Expression of yeast silencing information regulator 2 in secondary injury of intracerebral hemorrhage

Objective:to investigate the expression of yeast silencing information regulator 2(Sirt2)in the secondary injury of intracerebral hemorrhage(ICH).Methods:twelve Sprague Dawley(SD)rats were randomly divided into a sham group and an ICH group,with six rats in each group.A rat model of ICH was established by injecting collagenase type IV into the right striatum of the rats.The expression of Sirt2 was measured by Western blot and immunohistochemistry after ICH.Result:the behavioral score of the ICH rats was the lowest at 48 h after the operation;therefore the rats at 48 h after surgery were selected as the model rats.The expression of Sirt2 was significantly higher in the striatal tissue of the ICH rats compared with the sham group(P<0.05).Conclusion:the expression of Sirt2 around hematoma in ICH rats decreases,and Sirt2 is expected to become a new target for ICH treatment.

Inhibition of endoplasmic reticulum stress alleviates secondary injury after traumatic brain injury

Apoptosis after traumatic brain injury has been shown to be a major factor influencing prognosis and outcome. Endoplasmic reticulum stress may be involved in mitochondrial mediated neuronal apoptosis. Therefore, endoplasmic reticulum stress has become an important mechanism of secondary injury after traumatic brain injury. In this study, a rat model of traumatic brain injury was established by lateral fluid percussion injury. Fluorescence assays were used to measure reactive oxygen species content in the cerebral cortex. Western blot assays were used to determine expression of endoplasmic reticulum stress-related proteins. Hematoxylin-eosin staining was used to detect pathological changes in the cerebral cortex. Transmission electron microscopy was used to measure ultrastructural changes in the endoplasmic reticulum and mitochondria. Our results showed activation of the endoplasmic reticulum stress-related unfolded protein response. Meanwhile, both the endoplasmic reticulum stress response and mitochondrial apoptotic pathway were activated at different stages post-traumatic brain injury. Furthermore, pretreatment with the endoplasmic reticulum stress inhibitor, salubrinal（1 mg/kg）, by intraperitoneal injection 30 minutes before injury significantly inhibited the endoplasmic reticulum stress response and reduced apoptosis. Moreover, salubrinal promoted recovery of mitochondrial function and inhibited activation of the mitochondrial apoptotic pathway post-traumatic brain injury. These results suggest that endoplasmic reticulum stress might be a key factor for secondary brain injury post-traumatic brain injury.

A comprehensive look at the psychoneuroimmunoendocrinology of spinal cord injury and its progression: mechanisms and clinical opportunities

Spinal cord injury(SCI)is a devastating and disabling medical condition generally caused by a traumatic event(primary injury).This initial trauma is accompanied by a set of biological mechanisms directed to ameliorate neural damage but also exacerbate initial damage(secondary injury).The alterations that occur in the spinal cord have not only local but also systemic consequences and virtually all organs and tissues of the body incur important changes after SCI,explaining the progression and detrimental consequences related to this condition.Psychoneuroimmunoendocrinology(PNIE)is a growing area of research aiming to integrate and explore the interactions among the different systems that compose the human organism,considering the mind and the body as a whole.The initial traumatic event and the consequent neurological disruption trigger immune,endocrine,and multisystem dysfunction,which in turn affect the patient's psyche and well-being.In the present review,we will explore the most important local and systemic consequences of SCI from a PNIE perspective,defining the changes occurring in each system and how all these mechanisms are interconnected.Finally,potential clinical approaches derived from this knowledge will also be collectively presented with the aim to develop integrative therapies to maximize the clinical management of these patients.

Tandem Mass Tag-based proteomics analysis reveals the vital role of inflammation in traumatic brain injury in a mouse model

Proteomics is a powerful tool that can be used to elucidate the underlying mechanisms of diseases and identify new biomarkers.Therefore,it may also be helpful for understanding the detailed pathological mechanism of traumatic brain injury(TBI).In this study,we performed Tandem Mass Tag-based quantitative analysis of cortical proteome profiles in a mouse model of TBI.Our results showed that there were 302 differentially expressed proteins in TBI mice compared with normal mice 7 days after injury.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that these differentially expressed proteins were predominantly involved in inflammatory responses,including complement and coagulation cascades,as well as chemokine signaling pathways.Subsequent transcription factor analysis revealed that the inflammation-related transcription factors NF-κB1,RelA,IRF1,STAT1,and Spi1 play pivotal roles in the secondary injury that occurs after TBI,which further corroborates the functional enrichment for inflammatory factors.Our results suggest that inflammation-related proteins and inflammatory responses are promising targets for the treatment of TBI.

