of photo biomodulation.MAPK/Sox9 and Smad3/Sox9 pathways may play a role in the effects of photo biomodulation on chondroitin sulfate proteoglycan accumulation after spinal cord injury.

Upregulation of β-catenin signaling represents a single common pathway leading to the various phenotypes of spinal degeneration and pain

Spine degeneration is an aging-related disease,but its molecular mechanisms remain unknown,although elevatedβ-catenin signaling has been reported to be involved in intervertebral disc degeneration.Here,we determined the role ofβ-catenin signaling in spinal degeneration and in the homeostasis of the functional spinal unit(FSU),which includes the intervertebral disc,vertebra and facet joint and is the smallest physiological motion unit of the spine.We showed that pain sensitivity in patients with spinal degeneration is highly correlated withβ-catenin protein levels.We then generated a mouse model of spinal degeneration by transgenic expression of constitutively activeβ-catenin in Col2^(+) cells.We found thatβ-catenin-TCF7 activated the transcription of CCL2,a known critical factor in osteoarthritic pain.Using a lumbar spine instability model,we showed that aβ-catenin inhibitor relieved low back pain.Our study indicates thatβ-catenin plays a critical role in maintaining spine tissue homeostasis,its abnormal upregulation leads to severe spinal degeneration,and its targeting could be an avenue to treat this condition.

Restoring the dampened expression of the core clock molecule BMAL1 protects against compression-induced intervertebral disc degeneration

The circadian clock participates in maintaining homeostasis in peripheral tissues,including intervertebral discs(IVDs).Abnormal mechanical loading is a known risk factor for intervertebral disc degeneration(IDD).Based on the rhythmic daily loading pattern of rest and activity,we hypothesized that abnormal mechanical loading could dampen the IVD clock,contributing to IDD.Here,we investigated the effects of abnormal loading on the IVD clock and aimed to inhibit compression-induced IDD by targeting the core clock molecule brain and muscle Arnt-like protein-1(BMAL1).In this study,we showed that BMAL1 KO mice exhibit radiographic features similar to those of human IDD and that BMAL1 expression was negatively correlated with IDD severity by systematic analysis based on 149 human IVD samples.The intrinsic circadian clock in the IVD was dampened by excessive loading,and BMAL1 overexpression by lentivirus attenuated compression-induced IDD.Inhibition of the RhoA/ROCK pathway by Y-27632 or melatonin attenuated the compression-induced decrease in BMAL1 expression.Finally,the two drugs partially restored BMAL1 expression and alleviated IDD in a diurnal compression model.Our results first show that excessive loading dampens the circadian clock of nucleus pulposus tissues via the RhoA/ROCK pathway,the inhibition of which potentially protects against compression-induced IDD by preserving BMAL1 expression.These findings underline the importance of the circadian clock for IVD homeostasis and provide a potentially effective therapeutic strategy for IDD.

Interpreting the biochemical specificity of mouse spinal cord by confocal raman microspectral imaging

Interpreting the biochemical specifcity of spinal cord tissue is the essential requirement for underst.anding the biochemical mechanisms during spinal-cord-related pathological course.In this work,a longitudinal study was implemented to reveal a precise linkage betwoen the spectral features and the molecular composition in er vivo mouse spinal cord tissue by microspectral Raman imaging.It was testified that lipid-rich white matter could be distinguished from gray matter not only by the lipid Raman peaks at 1064,1300,1445 and 1660 cm^(-1),but also by protein(1250 and 1328 cm^(-1))and saccharides(913 and 1137 cm^(-1))distributions.K-means cluster analysis was further applied to visualize the morphological basis of spinal cord tissue by chemical components and their dist ribution patterns.T wo-dimensional chemical images were then generated to visualize the contrast between two different tissue types by integrating the intensitics of the featured Raman bands.All the obtained results ilustrated the biochemical characteristics of spinal cord tssue,as well as some specific substance variances bet ween different tssue types,which formed a solid basis for the molecular investigation of spinal cord pathologi cal alterations.

H_(2)预处理增强CuO_(x)/CeO_(2)协同等离子体催化氧化CO的作用机制

一氧化碳(CO)对公众健康和环境都会造成严重危害,低温工况下CO的催化氧化是目前的研究热点之一.低温等离子体(non-thermal plasma,NTP)催化技术在该领域具备独特优势.本研究采用等体积浸渍法制备了CuO_(x)/CeO_(2)催化剂,并对催化剂进行了H_(2)预处理,比较研究了不同湿度条件下NTP催化体系中各类铜铈催化剂催化氧化CO的性能,并探讨了氢气预处理对催化剂的影响及作用机制.结果表明,H_(2)预处理可以增加CuO_(x)/CeO_(2)催化剂NTP氧化CO的活性,同时抑制副产物O_(3)和NO_(x)的排放;其作用机制与催化剂表面Cu^(+)活性位点与氧空位的增加有关.本研究揭示了氢气预处理对NTP协同CuO_(x)/CeO_(2)催化氧化CO的影响,对开发低温等离子体催化系统下多功能催化剂具有一定的参考价值.