ObjectiveTo investigate the expression change of cathepsin B (CathB) in the ventroposterior nucleus (VPN) of the ipsilateral thalamus after cortical infarction in rats.MethodsThe adult male Sprague-Dawley rats were randomly divided into either a sham operation group or a model group.The latter was further divided into postoperative 1-, 2-, 3-, 4-, and 8-week groups.A model of cerebral cortical infarction was induced by electrocoagulation the cortical branch of middle cerebral artery.Immunohistochemical staining and immunofluorescence were used to detect the protein expression and cellular localization of CathB in the VPN at each time point.ResultsThe expression level of VPN CathB in thalamus increased gradually after cerebral cortical infarction.It reached the peak at 4 weeks, and decreased at 8 weeks, however it was still higher than the control group (all P<0.05).The release of CathB from the lysosomes into the cytoplasm were found.In addition, the expression level of CathB in the activated astrocytes was significantly increased at 3 weeks after cerebral cortical infarction.ConclusionsDuring 1-8 week after cerebral cortex infarction, CathB in the VPN of the ipsilateral thalamus maintained higher expression level, suggesting that it might play a certain role in secondary degeneration in the thalamus after cerebral cortical infarction.

p75 neurotrophin receptor (p75 NTR) is a member of the tumor necrosis factor receptor superfamily, which interacts with tropomyosin receptor kinase (Trk) receptor or binds neurotrophic factors. It mediates a variety of complex signal transduction pathways, induces synaptic growth and affects cell survival. After acute cerebral ischemia, p75 NTR binds effector factors such as pro-nerve growth factor (proNGF) and sortilin, activating downstream apoptotic signal molecules and leading to neuronal death. Therefore, elucidating the pathways and molecular mechanisms of p75 NTR that mediate neuronal apoptosis in acute cerebral ischemia is of great significance for the development of new therapeutic drugs for acute cerebral ischemia.

The disorder of autophagy lysosomal pathway (ALP) is an important pathogenesis of neuronal damage after cerebral ischemia, and the restoration of ALP may alleviate neuronal damage after cerebral ischemia. As the main transcription factor regulating ALP, transcription factor EB (TFEB) can directly regulate autophagosome generation, autophagosome-lysosome fusion, and autophagic flux by regulating the expression of autophagic genes and lysosomal genes. Therefore, regulating TFEB can alleviate ALP dysfunction and thereby reduce cerebral ischemic damage. This article reviews the structure, biological function of TFEB and its role in regulating ALP to alleviate neuronal damage after cerebral ischemia.

Gap junction proteins have a significant impact on the propagation of neuroinflammation after cerebral ischemia.Connexin 43(Cx43),the principal connexin in the central nervous system,typically assembles hexameric hemichannels in an oligomeric state that dock with hemichannels on adjacent cells to form gap junction channels.Ordinarily,the likelihood of cell surface hemichannels opening is minimal.However,during cerebral ischemia,the excessive activation of Cx43 hemichannels leads to the liberation of a substantial quantity of ions(Na+,Cl-,Ca2+,and K+),glutamate,aspartate,and adenosine triphosphate(ATP),thereby resulting in impairment of adjacent cells and aggravation of neuronal injury.Furthermore,the activation of Cx43 hemichannels triggers the release of inflammatory factors,which exhibits a strong association with the activation of NLRP3 inflammasome after cerebral ischemia.Hence,the modulation of Cx43 hemichannels presents a potential avenue for mitigating neuroinflammation and subsequently diminishing cerebral ischemic injury.This article focuses on the relationship between Cx43 hemichannels and NLRP3 inflammasome activation,as well as its role in cerebral ischemia,all of which provide novel insights and therapeutic approaches for managing cerebral ischemia.

CCAAT/enhancer binding protein β (C/EBPβ), a transcriptional factor of the basic-leucine zipper family, can regulate the transcription activity of downstream target genes. After acute cerebral ischemia, the activity of C/EBPβ changes, and participates in the process of cerebral ischemia injury by regulating neuronal apoptosis and inflammation. This article reviews the molecular biological characteristics of C/EBPβ and its expression changes and role in acute cerebral ischemia, providing a basis for developing new neuroprotective drugs for acute cerebral ischemia using C/EBPβ as therapeutic target.

As the main water channel expressed in the brain,aquaporin 4(AQP4)has been implicated in the pathological process of ischemic stroke.After ischemic stroke,the expression,phosphorylation and polarity distribution of AQP4 are affected by the process of transcription and post-translational modification.The paper summarized the basic structure,physiological function,dynamic expression changes and mechanisms of AQP4 in this review,specifically discussing the role of AQP4 in cerebral edema,blood-brain barrier permeability and neuroinflammation after ischemic stroke,offering an up-to-date perspective on further effective therapeutic strategies for ischemic stroke.

Objective To explore the effects of M1 polarization of microglia on secondary damage in the thalamus after cerebral cortical infarction.Methods A focal cortical infarct model of adult male SD rats was pre-pared using eletrocoagulation and randomized into Sham and model groups at different time points 1～4 weeks after surgery.Based on the assessment of neurofunctional changes in each group of rats,immunohistochemistry was used to observe the number and morphology of NeuN,GFAP and Iba-1 positive cells in(Ventral posterior nucleus of thalamus,VPN)of the ipsilateral thalamus after distal middle cerebral artery occlusion(dMCAO).Immunofures-cence was used to detect the number and morphology of M1 microglia marker(Iba-1+/CD68+cells)and M2 microg-lia marker(Iba-1+/CD206+cells)in VPN of the ipsilateral thalamus after dMCAO.Western blot was used to detect the expression levels of IL-1β,TNF-α,IL-10 and Arg-1 in VPN of the ipsilateral thalamus after dMCAO.Results The results of immunohistochemistry showed a significant decrease in NeuN positive cells and an increase in the density of GFAP and Iba-1 in the ipsilateral VPN of rats after dMCAO when compared with Sham group(P<0.001).Compared with sham group,the protein levels of TNF α and IL-1β were elevated in the ipsilateral VPN elevated(P<0.05).In addition,the model group rats exhibited higher Bederson scores,beam-walking test and adhesive removal test scores after dMCAO compared with Sham group(P<0.05).The numbers of M1 microglia marker(Iba-1+/CD68+cells)were significantly increased when compared with M2 microglia marker(Iba-1+/CD206+cells)in ipsilateral VPN of rats after dMCAO.Conclusion M1 polarization of microglia may play an essential role in secondary damage of thalamus after cerebral cortical infarction.