Photobiomodulation provides neuroprotection through regulating mitochondrial fission imbalance in the subacute phase of spinal cord injury

Increasing evidence indicates that mitochonarial lission imbalance plays an important role in derayed neuronal cell death. Our previous study round that photo biomodulation improved the motor function of rats with spinal cord injury.However,the precise mechanism remains unclear.To investigate the effect of photo biomodulation on mitochondrial fission imbalance after spinal cord injury,in this study,we treated rat models of spinal co rd injury with 60-minute photo biomodulation(810 nm,150 mW) every day for 14 consecutive days.Transmission electron microscopy results confirmed the swollen and fragmented alte rations of mitochondrial morphology in neurons in acute(1 day) and subacute(7 and 14 days) phases.Photo biomodulation alleviated mitochondrial fission imbalance in spinal cord tissue in the subacute phase,reduced neuronal cell death,and improved rat posterior limb motor function in a time-dependent manner.These findings suggest that photobiomodulation targets neuronal mitochondria,alleviates mitochondrial fission imbalance-induced neuronal apoptosis,and thereby promotes the motor function recovery of rats with spinal cord injury.

Alterations in gut microbiota are related to metabolite profiles in spinal cord injury

Studies have shown that gut microbiota metabolites can enter the central nervous system via the blood-spinal cord barrier and cause neuroinflammation, thus constituting secondary injury after spinal cord injury. To investigate the correlation between gut microbiota and metabolites and the possible mechanism underlying the effects of gut microbiota on secondary injury after spinal cord injury, in this study, we established mouse models of T8–T10 traumatic spinal cord injury. We used 16 S rRNA gene amplicon sequencing and metabolomics to reveal the changes in gut microbiota and metabolites in fecal samples from the mouse model. Results showed a severe gut microbiota disturbance after spinal cord injury, which included marked increases in pro-inflammatory bacteria, such as Shigella, Bacteroides, Rikenella, Staphylococcus, and Mucispirillum and decreases in anti-inflammatory bacteria, such as Lactobacillus, Allobaculum, and Sutterella. Meanwhile, we identified 27 metabolites that decreased and 320 metabolites that increased in the injured spinal cord. Combined with pathway enrichment analysis, five markedly differential amino acids(L-leucine, L-methionine, L-phenylalanine, L-isoleucine and L-valine) were screened out, which play a pivotal role in activating oxidative stress and inflammatory responses following spinal cord injury. Integrated correlation analysis indicated that the alteration of gut microbiota was related to the differences in amino acids, which suggests that disturbances in gut microbiota might participate in the secondary injury through the accumulation of partial metabolites that activate oxidative stress and inflammatory responses. Findings from this study provide a new theoretical basis for improving the secondary injury after spinal cord injury through fecal microbial transplantation.

Quantitative proteomic and phosphoproteomic analyses of the hippocampus reveal the involvement of NMDAR1 signaling in repetitive mild traumatic brain injury

