Gastrodin ameliorates cognitive dysfunction in diabetes by inhibiting PAK2 phosphorylation.

Diabetes is associated with higher prevalence of cognitive dysfunction, while the underlying mechanism is still elusive. In this study, we aim to explore the potential mechanism of diabetes-induced cognitive dysfunction and assess the therapeutic effects of Gastrodin on cognitive dysfunction. Diabetes was induced by a single injection of streptozotocin. The Morris Water Maze Test was employed to assess the functions of spatial learning and memory. Transcriptome was used to identify the potential factors involved. Western blot and immunofluorescence were applied to detect the protein expression. Our results have shown that spatial learning was impaired in diabetic rats, coupled with damaged hippocampal pyramidal neurons. Gastrodin intervention ameliorated the spatial learning impairments and neuronal damages. Transcriptomics analysis identified differential expression genes critical for diabetes-induced hippocampal damage and Gastrodin treatment, which were further confirmed by qPCR and western blot. Moreover, p21 activated kinase 2 (PAK2) was found to be important for diabetes-induced hippocampal injury and its inhibitor could promote the survival of primary hippocampal neurons. It suggested that PAK2 pathway may be involved in cognitive dysfunction in diabetes and could be a therapeutic target for Gastrodin intervention.

Periplaneta americana Extracts Accelerate Liver Regeneration via a Complex Network of Pathways.

Successful recovery from hepatectomy is partially contingent upon the rate of residual liver regeneration. The traditional Chinese medicines known as Periplaneta americana extracts (PAEs) positively influence wound healing by promoting tissue repair. However, the effect of PAEs on liver regeneration is unknown. We used a mouse liver regeneration model after 70% partial hepatectomy (PH) and a hepatocyte culture to determine whether PAEs can promote liver regeneration as effectively as skin regeneration and establish their modes of action. L02 cells were divided into serum-starved control (NC) and three PAEs (serum starvation + 0.1 mg/ml, 0.5 mg/ml, or 1 mg/ml PAEs) groups. L02 cell proliferation was assessed at 24 h, 48 h, and 72 h by CCK-8 assay. Forty male C57 mice were randomly divided into control (NC), normal saline (NS), PAEs400 (400 mg/kg/d), and PAEs800 (800 mg/kg/d) groups (n = 10 per group). The NS and both PAEs groups were administered normal saline and PAEs, respectively, by gavage for 10 days. Two hours after the tenth gavage, the NS and both PAEs groups were subjected to 70% PH and the residual liver was harvested after 48 h. The hepatic regeneration rate was evaluated and hepatocyte proliferation was estimated by immunohistochemical (IHC) staining for Ki-67. Twelve DEG libraries (three samples per group) were prepared and sequencing was performed in an Illumina HiSeq 2000 (Mus_musculus) at the Beijing Genomics Institute. The genes expressed in the liver tissues and their expression profiles were analyzed by bioinformatics. KEGG was used to annotate, enrich, and analyze the pathways. PAEs promoted hepatocyte proliferation in vitro and in vivo and accelerated mouse liver regeneration after 70% PH. The screening criteria were fold change (FC) ≥ 2 and q-value < 0.001. We identified 1,092 known DEGs in PAEs400 and PAEs800. Of these, 153 were categorized in cellular processes. The KEGG analysis revealed that the aforementioned DEGs participated in several signaling pathways closely associated with cell proliferation including PI3K-Akt, MAPK, Apelin, Wnt, FoxO, mTOR, Ras, VEGF, ErbB, Hippo, and AMPK. It was concluded that PAEs can effectively improve liver regeneration via the synergistic activation of different signaling pathways.

Early Intervention of Gastrodin Improved Motor Learning in Diabetic Rats Through Ameliorating Vascular Dysfunction.

