Linyu Chen

Bicyclol upregulates transcription factor Nrf2, HO-1 expression and protects rat brains against focal ischemia.

UNLABELLED Oxidative damage plays a detrimental role in the pathophysiology of cerebral ischemia and may represent a therapeutic target. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) controls the coordinated expression of the important antioxidant and detoxification genes through a promotor sequence termed the antioxidant response element. Bicyclol has been proved to elicit a variety of biological effects through its antioxidant and anti-inflammatory properties. But the underlying mechanisms are poorly understood. In this study, the role of bicyclol in cerebral ischemia and its potential mechanism were investigated. METHODS Male Sprague-Dawley rats were randomly assigned to five groups: MCAO (middle cerebral artery occlusion), Vehicle (MCAO+0.5% sodium carboxymethylcellulose), By-L (Vehicle+bicyclol 50mg/kg), By-H (Vehicle+bicyclol 100mg/kg) and Sham operated groups. Bicyclol was administered intragastrically once a day for 3 consecutive days; after 1h of bicyclol pretreatment on the third day, rat ischemic stroke was induced by MCAO. Neurological deficit, infarct volume, and brain edema were detected at 24h after stroke. Western blot and RT-qPCR were used to measure the expression of Nrf2, HO-1 and SOD1. MDA was detected by the spectrophotometer. RESULTS Compared with MCAO group, By-H group significantly ameliorated neurological deficit, lessened the infarct volume and brain edema, increased the expression of Nrf2, HO-1 and SOD1 (P<0.05), and decreased the content of MDA (P<0.05). CONCLUSIONS Bicyclol protected the rat brain from ischemic damage caused by MCAO, and this effect may be through the upregulation of the transcription factor Nrf2 expression.

Nobiletin protects against cerebral ischemia via activating the p-Akt, p-CREB, BDNF and Bcl-2 pathway and ameliorating BBB permeability in rat

There is cumulative evidence that the serine-threonine kinase Akt and its downstream nuclear transcription factor CREB are involved in neuronal survival and protection. The Akt activates and phosphorylates CREB at Ser133, resulting in the up-regulation of pro-survival CREB target genes such as BDNF and Bcl-2. Thus, Akt/CREB signaling pathway may be one propitious target for treatment of ischemic cerebral injury. Nobiletin (NOB) exhibits a wide spectrum of beneficial biological properties including anti-inflammatory, antioxidant, anti-carcinogenic actions and contributes to reverse learning impairment in Alzheimers disease rat. However, little is currently known regarding the exact role of NOB in ischemic stroke. Here, we designed to evaluate its possible therapeutic effect on cerebral ischemia. Adult male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (pMCAO) and randomly divided into five groups: Sham (sham-operated+0.05% Tween-80), MCAO (pMCAO+0.9% saline), Vehicle group (pMCAO+0.05% Tween-80), NOB-L (pMCAO+NOB 10 mg/kg) and NOB-H (pMCAO+NOB 25 mg/kg) groups. Rats were pre-administered intraperitoneally once daily for 3 days before surgery and then received once again immediately after surgery. Neurological deficit scores, brain water content and infarct volume were evaluated at 24 h after stroke. Additionally, the activities of Akt, CREB, BDNF, Bcl-2 and claudin-5 in ischemic brain cortex were analyzed by the methods of immunohistochemistry, western blot and RT-qPCR. Compared with Vehicle group, neurological deficits and brain edema were relieved in NOB-H group (P<0.05), infarct volume was lessened in both NOB-L and NOB-H groups (P<0.05) at 24 h after stroke. Immunohistochemistry, western blot and RT-qPCR analysis indicated that NOB dramatically promoted the activities of Akt, CREB, BDNF and Bcl-2 (P<0.05). Meanwhile, claudin-5 expression was also enhanced. On the basis of these findings, we concluded that NOB protected the brain from ischemic damage and it maybe through activating the Akt/CREB signaling pathway and ameliorating BBB permeability.

