Ferroptosis inhibition protects vascular endothelial cells and maintains integrity of the blood-spinal cord barrier after spinal cord injury

Maintaining the integrity of the blood-spinal cord barrier is critical for the recove ry of spinal cord injury.Ferro ptosis contributes to the pathogenesis of spinal cord injury.We hypothesized that ferroptosis is involved in disruption of the blood-s pinal cord barrier.In this study,we administe red the ferroptosis inhibitor liproxstatin-1 intraperitoneally after contusive spinal co rd injury in rats.Liproxstatin-1 improved locomotor recovery and somatosensory evoked potential electrophysiological performance after spinal cord inju ry.Liproxstatin-1 maintained blood-spinal cord barrier integrity by upregulation of the expression of tight junction protein.Liproxstatin-1 inhibited ferroptosis of endothelial cell after spinal cord injury,as shown by the immunofluorescence of an endothelial cell marker(rat endothelium cell antigen-1,RECA-1) and fe rroptosis markers Acyl-CoA synthetase long-chain family member 4 and 15-lipoxygenase.Liproxstatin-1reduced brain endothelial cell ferroptosis in vitro by upregulating glutathione peroxidase 4 and downregulating Acyl-CoA synthetase long-chain family member4 and 15-lipoxygenase.Furthermore,inflammatory cell recruitment and astrogliosis were mitigated after liproxstatin-1 treatment.In summary,liproxstatin-1im proved spinal cord injury recovery by inhibiting ferroptosis in endothelial cells and maintaining blood-s pinal co rd barrier integrity.

Baicalin attenuates blood-spinal cord barrier disruption and apoptosis through PI3K/Akt signaling pathway after spinal cord injury

Baicalin is a natural active ingredient isolated from Scutellariae Radix that can cross the blood-brain barrier and exhibits neuroprotective effects on multiple central nervous system diseases.However,the mechanism behind the neuroprotective effects remains unclear.In this study,rat models of spinal cord injury were established using a modified Allen's impact method and then treated with intraperitoneal injection of Baicalin.The results revealed that Baicalin greatly increased the Basso,Beattie,Bresnahan Locomotor Rating Scale score,reduced blood-spinal cord barrier permeability,decreased the expression of Bax,Caspase-3,and nuclear factorκB,increased the expression of Bcl-2,and reduced neuronal apoptosis and pathological spinal cord injury.SH-SY5 Y cell models of excitotoxicity were established by application of 10 m M glutamate for 12 hours and then treated with 40μM Baicalin for 48 hours to investigate the mechanism of action of Baicalin.The results showed that Baicalin reversed tight junction protein expression tendencies(occludin and ZO-1)and apoptosis-related protein expression(Bax,Bcl-2,Caspase-3,and nuclear factor-κB),and also led to up-regulation of PI3 K and Akt phosphorylation.These effects on Bax,Bcl-2,and Caspase-3 were blocked by pretreatment with the PI3 K inhibitor LY294002.These findings suggest that Baicalin can inhibit bloodspinal cord barrier permeability after spinal cord injury and reduce neuronal apoptosis,possibly by activating the PI3 K/Akt signaling pathway.This study was approved by Animal Ethics Committee of Xi'an Jiaotong University on March 6,2014.

Transactivating-transduction protein-polyethylene glycol modified liposomes traverse the blood-spinal cord and blood-brain barriers

Naive liposomes can cross the blood-brain barrier and blood-spinal cord barrier in small amounts. Liposomes modified by a transactivating-transduction protein can deliver antibiotics for the treatment of acute bacterial infection-induced brain inflammation. Liposomes conjugated with polyethylene glycol have the capability of long-term circulation. In this study we prepared transactivating-transduction protein-polyethylene glycol-modified liposomes labeled with fiuorescein isothiocyanate. Thus, liposomes were characterized by transmembrane, long-term circulation and fluorescence tracing. Uptake, cytotoxicity, and the ability of traversing blood-spinal cord and blood-brain barriers were observed following coculture with human breast adenocarcinoma cells （MCF-7）. Results demonstrated that the liposomes had good biocompatibility, and low cytotoxicity when cocultured with human breast adenocarcinoma cells. Liposomes could traverse cell membranes and entered the central nervous system and neurocytes through the blood-spinal cord and blood-brain barriers of rats via the systemic circulation. These results verified that fluorescein isothiocyanate-modified transactivating-transduction protein-polyethylene glycol liposomes have the ability to traverse the blood-spinal cord and blood-brain barriers.