The mechanism of cognitive dysfunction in diabetes is still unclear. Recently, studies have shown that the cerebellum is involved in cognition. Furthermore, diabetes-induced cerebellar alterations is related to vascular changes. Therefore, we aimed to explore the roles of vascular function in diabetes-induced cerebellar damage and motor learning deficits. Type 1 diabetes was induced by a single injection of streptozotocin in Sprague-Dawley rats. Motor learning was assessed by beam walk test and beam balance test. The pathological changes of the cerebellum were assessed by Hematoxylin and eosin staining and Nissl staining. Apoptosis was evaluated by anti-caspase-3 immunostaining. Protein expression was evaluated by western blotting and double immunofluorescence. Our results have shown that motor learning was impaired in diabetic rats, coupled with damaged Purkinje cells and decreased capillary density in the cerebellum. In addition, the protein expression of neuronal NOS, inducible NOS, endothelial NOS, total nitric oxide, vascular endothelial growth factor and its cognate receptor Flk-1 was decreased in the cerebellum. Gastrodin treatment ameliorated neuronal damage and restored protein expression of relevant factors. Arising from the above, it is suggested that vascular dysfunction and NO signaling deficits in the cerebellum may be the underlying mechanism of early manifestations of cognitive impairment in diabetes, which could be ameliorated by gastrodin intervention.

Gastrodin Ameliorates Motor Learning Deficits Through Preserving Cerebellar Long-Term Depression Pathways in Diabetic Rats.

Cognitive dysfunction is a very severe consequence of diabetes, but the underlying causes are still unclear. Recently, the cerebellum was reported to play an important role in learning and memory. Since long-term depression (LTD) is a primary cellular mechanism for cerebellar motor learning, we aimed to explore the role of cerebellar LTD pathways in diabetic rats and the therapeutic effect of gastrodin. Diabetes was induced by a single injection of streptozotocin into adult Sprague-Dawley rats. Motor learning ability was assessed by a beam walk test. Pathological changes of the cerebellum were assessed by Hematoxylin-Eosin (HE) and Nissl staining. Cellular apoptosis was assessed by anti-caspase-3 immunostaining. Protein expression levels of LTD pathway-related factors, including GluR2, protein kinase C (PKC), NR2A, and nNOS, in the cerebellar cortex were evaluated by western blotting and double immunofluorescence. The NO concentration was measured. The cellular degeneration and the apoptosis of Purkinje cells were evident in the cerebellum of diabetic rats. Protein expression levels of GluR2 (NC9W: 1.26 ± 0.12; DM9W + S: 0.81 ± 0.07), PKC (NC9W: 1.66 ± 0.10; DM9W + S: 0.58 ± 0.19), NR2A (NC9W: 1.40 ± 0.05; DM9W + S: 0.63 ± 0.06), nNOS (NC9W: 1.26 ± 0.12; DM9W + S: 0.68 ± 0.04), and NO (NC9W: 135.61 ± 31.91; DM9W + S: 64.06 ± 24.01) in the cerebellum were significantly decreased in diabetic rats. Following gastrodin intervention, the outcome of motor learning ability was significantly improved (NC9W: 6.70 ± 3.31; DM9W + S: 20.47 ± 9.43; DM9W + G: 16.04 ± 7.10). In addition, degeneration and apoptosis were ameliorated, and this was coupled with the elevation of the protein expression of the abovementioned biomarkers. Arising from the above, we concluded that gastrodin may contribute to the improvement of motor learning by protecting the LTD pathways in Purkinje cells.

Rapamycin Increases Collateral Circulation in Rodent Brain after Focal Ischemia as detected by Multiple Modality Dynamic Imaging.