The protection by Octreotide against experimental ischemic stroke: Up-regulated transcription factor Nrf2, HO-1 and down-regulated NF-κB expression

BACKGROUND Inflammatory and oxidative damage play a pivotal role in cerebral ischemic pathogenesis and may represent a therapeutic target. Octreotide (OCT) has been proved to elicit a variety of biological effects through its anti-inflammatory and anti-oxidant properties in the treatment of severe acute pancreatitis and ischemia-reperfusion injury in retina and intestine. However little is known regarding the effect of OCT in ischemic stroke. Here, we designed this study to investigate the protective effect of OCT in ischemic stroke and explore the potential underlying mechanisms. METHODS Male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (pMCAO) and randomly divided into four groups: Sham (sham-operated), MCAO (pMCAO+0.9% saline), OCT-L (pMCAO+OCT 50μg/kg) and OCT-H (pMCAO+OCT 100μg/kg) groups. OCT was administered intraperitoneally immediately after stroke. Neurological deficit scores, infarct volume and brain water content were measured at 24h after stroke. Immunohistochemical staining and western blot were used to analyze the expressions of Nrf2, HO-1 and NF-κB. SOD and MDA were measured by spectrophotometer. RESULTS Compared with MCAO group, OCT significantly alleviated neurological deficit, lessened infarct volume and brain edema (P<0.05), upregulated the expression of Nrf2, HO-1 and SOD (P<0.05), and decreased the expression of NF-κB and MDA (P<0.05). CONCLUSIONS OCT protected the brain against cerebral ischemic damage; this effect may be through upregulation of transcription factor Nrf2, HO-1 and downregulation of NF-κB expression.

Protection by silibinin against experimental ischemic stroke: Up-regulated pAkt, pmTOR, HIF-1α and Bcl-2, down-regulated Bax, NF-κB expression

Inflammation and apoptosis play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Silibinin has been proved to elicit a variety of biological effects through its anti-inflammatory and anti-apoptotic properties in hepatotoxic, cancer and carcinogenic events. Whether this protective effect applies to ischemic injury in brain is still unknown, we therefore investigated the potential protective role of silibinin in ischemic stroke and the underlying mechanisms. Silibinin was administered intragastric 30 min before permanent middle cerebral artery occlusion (pMCAO). We found that silibinin significantly alleviated neurological deficit, reduced infarct volume, and suppressed brain edema, which were accompanied with upregulation of pAkt, pmTOR, HIF-1α, Bcl-2 and downregulation of Bax, NF-κB in ischemic brain tissue after stroke. Our results show that silibinin might exert anti-inflammatory and anti-apoptotic effects in ischemic brain through activating Akt/mTOR signaling.

Paeonol pretreatment attenuates cerebral ischemic injury via upregulating expression of pAkt, Nrf2, HO-1 and ameliorating BBB permeability in mice

BACKGROUND Oxidative damage plays a pivotal role in the pathogenesis of cerebral ischemic stroke and may represent a target for treatment. Our previous studies have proved that nuclear factor E2-related factor 2 (Nrf2) and its downstream genes served as a key mechanism for protection against oxidative stress. Paeonol (PN) is reputed to possess a broad range of therapeutic properties probably by virtue of its antioxidative ability. However little is elucidated regarding the underlying mechanisms in ischemic stroke. The aim of this study was to explore PNs effect in ischemic injury and the role of the pAkt, Nrf2 and hemeoxygenase-1 (HO-1) in the mice brains of permanent middle cerebral artery occlusion (pMCAO). METHODS Male CD-1 mice were subjected to pMCAO and randomly divided into five groups: Sham (sham-operated+0.9% saline), pMCAO (pMCAO+0.9% saline), Vehicle (pMCAO+vehicle), PN-L (pMCAO+PN 30 mg/kg) and PN-H (pMCAO+PN 60 mg/kg) groups. PN was pre-administered intragastrically once daily for 3 days and with the last administration at 30 min before the operation in the fourth day. Neurological deficit scores, brain water content and infarct volume were measured at 24h after pMCAO. Western blot and qRT-PCR were employed to determine the expressions of pAkt, Nrf2, HO-1 and claudin-5. Superoxide dismutase (SOD) and malondialdehyde (MDA) were measured by spectrophotometer. RESULTS Compared with Vehicle group, PN significantly alleviated neurological deficit, infarct volume and brain edema (P<0.05), upregulated the expression of pAkt, Nrf2, HO-1 and SOD (P<0.05), decreased the level of MDA (P<0.05). Meanwhile, the expression of claudin-5 was also enhanced. CONCLUSIONS PN reduced ischemic brain injury after pMCAO; this effect may be accompanied with upregulation of pAkt, Nrf2, HO-1 and ameliorating BBB permeability.