Morphological and functional changes in the blood-spinal cord barrier of rabbits in an experimental spinal cord presyrinx state

BACKGROUND: Presyrinx state of spinal cord can reflect the initial lesion of syringomyelia (SM). The early trials has proved that ischamia and edema are main pathological changes of presyrinx state. OBJECTIVE: To establish SM model of rabbits for investigating the relationship between changes of morphous and function of blood-spinal cord barrier and the edema degree, histological changes in presyrinx state of SM, and to explore the mechanism of the presyrinx state of SM. DESIGN: Randomized controlled animal experiment. SETTING: Department of Neurosurgery, Fourth Hospital, Heibei Medical University. MATERIALS: Sixty Chinese healthy white rabbits, aged 3.5-4.5 months, weighing 1.5-2.0 kg, were provided by Experimental Animal Center of Hebei Medical University [certification: (SYXK(Ji)2003-0026)]. Evan's blue (EB) and dimethylformamide (DMF) were purchased from Jingmei Biotech Co., Ltd. RM2125 paraffin section cutter (Leica Company, Japan), H-7500 transmission electron microscope (Hitachi Company, Japan), PM-20 light microscope photograph system (Olympus Company, Japan). METHODS: The experiment was carried out in the Laboratory of Neurosurgery Department, Second Hospital of Hebei Medical University from January to June 2006. ① All the rabbits were randomly divided into two groups: model group (n =40), control group (n =20). Rabbits in two groups were divided into five subgroups once again at five time points (1st, 3rd, 7th, 14th, 21st days, n =8 and n =4 at each time point in the model group and control group, respectively). Under ketamine anesthesia, 0.6 mL Kaolin solution (250 g/L, 37 ℃) was injected into the cisterna magna of rabbits in model group, while 0.6 mL physiological saline (37 ℃) was injected into the rabbits of control group. ② On the 1st, 3rd, 7th, 14th, 21st days after kaolin injection, cervical cord samples were harvested after sacrifice of animal. Quantitative analysis on the function of blood-spinal cord barrier was performed by Evan's blue technique. Water content of spinal cord was measured by dry-wet weighing technique. Samples were fixed in 40 g/L paraform for haematoxylin and eosin staining. Pathological and ultramicrostructural observation was carried out under a light microscope and H-7500 electron microscope, respectively. ③ The comparison of measurement data was performed with analysis of variance. MAIN OUTCOME MEASURES: The changes of water content, Evan's blue content and pathology in upper cervical cord of presyrinx state at different time points. RESULTS: All the 60 rabbits were involved in the result analysis. ① Ultramicrostructural observation: During the whole process of occurrence and development of presyrinx state of spinal cord, no obvious morphological changes of blood-spinal cord barrier were found. Microvascular endothelial cells were in integrity in morphology, basal membrane was continuous and smooth, and the structure of tight junction was not destructed remarkably. ②Water content of spinal cord: Compared with control group, the water content of spinal cord was increased on the 1st day [(68.35±0.7)% vs.(66.51±0.32)%, F =7.387, P =0.026] after kaolin injection, more prominent on the 3rd day [(72.70±0.88)%, F =123.48, P =0.000], reached its peak on the 7th-14th day [(72.92±0.86)%, F =135.94, P =0.000; (72.18±0.55)%, F =28.18, P =0.001], and was declined slowly after 21 days[(70.03±0.77)%,F =11.51, P =0.009], but it was still higher than that of control group [(65.98±0.56)%, F = 11.51, P =0.009].③ Evan's blue content in spinal cord tissue: It started to rise on the 3rd day after operation [(2.79±0.42) mg/L, F =61.35, P =0.000], reached its peak on the 7th day [(3.53±0.45) mg/L, F =528.35, P =0.000], and kept this high level till the 14th day [(3.45± 0.35) mg/L, F =326.57, P =0.000]. It decreased on the 21st day [(3.36±0.27) mg/L], but was still higher than normal level[(1.69±0.16)mg/L,F = 58.63,P =0.000]. ④ Neurologic function score: The neurologic function score of rabbits in the model group was close to that in the control group preoperatively and on the postoperative 1st and 3rd days (F =2.667, P =0.141);Abnormal nerve function appeared on the postoperative 7th day (F =32.667, P =0.00), and the neurologic function scores were gradually decreased with the elongation of time. The neurologic function scores in the model group were significantly lower than those in the control group on the postoperative 14th and 21st days (F =42.667, 34.571,P =0.00). CONCLUSION: Under the presyrinx state of spinal cord of experimental rabbits, the destruction of blood-spinal cord barrier of spinal cord and spinal edema co-exist with the same changing tendency. Although morphological integrity of blood-spinal cord barrier is kept, the function of blood-spinal cord barrier was destroyed in the early stage and permeability is increased. This functional disorder plays an important role in the occurrence and development of presyrinx state of SM.