Rationale: Brain collaterals contribute to improving ischemic stroke outcomes. However, dynamic and timely investigations of collateral blood flow and collateral restoration in whole brains of living animals have rarely been reported. Methods: Using multiple modalities of imaging, including synchrotron radiation angiography, laser speckle imaging, and micro-CT imaging, we dynamically explored collateral circulation throughout the whole brain in the rodent middle cerebral artery occlusion model. Results: We demonstrated that compared to control animals, 4 neocollaterals gradually formed between the intra- and extra-arteries in the skull base of model animals after occlusion (p<0.05). Two main collaterals were critical to the supply of blood from the posterior to the middle cerebral artery territory in the deep brain (p<0.05). Abundant small vessel and capillary anastomoses were detected on the surface of the cortex between the posterior and middle cerebral artery and between the anterior and middle cerebral artery (p<0.05). Collateral perfusion occurred immediately (≈15 min) and was maintained for up to 14 days after occlusion. Further study revealed that administration of rapamycin at 15 min after MCAO dilated the existing collateral vessels and promoted collateral perfusion. Principal conclusions: Our results provide evidence of collateral functional perfusion in the skull base, deep brain, and surface of the cortex. Rapamycin was capable of enlarging the diameter of collaterals, potentially extending the time window for ischemic stroke therapy.

Early intervention with gastrodin reduces striatal neurotoxicity in adult rats with experimentally­induced diabetes mellitus.

Glutamate­induced excitotoxicity in the striatum has an important role in neurodegenerative diseases. It has been reported that diabetes mellitus (DM) induces excitotoxicity in striatal neurons, although the underlying mechanism remains to be fully elucidated. The present study aimed to investigate the effect of gastrodin on DM­induced excitotoxicity in the striatal neurons of diabetic rats. Adult Sprague­Dawley rats were divided into control, diabetic, and gastrodin intervention groups. Diabetes in the rats was induced with a single intraperitoneal injection of streptozotocin (65 mg/kg). In the gastrodin groups, the rats were gavaged with 60 or 120 mg/kg/day gastrodin for 6 weeks, 3 weeks following the induction of diabetes. Pathological alterations in the striatum were assessed using hematoxylin and eosin (H&E) staining. The protein expression levels of phosphorylated (p)­extracellular signal­regulated kinase (ERK)1/2, p­mitogen­activated protein kinase kinase (MEK)1/2, tyrosine receptor kinase B (TrKB) and brain­derived neurotrophic factor (BDNF) in the striatal neurons were evaluated by western blotting and double immunofluorescence. Additionally, the extracellular levels of glutamate were measured by microanalysis followed by high­pressure­liquid­chromatography. In diabetic rats, striatal neuronal degeneration was evident following H&E staining, which revealed the common occurrence of pyknotic nuclei. This was coupled with an increase in glutamate levels in the striatal tissues. The protein expression levels of p­ERK1/2, p­MEK1/2, TrKB and BDNF in the striatal tissues were significantly increased in the diabetic rats compared with those in the normal rats. In the gastrodin groups, degeneration of the striatal neurons was ameliorated. Furthermore, the expression levels of glutamate, p­ERK1/2, p­MEK1/2, TrKB and BDNF in the striatal neurons were decreased. From these findings, it was concluded that reduced neurotoxicity in striatal neurons following treatment with gastrodin may be attributed to its suppressive effects on the expression of p­ERK1/2, p­MEK1/2, BDNF and TrKB.

Expression Changes of NMDA and AMPA Receptor Subunits in the Hippocampus in rats with Diabetes Induced by Streptozotocin Coupled with Memory Impairment.

Cognitive impairment in diabetes (CID) is a severe chronic complication of diabetes mellitus (DM). It has been hypothesized that diabetes can lead to cognitive dysfunction due to expression changes of excitatory neurotransmission mediated by N-methyl-D-aspartate receptors (NMDAR) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR); however, the pathogenesis involved in this has not been fully understood, especially at early phase of DM. Here, we sought to determine the cognitive changes and aim to correlate this with the expression changes of NMDAR and AMPAR of glutamate signaling pathways in the rat hippocampus from early phase of DM and in the course of the disease progression. By Western blot analysis and immunofluorescence labeling, the hippocampus in diabetic rats showed a significant increase in protein expression NMDAR subunits NR1, NR2A and NR2B and AMPAR subunit GluR1. Along with this, behavioral test by Morris water maze showed a significant decline in their performance when compared with the control rats. It is suggested that NR1, NR2A, NR2B and GluR1are involved in learning and memory and that their expression alterations maybe correlated with the occurrence and development of CID in diabetic rats induced by streptozotocin.