The cumulative damage caused by repetitive mild traumatic brain injury can cause long-term neurodegeneration leading to cognitive impairment.This cognitive impairment is thought to result specifically from damage to the hippocampus.In this study,we detected cognitive impairment in mice 6 weeks after repetitive mild traumatic brain injury using the novel object recognition test and the Morris water maze test.Immunofluorescence staining showed that p-tau expression was increased in the hippocampus after repetitive mild traumatic brain injury.Golgi staining showed a significant decrease in the total density of neuronal dendritic spines in the hippocampus,as well as in the density of mature dendritic spines.To investigate the specific molecular mechanisms underlying cognitive impairment due to hippocampal damage,we performed proteomic and phosphoproteomic analyses of the hippocampus with and without repetitive mild traumatic brain injury.The differentially expressed proteins were mainly enriched in inflammation,immunity,and coagulation,suggesting that non-neuronal cells are involved in the pathological changes that occur in the hippocampus in the chronic stage after repetitive mild traumatic brain injury.In contrast,differentially expressed phosphorylated proteins were mainly enriched in pathways related to neuronal function and structure,which is more consistent with neurodegeneration.We identified N-methyl-D-aspartate receptor 1 as a hub molecule involved in the response to repetitive mild traumatic brain injury,and western blotting showed that,while N-methyl-D-aspartate receptor 1 expression was not altered in the hippocampus after repetitive mild traumatic brain injury,its phosphorylation level was significantly increased,which is consistent with the omics results.Administration of GRP78608,an N-methyl-D-aspartate receptor 1 antagonist,to the hippocampus markedly improved repetitive mild traumatic brain injury-induced cognitive impairment.In conclusion,our findings suggest that N-methyl-D-aspartate receptor 1 signaling in the hippocampus is involved in cognitive impairment in the chronic stage after repetitive mild traumatic brain injury and may be a potential target for intervention and treatment.

Acute respiratory distress syndrome:focusing on secondary injury

Acute respiratory distress syndrome(ARDS)is one of the most common severe diseases seen in the clinical setting.With the continuous exploration of ARDS in recent decades,the understanding of ARDS has improved.ARDS is not a simple lung disease but a clinical syndrome with various etiologies and pathophysiological changes.However,in the intensive care unit,ARDS often occurs a few days after primary lung injury or after a few days of treatment for other severe extrapulmonary diseases.Under such conditions,ARDS often progresses rapidly to severe ARDS and is difficult to treat.The occurrence and development of ARDS in these circumstances are thus not related to primary lung injury;the real cause of ARDS may be the“second hit”caused by inappropriate treatment.In view of the limited effective treatments for ARDS,the strategic focus has shifted to identifying potential or high-risk ARDS patients during the early stages of the disease and implementing treatment strategies aimed at reducing ARDS and related organ failure.Future research should focus on the prevention of ARDS.

Changes in circulating inflammatory cells and the relationship to secondary brain injury in patients with craniocerebral injury

BACKGROUND：Recent studies have indicated that reactive encephalitis plays an important role in secondary tissue damage after craniocerebral injury. OBJECTIVE： To observe changes in white blood cells （WBC） and polymorphonuclear neutrophils （PMN） in peripheral blood, and to determine their role in secondary brain insult in patients with craniocerebral injury. DESIGN, TIME AND SETTING： A case-control study at the Department of Neurosurgery of the Affiliated Hospital North Sichuan University of Medical Sciences between August 2007 and May 2008. PARTICIPANTS： Sixty-three patients, admitted within 24 hours after craniocerebral injury and who received no surgery, were included in the study. The cohort consisted of 41 males and 22 females, aged 9–72 years, with an average age of 42 years. Ten healthy volunteers, selected from the Department of Neurosurgery, were designated as the control group. METHODS： WBC and PMN from the peripheral blood were measured 0, 24, 48, 72, and 168 hours after admission to hospital. The Glasgow coma scale, area of cerebral hemorrhage, and degree of brain edema were simultaneously determined. The Glasgow outcome scale was evaluated six months after injury. The relationship between changes in WBC and PMN were analyzed. Sixty-three patients were divided into 0, 24, 48, 72, and 168 hours groups, with admission time to hospital as the determining factor. As controls, WBC and PMN of peripheral blood were also detected in 10 healthy volunteers. MAIN OUTCOME MEASURES： The main outcome measures were WBC and PMN counts in the peripheral blood at 0, 24, 48, 72, and 168 hours after admission to hospital, the mutual relationship between GCS, WBC and PMN, and changes in brain hemorrhage volume and edema size. RESULTS： WBC peaked at 24 hours after injury, and PMN peaked at 48 hours after injury （P 〈 0.01）. These measures negatively correlated to the Glasgow coma scale （r = -0.657, -0.541, respectively, P 〈 0.05）. In patients with Glasgow coma sale 〈 8, WBC and PMN were significantly higher than in the patients with GCS ≥ 8 （P 〈 0.05）. Cerebral hemorrhage reached a peak at 24 hours after injury, and the degree of brain edema was maximal at 168 hours after injury. WBC and PMN counts were positively correlated to cerebral hemorrhage volume and brain edema size （P 〈 0.05）. CONCLUSION： WBC and PMN counts significantly increased after craniocerebral injury and exhibited a correlation with the GCS score, volume of hemorrhage and edema, and Glasgow outcome scale.