Pharmacological interventions targeting the microcirculation following traumatic spinal cord injury

Traumatic spinal cord injury is a devastating disorder chara cterized by sensory,motor,and autonomic dysfunction that seve rely compromises an individual's ability to perform activities of daily living.These adve rse outcomes are closely related to the complex mechanism of spinal cord injury,the limited regenerative capacity of central neurons,and the inhibitory environment fo rmed by traumatic injury.Disruption to the microcirculation is an important pathophysiological mechanism of spinal cord injury.A number of therapeutic agents have been shown to improve the injury environment,mitigate secondary damage,and/or promote regeneration and repair.Among them,the spinal cord microcirculation has become an important target for the treatment of spinal cord injury.Drug inte rventions targeting the microcirculation can improve the microenvironment and promote recovery following spinal cord injury.These drugs target the structure and function of the spinal cord microcirculation and are essential for maintaining the normal function of spinal neuro ns,axons,and glial cells.This review discusses the pathophysiological role of spinal cord microcirculation in spinal cord injury,including its structure and histopathological changes.Further,it summarizes the progress of drug therapies targeting the spinal cord mic rocirc ulation after spinal cord injury.

Mertk Reduces Blood-Spinal Cord Barrier Permeability Through the Rhoa/Rock1/P-MLC Pathway After Spinal Cord Injury

Disruption of the blood-spinal cord barrier(BSCB)is a critical event in the secondary injury following spinal cord injury(SCI).Mertk has been reported to play an important role in regulating inflammation and cytoskeletal dynamics.However,the specific involvement of Mertk in BSCB remains elusive.Here,we demonstrated a distinct role of Mertk in the repair of BSCB.Mertk expression is decreased in endothelial cells following SCI.Overexpression of Mertk upregulated tight junction proteins(TJs),reducing BSCB permeability and subsequently inhibiting inflammation and apoptosis.Ultimately,this led to enhanced neural regeneration and functional recovery.Further experiments revealed that the RhoA/Rock1/P-MLC pathway plays a key role in the effects of Mertk.These findings highlight the role of Mertk in promoting SCI recovery through its ability to mitigate BSCB permeability and may provide potential targets for SCI repair.

ABC efflux transporters at blood-central nervous system barriers and their implications for treating spinal cord disorders

The barriers present in the interfaces between the blood and the central nervous system form a major hurdle for the pharmacological treatment of central nervous system injuries and diseases.The family of ATP-binding cassette(ABC)transporters has been widely studied regarding efflux of medications at blood-central nervous system barriers.These efflux transporters include P-glycoprotein(abcb1),‘breast cancer resistance protein'(abcg2)and the various‘multidrug resistance-associated proteins'(abccs).Understanding which efflux transporters are present at the blood-spinal cord,blood-cerebrospinal fluid and cerebrospinal fluid-spinal cord barriers is necessary to determine their involvement in limiting drug transfer from blood to the spinal cord tissue.Recent developments in the blood-brain barrier field have shown that barrier systems are dynamic and the profile of barrier defenses can alter due to conditions such as age,disease and environmental challenge.This means that a true understanding of ABC efflux transporter expression and localization should not be one static value but instead a range that represents the complex patient subpopulations that exist.In the present review,the blood-central nervous system barrier literature is discussed with a focus on the impact of ABC efflux transporters on:(i)protecting the spinal cord from adverse effects of systemically directed drugs,and(ii)limiting centrally directed drugs from accessing their active sites within the spinal cord.