Dynamic Detection of Thrombolysis in Embolic Stroke Rats by Synchrotron Radiation Angiography.

A rodent model of embolic middle cerebral artery occlusion is used to mimic cerebral embolism in clinical patients. Thrombolytic therapy is the effective treatment for this ischemic injury. However, it is difficult to detect thrombolysis dynamically in living animals. Synchrotron radiation angiography may provide a novel approach to directly monitor the thrombolytic process and assess collateral circulation after embolic stroke. Thirty-six adult Sprague-Dawley rats underwent the embolic stroke model procedure and were then treated with tissue plasminogen activator. The angiographic images were obtained in vivo by synchrotron radiation angiography. Synchrotron radiation angiography confirmed the successful establishment of occlusion and detected the thrombolysis process after the thrombolytic treatment. The time of thrombolytic recanalization was unstable during embolic stroke. The infarct volume increased as the recanalization time was delayed from 2 to 6 h (p < 0.05). The collateral circulation of the internal carotid artery to the ophthalmic artery, the olfactory artery to the ophthalmic artery, and the posterior cerebral artery to the middle cerebral artery opened after embolic stroke and manifested different opening rates (59%, 24%, and 75%, respectively) in the rats. The opening of the collateral circulation from the posterior cerebral artery to the middle cerebral artery alleviated infarction in rats with successful thrombolysis (p < 0.05). The cerebral vessels of the circle of Willis narrowed after thrombolysis (p < 0.05). Synchrotron radiation angiography provided a unique tool to dynamically detect and assess the thrombolysis process and the collateral circulation during thrombolytic therapy.

Intravitreal Bevacizumab Injection Attenuates Diabetic Retinopathy in Adult Rats with Experimentally Induced Diabetes in the Early Stage.

Diabetic retinopathy is the leading cause of blindness, yet its treatment is very limited. Anti-VEGF drug has been widely applied in ocular disease, but its effects on diabetic retinopathy and the underlying mechanism have remained to be fully explored. To elucidate the role of anti-VEGF treatment, we sought to determine the effects of bevacizumab on diabetic neurovascular changes extending from the 3rd to 9th week with induced diabetes in adult rats. The retinal neurovascular changes included increased expression of VEGF, nNOS, iNOS, eNOS, and NO in the course of diabetes progression. In diabetic rats given bevacizumab injection, the ganglion cell loss and alterations of retinal thickness were ameliorated. In this connection, the immunofluorescence labeling of the above biomarkers was noticeably decreased. Along with this, Western blotting confirmed that bevacizumab treatment was associated with a decrease of VEGF, Flk-1, and cAMP response element binding and protein kinase C protein expression. The present results suggest that bevacizumab treatment in the early stage of the retinopathy may ameliorate the lesions of retinopathy, in which VEGF/Flk-1 signaling has been shown here to play an important role.

Simultaneous Imaging of Cerebrovascular Structure and Function in Hypertensive Rats Using Synchrotron Radiation Angiography.