Interactions of primary insult biomechanics and secondary cascades in spinal cord injury： implications for therapy

The complex and variable nature of traumatic spinal cord inju- ry （SCI） presents a unique challenge for translational research. SCI is not bound by any demographic nor is it limited to specific injury biomechanics.

Neutrophil-derived interleukin-17A participates in neuroinflammation induced by traumatic brain injury

After brain injury, infiltration and abnormal activation of neutrophils damages brain tissue and worsens inflammation, but the mediators that connect activated neutrophils with neuroinflammation have not yet been fully clarified. To identify regulators of neutrophil-mediated neuroinflammation after traumatic brain injury, a mouse model of traumatic brain injury was established by controlled cortical impact. At 7 days post-injury(sub-acute phase), genome-wide transcriptomic data showed that interleukin 17 A-associated signaling pathways were markedly upregulated, suggesting that interleukin 17 A may be involved in neuroinflammation. Double immunofluorescence staining showed that interleukin 17 A was largely secreted by neutrophils rather than by glial cells and neurons. Furthermore, nuclear factor-kappaB and Stat3, both of which are important effectors in interleukin 17 A-mediated proinflammatory responses, were significantly activated. Collectively, our findings suggest that neutrophil-derived interleukin 17 A participates in neutrophil-mediated neuroinflammation during the subacute phase of traumatic brain injury. Therefore, interleukin 17 A may be a promising therapeutic target for traumatic brain injury.

Changes in platelet parameters and secondary brain injury in acute craniocerebral trauma

Changes in platelet parameters are important in secondary brain injury in acute craniocerebral trauma We selected 163 patients with craniocerebral trauma who were admitted within 24 hours with nonoperative therapy. Platelet parameters of 40 healthy subjects served as controls. Platelet number was decreased, while mean platelet volume and platelet distribution width values were increased, at 1 and 3 days after injury. Platelet number was lower and mean platelet volume and platelet distribution width were larger in patients with traumatic cerebral infarction and those in Glasgow Coma Scale score 〈 8 group. Platelet number was negatively correlated to volume of cerebral edema, but positively correlated to Glasgow Outcome Scale score. These data indicate that changes in platelet parameters may be utilized to indicate the state of central nervous system injury and patient prognosis .

Effects of low dose Glibenclamide on secondary damage after acute spinal cord injury in rats

Objective To investigate the effects of Glibenclamide on reduction of secondary damage after acute spinal cord injury in rats.Methods Ninety rats were randomly divided into control group(laminectomy alone),spinal cord injury group(injury group),and treatment group(treated

T cell interactions with microglia in immune-inflammatory processes of ischemic stroke

The primary mechanism of secondary injury after cerebral ischemia may be the brain inflammation that emerges after an ischemic stroke,which promotes neuronal death and inhibits nerve tissue regeneration.As the first immune cells to be activated after an ischemic stroke,microglia play an important immunomodulatory role in the progression of the condition.After an ischemic stroke,peripheral blood immune cells(mainly T cells)are recruited to the central nervous system by chemokines secreted by immune cells in the brain,where they interact with central nervous system cells(mainly microglia)to trigger a secondary neuroimmune response.This review summarizes the interactions between T cells and microglia in the immune-inflammatory processes of ischemic stroke.We found that,during ischemic stroke,T cells and microglia demonstrate a more pronounced synergistic effect.Th1,Th17,and M1 microglia can co-secrete proinflammatory factors,such as interferon-γ,tumor necrosis factor-α,and interleukin-1β,to promote neuroinflammation and exacerbate brain injury.Th2,Treg,and M2 microglia jointly secrete anti-inflammatory factors,such as interleukin-4,interleukin-10,and transforming growth factor-β,to inhibit the progression of neuroinflammation,as well as growth factors such as brain-derived neurotrophic factor to promote nerve regeneration and repair brain injury.Immune interactions between microglia and T cells influence the direction of the subsequent neuroinflammation,which in turn determines the prognosis of ischemic stroke patients.Clinical trials have been conducted on the ways to modulate the interactions between T cells and microglia toward anti-inflammatory communication using the immunosuppressant fingolimod or overdosing with Treg cells to promote neural tissue repair and reduce the damage caused by ischemic stroke.However,such studies have been relatively infrequent,and clinical experience is still insufficient.In summary,in ischemic stroke,T cell subsets and activated microglia act synergistically to regulate inflammatory progression,mainly by secreting inflammatory factors.In the future,a key research direction for ischemic stroke treatment could be rooted in the enhancement of anti-inflammatory factor secretion by promoting the generation of Th2 and Treg cells,along with the activation of M2-type microglia.These approaches may alleviate neuroinflammation and facilitate the repair of neural tissues.