Reviving the use of inhibitors of matrix metalloproteases in spinal cord injury:a case for specificity

At present,there are no resto rative therapies in the clinic for spinal cord injury,with current treatments offering only palliative treatment options.The role of matrix metalloproteases is well established in spinal cord injury,howeve r,translation into the clinical space was plagued by early designs of matrix metalloprotease inhibitors that lacked specificity and fears of musculos keletal syndrome prevented their further development.Newe r,much more specific matrix metalloprotease inhibitors have revived the possibility of using these inhibitors in the clinic since they are much more specific to their to rget matrix metalloproteases.Here,the evidence for use of matrix metalloproteases after spinal cord injury is reviewed and researche rs are urged to overcome their old fears rega rding matrix metalloprotease inhibition and possible side effects for the field to progress.Recently published work by us shows that inhibition of specific matrix metalloproteases after spinal cord injury holds promise since four key consequences of spinal cord injury could be alleviated by specific,next-gene ration matrix metalloprotease inhibitors.For example,specific inhibition of matrix metalloprotease-9 and matrix metalloprotease-12 within 24 hours after injury and for 3 days,alleviates spinal cord injury-induced edema,blood-s pinal co rd barrier breakdown,neuro pathic pain and resto res sensory and locomotor function.Attempts are now underway to translate this therapy into the clinic.

Exosomes derived from bone marrow mesenchymal stem cells protect the injured spinal cord by inhibiting pericyte pyroptosis

Mesenchymal stem cell(MSC)transplantation is a promising treatment strategy for spinal cord injury,but immunological rejection and possible tumor formation limit its application.The therapeutic effects of MSCs mainly depend on their release of soluble paracrine factors.Exosomes are essential for the secretion of these paracrine effectors.Bone marrow mesenchymal stem cell-derived exosomes(BMSC-EXOs)can be substituted for BMSCs in cell transplantation.However,the underlying mechanisms remain unclear.In this study,a rat model of T10 spinal cord injury was established using the impact method.Then,30 minutes and 1 day after spinal cord injury,the rats were administered 200μL exosomes via the tail vein(200μg/mL;approximately 1×106 BMSCs).Treatment with BMSC-EXOs greatly reduced neuronal cell death,improved myelin arrangement and reduced myelin loss,increased pericyte/endothelial cell coverage on the vascular wall,decreased bloodspinal cord barrier leakage,reduced caspase 1 expression,inhibited interleukin-1βrelease,and accelerated locomotor functional recovery in rats with spinal cord injury.In the cell culture experiment,pericytes were treated with interferon-γand tumor necrosis factor-α.Then,Lipofectamine 3000 was used to deliver lipopolysaccharide into the cells,and the cells were co-incubated with adenosine triphosphate to simulate injury in vitro.Pre-treatment with BMSC-EXOs for 8 hours greatly reduced pericyte pyroptosis and increased pericyte survival rate.These findings suggest that BMSC-EXOs may protect pericytes by inhibiting pyroptosis and by improving blood-spinal cord barrier integrity,thereby promoting the survival of neurons and the extension of nerve fibers,and ultimately improving motor function in rats with spinal cord injury.All protocols were conducted with the approval of the Animal Ethics Committee of Zhengzhou University on March 16,2019.

Role of hypoxia-induced VEGF in blood-spinal cord barrier disruption in chronic spinal cord injury

Chronic spinal cord lesions （CSCL） which result in irreversible neurologic deficits remain one of tbe most devastating clinical problems. Its patbophysiological mechanism has not been fully clarified. As a crucial factor in the outcomes following traumatic spinal cord injury （SCI）, the blood-spinal cord barrier （BSCB） disruption is considered as an important pathogenic factor contributing to the neurologic impairment in SCI. Vascular endothelial growth factor （VEGF） is a multirole element in the spinal cord vascular event. On one hand, VEGF administrations can result in rise of BSCB permeability in acute or sub-acute periods and even last for chronic process. On the other band, VEGF is regarded to be correlated with anglo- genesis, neurogenesis and improvement of locomotor ability. Hypoxia inducible factor-I （HIFq） is a primary regulator of VEGF during hypoxic conditions. Therefore, hypoxia-mediated up-regulation of VEGF may play multiple roles in the BSCB disruption and react on functional restoration of CSCL. The purpose of this article is to further explore the relationship among HIF-1, hypoxia-mediated VEGF and BSCB dysfunction, and investigate the roles of these elements on CSCL.