Hypertension has a profound influence on the structure and function of blood vessels. Cerebral vessels undergo both structural and functional changes in hypertensive animals. However, dynamic changes of cerebrovasculature and the factors involved in this process are largely unknown. In this study, we explored the dynamic changes of vascular structure in hypertensive rats using novel synchrotron radiation angiography. Twenty-four spontaneously hypertensive rats (SHR) and 24 Sprague-Dawley (SD) rats underwent synchrotron radiation (SR) angiography. Each group had 8 animals. We studied the cerebral vascular changes in SHR over a time period of 3-12-month and performed quantitative analysis. No vascular morphology differences between SHR and SD rats were observed in the early stage of hypertension. The number of twisted blood vessels in the front brain significantly increased at the 9- and 12-month observation time-points in the SHR compared to the SD rats (p < 0.01). The vessel density of the cortex and the striatum in SHR was consistently higher than that in SD rats at time points of 3-, 9-, and 12-month (p < 0.001). Vascular elasticity decreased both in SHR and SD rats with aging. There were statistically significant differences in the relative vascular elasticity of extracranial/intracranial internal carotid artery, middle cerebral artery, posterior cerebral artery and anterior cerebral artery between SHR and SD rats at 12-month (p < 0.01). We concluded that the dynamic vascular alterations detected by SR angiography provided novel imaging data for the study of hypertension in vivo. The longer the course of hypertension was, the more obvious the vascular differences between the SHR and the SD rats became.

Hypoxia Response Element-Regulated MMP-9 Promotes Neurological Recovery via Glial Scar Degradation and Angiogenesis in Delayed Stroke.

Matrix metalloproteinase 9 (MMP-9) plays a beneficial role in the delayed phase of middle cerebral artery occlusion (MCAO). However, the mechanism is obscure. Here, we constructed hypoxia response element (HRE)-regulated MMP-9 to explore its effect on glial scars and neurogenesis in delayed ischemic stroke. Adult male Institute of Cancer Research (ICR) mice underwent MCAO and received a stereotactic injection of lentivirus carrying HRE-MMP-9 or normal saline (NS)/lentivirus-GFP 7 days after ischemia. We found that HRE-MMP-9 improved neurological outcomes, reduced ischemia-induced brain atrophy, and degraded glial scars (p < 0.05). Furthermore, HRE-MMP-9 increased the number of microvessels in the peri-infarct area (p < 0.001), which may have been due to the accumulation of endogenous endothelial progenitor cells (EPCs) in the peri-infarct area after glial scar degradation. Finally, HRE-MMP-9 increased the number of bromodeoxyuridine-positive (BrdU+)/NeuN+ cells and the expression of PSD-95 in the peri-infarct area (p < 0.01). These changes could be blocked by vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor SU5416 and MMP-9 inhibitor 2-[[(4-phenoxyphenyl)sulfonyl]methyl]-thiirane (SB-3CT). Our results provided a novel mechanism by which glial scar degradation and vascular endothelial growth factor (VEGF)/VEGFR2-dependent angiogenesis may be key procedures for neurological recovery in delayed ischemic stroke after HRE-MMP-9 treatment. Therefore, HRE-MMP-9 overexpression in the delayed ischemic brain is a promising approach for neurological recovery.

Vessel Dilation Attenuates Endothelial Dysfunction Following Middle Cerebral Artery Occlusion in Hyperglycemic Rats.

OBJECTIVES: Dynamically observe cerebral vascular changes in hyperglycemic rats in vivo and explore the effect of diabetes on endothelial function after ischemic stroke. BACKGROUND: Diabetes affects both large and small vessels in the brain, but the dynamic process and mechanism are unclear. METHODS: We investigated the structural and functional changes of brain vasculature in living hyperglycemic rats and their impact on stroke outcomes via a novel technique: synchrotron radiation angiography. We also examined the effect of prolonged fasudil treatment on arterial reactivity and hemorrhagic transformation. Adult Sprague Dawley rats were treated by streptozotocin to induce type 1 diabetes. These hyperglycemic rats received fasudil pretreatment and then underwent transient middle cerebral artery occlusion. RESULTS: We found that diabetes caused arteries narrowing in the circus Willis as early as 2 weeks after streptozotocin injection (P < 0.05). These vessels were further constricted after middle cerebral artery occlusion. L-NAME could induce regional constrictions and impaired relaxation in hyperglycemic animals. Furthermore, hemorrhagic transformation was also increased in the hyperglycemic rats compared to the control (P < 0.05). In fasudil-treated rats, the internal carotid artery narrowing was ameliorated and L-NAME-induced regional constriction was abolished. Importantly, stroke prognosis was improved in fasudil-treated rats compared to the control (P < 0.05). CONCLUSIONS: Our dynamic angiographic data demonstrated that diabetes could impair the cerebral arterial reactivity. Prolonged fasudil treatment could attenuate arterial dysfunction and improve the prognosis of ischemic stroke by affecting both the large and small vasculature.