Piezo1 as a potential player in intracranial hemorrhage:From perspectives on biomechanics and hematoma metabolism

Intracranial hemorrhage(ICH)causes numerous neurological deficits and deaths worldwide each year,leaving a significant health burden on the public.The pathophysiology of ICH is complicated and involves both primary and secondary injuries.Hematoma,as the primary pathology of ICH,undergoes metabolism and triggers biochemical and biomechanical alterations in the brain,leading to the secondary injury.Past endeavors mainly aimed at biochemical-initiated mechanisms for causing secondary injury,which have made limited progress in recent years,although ICH itself is also highly biomechanics-related.The discovery of the mechanically-activated cation channel Piezo1 provides a new avenue to further explore the mechanisms underlying the secondary injury.The current article reviews the structure and gating mechanisms of Piezo1,its roles in the physiology/pathophysiology of neurons,astrocytes,microglia,and bone-marrow-derived macrophages,and especially its roles in erythrocytic turnover and iron metabolism,revealing a potential interplay between the biomechanics and biochemistry of hematoma in ICH.Collectively,these advances provide deeper insights into the secondary injury of ICH and lay the foundations for future research.

Mitophagy in intracerebral hemorrhage:a new target for therapeutic intervention

Intracerebral hemorrhage is a life-threatening condition with a high fatality rate and severe sequelae.However,there is currently no treatment available for intracerebral hemorrhage,unlike for other stroke subtypes.Recent studies have indicated that mitochondrial dysfunction and mitophagy likely relate to the pathophysiology of intracerebral hemorrhage.Mitophagy,or selective autophagy of mitochondria,is an essential pathway to preserve mitochondrial homeostasis by clearing up damaged mitochondria.Mitophagy markedly contributes to the reduction of secondary brain injury caused by mitochondrial dysfunction after intracerebral hemorrhage.This review provides an overview of the mitochondrial dysfunction that occurs after intracerebral hemorrhage and the underlying mechanisms regarding how mitophagy regulates it,and discusses the new direction of therapeutic strategies targeting mitophagy for intracerebral hemorrhage,aiming to determine the close connection between mitophagy and intracerebral hemorrhage and identify new therapies to modulate mitophagy after intracerebral hemorrhage.In conclusion,although only a small number of drugs modulating mitophagy in intracerebral hemorrhage have been found thus far,most of which are in the preclinical stage and require further investigation,mitophagy is still a very valid and promising therapeutic target for intracerebral hemorrhage in the long run.

Lithium promotes recovery of neurological function after spinal cord injury by inducing autophagy

Lithium promotes autophagy and has a neuroprotective effect on spinal cord injury（SCI）; however, the underlying mechanisms remain unclear. Therefore, in this study, we investigated the effects of lithium and the autophagy inhibitor 3-methyladenine（3-MA） in a rat model of SCI. The rats were randomly assigned to the SCI, lithium, 3-MA and sham groups. In the 3-MA group, rats were intraperitoneally injected with 3-MA（3 mg/kg） 2 hours before SCI. In the lithium and 3-MA groups, rats were intraperitoneally injected with lithium（LiCl; 30 mg/kg） 6 hours after SCI and thereafter once daily until sacrifice. At 2, 3 and 4 weeks after SCI, neurological function and diffusion tensor imaging indicators were remarkably improved in the lithium group compared with the SCI and 3-MA groups. The Basso, Beattie and Bresnahan locomotor rating scale score and fractional anisotropy values were increased, and the apparent diffusion coefficient value was decreased. Immunohistochemical staining showed that immunoreactivities for Beclin-1 and light-chain 3 B peaked 1 day after SCI in the lithium and SCI groups. Immunoreactivities for Beclin-1 and light-chain 3 B were weaker in the 3-MA group than in the SCI group, indicating that 3-MA inhibits lithium-induced autophagy. Furthermore, NeuN＋ neurons were more numerous in the lithium group than in the SCI and 3-MA groups, with the fewest in the latter. Our findings show that lithium reduces neuronal damage after acute SCI and promotes neurological recovery by inducing autophagy. The neuroprotective mechanism of action may not be entirely dependent on the enhancement of autophagy, and furthermore, 3-MA might not completely inhibit all autophagy pathways.