Elevated intraspinal pressure in traumatic spinal cord injury is a promising therapeutic target

The currently recommended management for acute traumatic spinal cord injury aims to reduce the incidence of secondary injury and promote functional recovery.Elevated intraspinal pressure(ISP)likely plays an important role in the processes involved in secondary spinal cord injury,and should not be overlooked.However,the factors and detailed time course contributing to elevated ISP and its impact on pathophysiology after traumatic spinal cord injury have not been reviewed in the literature.Here,we review the etiology and progression of elevated ISP,as well as potential therapeutic measures that target elevated ISP.Elevated ISP is a time-dependent process that is mainly caused by hemorrhage,edema,and blood-spinal cord barrier destruction and peaks at 3 days after traumatic spinal cord injury.Duraplasty and hypertonic saline may be promising treatments for reducing ISP within this time window.Other potential treatments such as decompression,spinal cord incision,hemostasis,and methylprednisolone treatment require further validation.

Exogenous platelet-derived growth factor improves neurovascular unit recovery after spinal cord injury

The blood-spinal cord barrier plays a vital role in recovery after spinal cord injury.The neurovascular unit concept emphasizes the relationship between nerves and vessels in the brain,while the effect of the blood-spinal cord barrier on the neurovascular unit is rarely reported in spinal cord injury studies.Mouse models of spinal cord injury were established by heavy object impact and then immediately injected with plateletderived growth factor(80μg/kg)at the injury site.Our results showed that after platelet-derived growth factor administration,spinal cord injury,neuronal apoptosis,and blood-spinal cord barrier permeability were reduced,excessive astrocyte proliferation and the autophagyrelated apoptosis signaling pathway were inhibited,collagen synthesis was increased,and mouse locomotor function was improved.In vitro,human umbilical vein endothelial cells were established by exposure to 200μM H2O2.At 2 hours prior to injury,in vitro cell models were treated with 5 ng/mL platelet-derived growth factor.Our results showed that expression of blood-spinal cord barrier-related proteins,including Occludin,Claudin 5,andβ-catenin,was significantly decreased and autophagy was significantly reduced.Additionally,the protective effects of platelet-derived growth factor could be reversed by intraperitoneal injection of 80 mg/kg chloroquine,an autophagy inhibitor,for 3 successive days prior to spinal cord injury.Our findings suggest that platelet-derived growth factor can promote endothelial cell repair by regulating autophagy,improve the function of the blood-spinal cord barrier,and promote the recovery of locomotor function post-spinal cord injury.Approval for animal experiments was obtained from the Animal Ethics Committee,Wenzhou Medical University,China(approval No.wydw2018-0043)in July 2018.

The roles of microRNAs in spinal cord ischemia-reperfusion injury

Spinal cord ischemia/reperfusion injury is a devastating medical disorder with poor prognosis that is associated with several pathophysiological conditions.However,multiple stimuli can trigger SCII,so the underlying mechanism of this pathology has not yet been fully established.MicroRNAs(miRNAs)are a class of non-coding RNAs that mediate a variety of nervous system diseases and regulate numerous physiological functions,including apoptosis,autophagy,inflammation,and blood-spinal cord barrier damage.miRNA expression profiles are known to be altered after spinal cord ischemia/reperfusion injury.Therefore,gaining a better understanding of the significant roles that miRNAs play in spinal cord ischemia/reperfusion injury could help develop potential preventive and therapeutic strategies for spinal cord ischemia/reperfusion injury.This review summarizes the current state of our knowledge about the relationship between miRNAs and spinal cord ischemia/reperfusion injury,as well as potential miRNAs that could be targeted to treat spinal cord ischemia/reperfusion injury.

Dynamic changes in intramedullary pressure 72 hours after spinal cord injury

Intramedullary pressure increases after spinal cord injury, and this can be an important factor for secondary spinal cord injury. Until now there have been no studies of the dynamic changes of intramedullary pressure after spinal cord injury. In this study, telemetry systems were used to observe changes in intramedullary pressure in the 72 hours following spinal cord injury to explore its pathological mechanisms. Spinal cord injury was induced using an aneurysm clip at T10 of the spinal cord of 30 Japanese white rabbits, while another 32 animals were only subjected to laminectomy. The feasibility of this measurement was assessed. Intramedullary pressure was monitored in anesthetized and conscious animals. The dynamic changes of intramedullary pressure after spinal cord injury were divided into three stages: stage I(steep rise) 1–7 hours, stage Ⅱ(steady rise) 8–38 hours, and stage Ⅲ(descending) 39–72 hours. Blood-spinal barrier permeability, edema, hemorrhage, and histological results in the 72 hours following spinal cord injury were evaluated according to intramedullary pressure changes. We found that spinal cord hemorrhage was most severe at 1 hour post-spinal cord injury and then gradually decreased; albumin and aquaporin 4 immunoreactivities first increased and then decreased, peaking at 38 hours. These results confirm that severe bleeding in spinal cord tissue is the main cause of the sharp increase in intramedullary pressure in early spinal cord injury. Spinal cord edema and blood-spinal barrier destruction are important factors influencing intramedullary pressure in stages Ⅱ and Ⅲ of spinal cord injury.