Early Use of Statin in Patients Treated with Alteplase for Acute Ischemic Stroke.

Studies have reported that statin usage before stroke can increase the incidence of intracerebral hemorrhage after thrombolytic treatment. However, whether the administration of statin at an early stage of ischemic stroke increases hemorrhage occurrence is unknown. The aim of this study was to assess the effect of statin on neurological imaging and functional outcomes after intravenous alteplase treatment, within 24 h of acute ischemic stroke attack. A total of 119 consecutive acute ischemic stroke patients treated by intravenous alteplase were recruited, of which 71 patients (59.7 %) were given statin therapy within 24 h of stroke onset. The physiological parameters, including demography, vascular risk factors, and clinical characteristics were recorded. The occurrence of intracerebral hemorrhage (ICH), symptomatic intracerebral hemorrhage (sICH), 90-day functional outcomes, and mortality in the patients were further analyzed. There were 24 occurrences of ICH after alteplase treatment (20.2 %) and there was no difference when patients were treated with statin (p = 0.280). Multivariate logistic regression analysis showed no significant correlation between the administration of statin and the occurrence of ICH (p = 0.230) or sICH (p = 0.949). There was a trend toward better neurological function with higher statin dose. The use of statin in the early stage of ischemic stroke is safe and does not increase the risk of intracerebral hemorrhage after alteplase treatment, suggesting that a clinical trial of early statin treatment on a large scale following thrombolysis is needed for further evaluation.

Hypoxia-controlled matrix metalloproteinase-9 hyperexpression promotes behavioral recovery after ischemia.

Matrix metalloproteinase-9 (MMP-9) plays a beneficial role in the sub-acute phase after ischemic stroke. However, unrestrained MMP-9 may disrupt the blood-brain barrier (BBB), which has limited its use for the treatment of brain ischemia. In the present study, we constructed lentivirus mediated hypoxia-controlled MMP-9 expression and explored its role after stroke. Hypoxia response element (HRE) was used to confine MMP-9 expression only to the hypoxic region of mouse brain after 120-min transient middle cerebral artery occlusion. Lentiviruses were injected into the peri-infarct area on day 7 after transient ischemia. We found hyperexpression of exogenous HRE-MMP-9 under the control of hypoxia, and its expression was mainly located in neurons and astrocytes without aggravation of BBB damage compared to the CMV group. Furthermore, mice in the HRE-MMP-9 group showed the best behavioral recovery compared with the normal saline, GFP, and SB-3CT groups. Therefore, hypoxia-controlled MMP-9 hyperexpression during the sub-acute phase of ischemia may provide a novel promising approach of gene therapy for stroke.

Development of functional in vivo imaging of cerebral lenticulostriate artery using novel synchrotron radiation angiography.

The lenticulostriate artery plays a vital role in the onset and development of cerebral ischemia. However, current imaging techniques cannot assess the in vivo functioning of small arteries such as the lenticulostriate artery in the brain of rats. Here, we report a novel method to achieve a high resolution multi-functional imaging of the cerebrovascular system using synchrotron radiation angiography, which is based on spatio-temporal analysis of contrast density in the arterial cross section. This method provides a unique tool for studying the sub-cortical vascular elasticity after cerebral ischemia in rats. Using this technique, we demonstrated that the vascular elasticity of the lenticulostriate artery decreased from day 1 to day 7 after transient middle cerebral artery occlusion in rats and recovered from day 7 to day 28 compared to the controls (p < 0.001), which paralleled with brain edema formation and inversely correlated with blood flow velocity (p < 0.05). Our results demonstrated that the change of vascular elasticity was related to the levels of brain edema and the velocity of focal blood flow, suggesting that reducing brain edema is important for the improvement of the function of the lenticulostriate artery in the ischemic brain.