Sodium selenite promotes neurological function recovery after spinal cord injury by inhibiting ferroptosis

Ferroptosis is a recently discovered form of iron-dependent cell death,which occurs during the pathological process of various central nervous system diseases or injuries,including secondary spinal cord injury.Selenium has been shown to promote neurological function recovery after cerebral hemorrhage by inhibiting ferroptosis.However,whether selenium can promote neurological function recovery after spinal cord injury as well as the underlying mechanism remain poorly understood.In this study,we injected sodium selenite(3μL,2.5μM)into the injury site of a rat model of T10 vertebral contusion injury 10 minutes after spinal cord injury modeling.We found that sodium selenite treatment greatly decreased iron concentration and levels of the lipid peroxidation products malondialdehyde and 4-hydroxynonenal.Furthermore,sodium selenite increased the protein and mRNA expression of specificity protein 1 and glutathione peroxidase 4,promoted the survival of neurons and oligodendrocytes,inhibited the proliferation of astrocytes,and promoted the recovery of locomotive function of rats with spinal cord injury.These findings suggest that sodium selenite can improve the locomotive function of rats with spinal cord injury possibly through the inhibition of ferroptosis via the specificity protein 1/glutathione peroxidase 4 pathway.

Current therapeutic strategies for inflammation following traumatic spinal cord injury

Damage from spinal cord injury occurs in two phases-the trauma of the initial mechanical insult and a secondary injury to nervous tissue spared by the primary insult.Apart from damage sustained as a result of direct trauma to the spinal cord,the post-traumatic inflammatory response contributes significantly to functional motor deficits exacerbated by the secondary injury.Attenuating the detrimental aspects of the inflammatory response is a promising strategy to potentially ameliorate the secondary injury,and promote significant functional recovery.This review details how the inflammatory component of secondary injury to the spinal cord can be treated currently and in the foreseeable future.

Comparative transcriptomic analysis of rat versus mouse cerebral cortex after traumatic brain injury

The heterogeneity of traumatic brain injury(TBI)-induced secondary injury has greatly hampered the development of effective treatments for TBI patients.Targeting common processes across species may be an innovative strategy to combat debilitating TBI.In the present study, a cross-species transcriptome comparison was performed for the first time to determine the fundamental processes of secondary brain injury in Sprague-Dawley rat and C57/BL6 mouse models of TBI, caused by acute controlled cortical impact.The RNA sequencing data from the mouse model of TBI were downloaded from the Gene Expression Omnibus(ID: GSE79441) at the National Center for Biotechnology Information.For the rat data, peri-injury cerebral cortex samples were collected for transcriptomic analysis 24 hours after TBI.Differentially expressed gene-based functional analysis revealed that common features between the two species were mainly involved in the regulation and activation of the innate immune response, including complement cascades as well as Toll-like and nucleotide oligomerization domain-like receptor pathways.These findings were further corroborated by gene set enrichment analysis.Moreover, transcription factor analysis revealed that the families of signal transducers and activators of transcription(STAT), basic leucine zipper(BZIP), Rel homology domain(RHD), and interferon regulatory factor(IRF) transcription factors play vital regulatory roles in the pathophysiological processes of TBI, and are also largely associated with inflammation.These findings suggest that targeting the common innate immune response might be a promising therapeutic approach for TBI.The animal experimental procedures were approved by the Beijing Neurosurgical Institute Animal Care and Use Committee(approval No.201802001) on June 6, 2018.