多功能阳离子脂质体跨血脊髓屏障的实验研究

目的探讨异硫氰酸荧光素（FITC）标记阳离子脂质体通过尾静脉注入后,跨越大鼠血脊髓屏障并在局部聚集的情况。方法 30只成年Wistar大鼠随机等分为3组,每组10只,荧光显微镜动态观察脂质体在中枢神经系统（CNS）中靶向聚集与扩散情况,通过组织学观测进一步分析其与CNS细胞的关系。结果相同浓度下（75-600μg/m L）,TAT-PEG-阳离子脂质体较未经TAT修饰者具更低细胞毒性,且更易被MCF-7细胞摄取;FITC标记TAT-PEG-阳离子脂质体可跨越BSCB并聚集,低倍镜下观察到许多荧光微粒聚集于CNS组织,高倍镜形象地显示出荧光微粒位于神经细胞内。结论经跨膜肽（TAT）、聚乙二醇（PEG）修饰的阳离子脂质体具有良好的生物相容性与靶向定位特性,可跨过BSCB,聚集于CNS细胞中,安全用作药物载体,为中枢神经系统疾病的治疗提供新的途径。

利用外源性IgG显示大鼠脊髓撞击伤后血-脊髓屏障变化

血-脑(脊髓)屏障损伤范围的观察方法多为注射外源性示踪剂,我们曾在大鼠实验中采用内源性血浆IgG作为示踪剂,取得很好的效果。本研究在大鼠脊髓撞击伤模型中以静脉注射的兔IgG为外源性示踪剂,用免疫荧光双标显示并比较了大鼠与兔两种IgG在脊髓内的分布。用图像阈值分割技术处理图像后,分析了损伤后不同时间点(0h,1d,3d,5d,7d,14d)两者的异同,发现在血-脊髓屏障已恢复的部位仍有残留的内源性IgG,而外源性IgG可精确地反映注射当时血-脊髓屏障的改变。这种方法可有效地用于诸如不同药物保护血-脑屏障的时程研究。

糖尿病介导的周细胞损伤对脊髓损伤后血脊屏障破坏的作用

糖尿病是一种常见的慢性代谢异常性疾病,可通过血糖异常诱导体内内环境紊乱,引起一系列急性或慢性并发症。慢性高血糖可引起大血管和微血管病变,该过程由错综复杂的分子机制协同调控,例如炎症反应、细胞内应激作用、细胞焦亡和细胞铁死亡等。糖尿病可抑制脊髓损伤后血脊屏障修复,加重神经功能损伤,从而不利于运动功能恢复。周细胞是神经血管单元的重要组成部分,参与调控血管再生、毛细血管血流量以及血脊屏障渗透性。脊髓损伤后,血脊屏障遭到破坏,周细胞覆盖率显著降低,血管正常功能受到巨大影响。糖尿病不仅参与调控周细胞的收缩表型和信号传导,而且改变周细胞分泌基因组谱,影响周细胞正常功能。此外,有研究证实,糖尿病促进脊髓损伤后周细胞丢失。本综述系统阐述了糖尿病对血管系统中周细胞的调控作用,及其介导的周细胞损伤对脊髓损伤后血脊屏障修复影响的研究进展。

Microvascular protective role of pericytes in melatonin-treated spinal cord injury in the C57BL/6 mice