Neuroprotective effect of bicyclol in rat ischemic stroke: down-regulates TLR4, TLR9, TRAF6, NF-κB, MMP-9 and up-regulates claudin-5 expression.

BACKGROUND Inflammatory damage aggravates the cerebral ischemic pathological process and may pave a new way for treatment. Bicyclol has been proved to elicit a series of biologic effects through its anti-inflammatory property in treating hepatitis and hepatic ischemic/reperfusion injury. Whether this protective effect applies to cerebral ischemic injury, we therefore investigated the potential neuroprotective role of bicyclol and the underlying mechanisms. METHODS Male Sprague-Dawley rats were randomly assigned to five groups: permanent middle cerebral artery occlusion (pMCAO), Vehicle (pMCAO+0.5% sodium carboxymethylcellulose), By-L (Vehicle+bicyclol 50 mg/kg), By-H (Vehicle+bicyclol 100 mg/kg) and Sham operated group. Bicyclol was administered intragastrically once a day for 3 days, after 1h of bicyclol pretreatment on the third day; rat brain ischemia was induced by pMCAO. Neurological deficit, infarct volume, and brain edema were measured at 24 h after stroke. Immunohistochemistry, Western blot and real-time quantitative PCR were used to detect the expression of TLR4, TLR9, TRAF6, NF-κB and MMP-9, claudin-5. RESULTS Compared with pMCAO group, bicyclol significantly ameliorated neurological deficit, decreased infarct volume and edema, and down-regulated the expression of TLR4, TLR9, TRAF6, NF-κB and MMP-9 (P<0.05). Meanwhile, the expression of claudin-5 was increased (P<0.05). CONCLUSIONS Bicyclol has neuroprotective effect on cerebral ischemia, and this protection may be through down-regulating TLR4, TLR9, TRAF6, NF-κB, MMP-9 and up-regulating claudin-5 expression.

Neuroprotective effect of early and short-time applying sophoridine in pMCAO rat brain: down-regulated TRAF6 and up-regulated p-ERK1/2 expression, ameliorated brain infaction and edema.

BACKGROUND Matrine has been proven to protect ischemic injury in brain and sophoridine (SOP) is an isomeride of matrine. It is unknown whether SOP has this protective effect on ischemic injury in brain. We therefore investigated the potential neuroprotective role of SOP and the underlying mechanism. METHODS Male, Sprague-Dawley rats were randomly assigned into five groups: Vehicle (pMCAO+saline), High dose (pMCAO+SOP 10 mg/kg), Middle dose (pMCAO+SOP 5 mg/kg), Low dose (pMCAO+SOP 2.5 mg/kg) and Sham operated group. Permanent middle cerebral artery occlusion (pMCAO) model was used and SOP was administered intraperitoneally immediately after cerebral ischemia and once daily in the following days. Neurological deficit was evaluated using a modified six point scale; brain water content and infarct volume were measured. The expression of TRAF6 and ERK1/2 were measured by immunohistochemistry, Western blotting. RESULTS Compared with Vehicle group, the cerebral edema was alleviated in High dose group (P<0.05), and the infarct volume was decreased in Low dose group (P<0.05). Consistent with these results, immunohistochemistry and Western blot analysis indicated that TRAF6 expression was significantly decreased in SOP administrated groups at 24 h, and the expression of phosphorylated ERK1/2 increased in Low dose at 72 h. CONCLUSIONS SOP protected the brain from damage caused by pMCAO, and this effect may be through down-regulation of TRAF6 expression and up-regulation of ERK1/2 phosphorylation expression.