Collateral circulation prevents masticatory muscle impairment in rat middle cerebral artery occlusion model.

The rat suture middle cerebral artery occlusion (MCAO) is a frequently used animal model for investigating the mechanisms of ischemic brain injury. During suture MCAO, transection of the external carotid artery (ECA) potentially restrains blood flow and impairs masticatory muscle and other ECA-supported territories, consequently influencing post-operation animal survival. This study was aimed at investigating the effect of ECA transection on the hemodynamic alterations using a novel synchrotron radiation (SR) angiography technique and magnetic resonance imaging in live animals. Fifteen male adult Sprague-Dawley rats were used in this study. Animals underwent MCAO, in which the ECA was transected. SR angiography was performed before and after MCAO. Rats then underwent magnetic resonance imaging (MRI) to detect the tissue lesion both intra- and extra-cranially. Animals with SR angiography without other manipulations were used as control. High-resolution cerebrovascular morphology was analyzed using a novel technique of SR angiography. The masticatory muscle lesion was further examined by hematoxylin and eosin staining. MRI and histological results showed that there was no masticatory muscle lesion at 1, 7 and 28 days following MCAO with ECA transection. In normal condition, the ECA and its branch external maxillary artery were clearly detected. Following ECA transection, the external maxillary artery was still observed and the blood supply appeared from the anastomotic branch from the pterygopalatine artery. SR angiography further revealed the inter-relationship of hemisphere extra- and intra-cranial vasculature in the rat following MCAO. Transection of the ECA did not impair masticatory muscles in rat suture MCAO. Interrupted blood flow could be compensated by the collateral circulation from the pterygopalatine artery.

Effect of HMGB1 on the paracrine action of EPC promotes post-ischemic neovascularization in mice.

Transplantation of endothelial progenitor cells (EPCs) leads to better outcomes in experimental stroke, but the mechanism remains unclear. It was reported that astrocytic-high mobility group box1 (HMGB1) promoted endogenous EPC-mediated neurovascular remodeling during stroke recovery. It is unclear whether HMGB1 involves in exogenous EPC-mediated stroke recovery. In this study, we aim to explore whether microglial HMGB1 contributes to human peripheral blood-derived (hPB)-EPCs-mediated neurovascular remodeling by modulating the paracrine function of exogenous hPB-EPCs. Coculturing hPB-EPCs with lipopolysaccharides stimulated BV2 cells upregulated Interleukin-8 expression in hPB-EPCs; this was blocked by treating BV2 cells with HMGB1 inhibitor Glycyrrhizin. Conditioned medium (CM) of hPB-EPCs cocultured with BV2 cells promoted the viability and tube formation of human umbilical cord vein cells. Inhibiting either HMGB1 or IL-8 could block the effect of hPB-EPCs CM. In vivo study showed hPB-EPCs transplantation improved neurobehavioral outcomes, reduced brain atrophy volume, and enhanced neovascularization in transient middle cerebral artery occlusion (tMCAO) mice. Intraperitoneally administration of HMGB1 inhibitor glycyrrhizin blocked the beneficial effect of hPB-EPC transplantation. We did not observe the integration of green fluorescent protein-labeled hPB-EPCs with microvessels in peri-infarct areas at day-14 after tMCAO. In summary, the result suggested that HMGB1 upregulation in postischemic brain could promote exogenous hPB-EPC-mediated stroke recovery by modulating paracrine function of hPB-EPCs.