Background Pericytes,located on microvessels,help to maintain vascular stability and blood-brain barrier integrity.The influence of pericytes on microvessels after spinal cord injury （SCI） is less clear.Therefore,the aim of this study was to investigate whether pericytes took a protective effect on microvessels in melatonin-treated SCI.Methods C57BL/6 mice were randomly divided into three groups：sham group,SCI group,and melatonin group （n=27per group）.Functional recovery was evaluated using the Basso Mouse Scale.Motor neurons were observed using hematoxylin and eosin staining.Pericyte coverage was analyzed using immunofluorescence.Permeability of blood-spinal cord barrier （BSCB） was assessed by administration of Evan＇s Blue.Protein levels of occludin,aquaporin-4 （AQP4）,angiopoietin-1 （Ang1）,intercellular cell adhesion molecule-1 （ICAM-1）,Bcl-2,and Bax were determined using Western blotting.Mimicking the pathological conditions of SCI,melatonin-treated primary pericytes were subjected to oxygenglucose deprivation/reperfusion （OGD/R）.Secretion of Ang1 was analyzed using an enzyme-linked immunosorbent assay,and the expression of ICAM-1 was detected by immunofluorescence.Results Melatonin treatment improved locomotor functional outcome and rescued motor neurons.Pericyte coverage was significantly reduced after SCI; melatonin treatment alleviated the loss of pericyte coverage and rescued perfused microvessels 7 days after injury.The permeability of BSCB and loss of occludin were attenuated,and edema formation and upregulation of AQP4 were inhibited,after melatonin treatment.The expression of Ang1 and Bcl-2 was improved,while the expression of ICAM-1 and Bax was inhibited,in melatonin-treated SCl mice.Furthermore,the secretion of Ang1 was increased and the expression of ICAM-1 was inhibited in melatonin-treated pericytes after OGD/R.Conclusions Melatonin ameliorated the loss of blood vessels and disruption of BSCB to exert a protective effect on SCI,which might be mediated by increased pericyte coverage.The upregulation of Ang1 in pericytes could inhibit inflammation and apoptosis to protect the microvessels.

活血通督汤对大鼠脊髓损伤后血-脊髓屏障的修复作用

目的:通过对大鼠脊髓损伤(SCI)后的行为学评分、脊髓组织病理分析以及血-脊髓屏障(BSCB)功能的评测,观察活血通督汤对大鼠SCI后BSCB的影响。方法:将24只雌性SD大鼠随机均分为假手术组、模型组及活血通督汤组,每组8只。假手术组仅咬除椎板不损伤脊髓,模型组和活血通督汤组采用改良Allen’s法建立SCI模型。分别于第1、3、5、7天行BBB评分,7 d后取材。采用HE染色观察大鼠脊髓组织受损程度,尼氏染色观察神经元形态,透射电镜观察BSCB紧密连接超微结构,EB染色检测BSCB通透性。结果:与假手术组比较,模型组和活血通督汤组相同时点BBB评分显著降低(P<0.01),在干预第7天时,活血通督汤组大鼠BBB评分显著高于模型组(P<0.05)。HE染色结果显示:与模型组比较,活血通督汤组炎症细胞浸润有所减少,神经细胞形态结构较完整且数量增多,但仍存在脊髓空洞样病变;尼氏染色结果显示:与模型组比较,活血通督汤组神经细胞形态较好且数量增多,尼氏体数量较多,空泡样改变减少,瘀血面积较小或消失;透射电镜结果显示:与模型组比较,活血通督汤组大鼠脊髓血管内皮细胞紧密连接较完整,血管管腔连续性好。激光共聚焦定性观察显示:模型组血管周围组织EB渗出明显,弥散范围较大,且固有的血管形态被弥散渗出的EB所遮盖,混为一片,较难分辨。活血通督汤组较模型组EB渗出减少,灰质区血管形态也更清晰,甚至可见少量条管状血管形态;与模型组比较,活血通督汤组脊髓组织EB含量显著降低(P<0.01),与镜下观察结果一致。结论:活血通督汤可促进血管内皮细胞间紧密连接的修复,降低BSCB的通透性,抑制血管中的炎症因子和趋化因子进入脊髓组织,为脊髓微环境的稳态提供有效保护,有利于大鼠SCI后神经细胞的再生以及运动功能的恢复。

基于督脉枢机不利探讨脊髓损伤与血脊髓屏障

长期以来,脊髓损伤(SCI)的治疗主要以受损节段的修复与功能重建为主,但疗效差强人意。文章从督脉与脊髓的关系、SCI与督脉枢机不利、血脊髓屏障(BSCB)二者间的联系入手,探讨督脉枢机不利与SCI、BSCB的相关性,以期将中医药治疗督脉枢机不利作为提升SCI疗效的突破口。笔者发现,作为SCI的治疗关键之一的BSCB,其病变的相关细胞因子与督脉枢机不利密切相关,为未来SCI的研究方向提供了理论基础。