Nobiletin promotes antioxidant and anti-inflammatory responses and elicits protection against ischemic stroke in vivo

BACKGROUND Post-ischemic oxidative stress and inflammation play pivotal roles in the pathogenesis of ischemic stroke and may represent therapeutic targets. Nobiletin (NOB) has been reported to elicit a variety of biological effects through its anti-oxidant and anti-inflammatory properties. Our previous study has demonstrated the beneficial effect of NOB in ischemic stroke, but the underlying mechanisms remain poorly defined. We therefore further investigated the role of NOB in cerebral ischemia and its potential mechanisms. METHODS Adult male Sprague-Dawley rats were randomly assigned to five groups: Sham (sham-operated+0.05% Tween-80), permanent middle cerebral artery occlusion (pMCAO+0.9% saline), Vehicle (pMCAO+0.05% Tween-80), NOB-L (pMCAO+NOB 10mg/kg) and NOB-H (pMCAO+NOB 25mg/kg) groups. Rats were pre-administered intraperitoneally once daily for 3 days prior to ischemia and then received once again immediately after surgery. Neurological deficit, brain edema and infarct volume were evaluated at 24h after stroke. Immunohistochemistry, western blot and RT-qPCR were used to detect the expression of Nrf2, HO-1, SOD1, NF-κB and MMP-9. SOD1, GSH and MDA were measured by spectrophotometer. RESULTS Compared with Vehicle group, neurological deficits and brain edema were relieved in NOB-H group, infarct volume was lessened in both NOB-L and NOB-H groups (P<0.05). NOB significantly increased the expression of Nrf2, HO-1, SOD1 and GSH, while decreased the levels of NF-κB, MMP-9 and MDA (P<0.05). CONCLUSION NOB may have a neuroprotective effect on cerebral ischemia, and this protection may be through upregulating Nrf2, HO-1 and downregulating NF-κB expression.

MiR-503 suppresses hypoxia-induced proliferation, migration and angiogenesis of endothelial progenitor cells by targeting Apelin

HighlightsMiR‐503 suppresses hypoxia‐induced proliferation, migration and angiogenesis of endothelial progenitor cells.MiR‐503 directly targets to Apelin via its 3′‐UTR region in EPCs.Increased expression of Apelin promotes EPC growth, migration and angiogenesis under hypoxia. ABSTRACT Endothelial progenitor cells (EPCs) are of great importance in the process of endogenous blood vessel repair to maintain endothelial integrity and have been applied in a wide range of models of ischemic diseases. MicroRNAs represent a class of non‐protein coding endogenous RNAs with 19–24 nucleotides in length and serve an important role in multiple physiological and pathological processes, including angiogenesis. It has been reported that miR‐503 reduces angiogenesis in tumorigenesis. However, to our knowledge, the precise role of miR‐503 in the regulation of EPCs remains unclear. In the current study, we found that the expression of miR‐503 was decreased in mouse bone marrow derived EPCs under the hypoxic condition. Importantly, upregulation of miR‐503 suppressed the proliferation, migration and capillary‐like tube formation of EPCs induced by hypoxia. Furthermore, a dual luciferase reporter assay showed that Apelin, an endogenous ligand of the G protein‐coupled receptor APJ, was a direct target of miR‐503 and overexpression of miR‐503 significantly inhibited the protein level of Apelin in EPCs. Moreover, hypoxia treatment enhanced the expression of Apelin in EPCs. Meanwhile ectopic expression of Apelin promoted cellular proliferation, migration and tube formation of EPCs in vitro. In summary, our results indicate that miR‐503 regulates proliferation, migration and angiogenesis of EPCs by targeting Apelin.