Xiangjian Zhang

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

BACKGROUND Oxidative and cytotoxic damage plays an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Curcumin is proved to elicit a vanity of biological effects through its antioxidant and anti-inflammatory properties. But the mechanisms underlying are poorly understood. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) coordinates expression of genes required for free radical scavenging, detoxification of xenobiotics, and maintenance of redox potential. This study evaluated the time course expression regularity of Nrf2, HO-1 and the curcumins role in cerebral ischemia and its potential mechanism. METHODS Male, Sprague-Dawley rats were subjected to permanent focal cerebral ischemia by right MCA occlusion. Experiment 1 was used to evaluate the expression of Nrf2 and HO-1 in the cerebral ischemia, 6 time points was included. Experiment 2 was used to detect curcumins neuroprotection in cerebral ischemia. At 24 h neurological deficit was evaluated using a modified six point scale; brain water content was measured; infarct size was analysed with 2, 3, 5-triphenyltetrazolium chloride (TTC). Immunohistochemistry, RT-PCR, Western blot, and confocal microscope were used to analyse the expression of Nrf2 and HO-1. RESULTS Compared with sham-operated, Nrf2 and HO-1 were upregulated at gene and protein level in ischemic brain, beginning at 3 h and peaking at 24 h after MCAO (P<0.05). Curcumin high dose (100 mg/kg) upregulated Nrf2 and HO-1 in MCAO-affected brain tissue and reduced infarct volume (P<0.05), brain water content (P<0.05) and behavioral deficits (P<0.05) caused by MCAO. CONCLUSIONS Nrf2 and HO-1 were induced at the early stage after MCAO. Curcumin protected the brain from damage caused by MCAO, this effect may be through upregulation of the transcription factor Nrf2 expression. Nrf2 may be one of the strategic targets for cerebral ischemic therapies.

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.

Tanshinone II A down-regulates HMGB1, RAGE, TLR4, NF-κB expression, ameliorates BBB permeability and endothelial cell function, and protects rat brains against focal ischemia

Inflammatory damage plays an important role in cerebral ischemic pathogenesis. HMGB1-induced NF-kappaB activation pathway has been gaining recognition as a key contributor to the proinflammatory response. Tanshinone II A (Tan II A) has been proved to elicit a series of biologic effects through its antiinflammatory property. But the mechanism underlying is poorly understood. This study evaluated the Tan II As protective role in cerebral ischemia and its potential mechanism. Male Sprague-Dawley rats were subjected to pMCAO. Experiment 1 was used to evaluate the longitudinal expression of HMGB1, RAGE and TLR4 and NF-kappaB in the cerebral ischemia. Experiment 2 was used to detect Tan II As neuroprotection. At 24 h after pMCAO, neurologic deficit, brain water content and infarct size were measured. Immunohistochemistry, RT-PCR, Western blot and confocal microscope were used to analyze the expression of HMGB1, RAGE, TLR4 and NF-kappaB. Experiment 3 was used to detect Tan II As influence on BBB. The expressions of HMGB1, TLR4, RAGE and NF-kappaB were up-regulated in ischemic brain. Compared with pMCAO group, the expressions of these factors significantly decreased in Tan II A-H group, the neurologic deficit, infarct volume and brain water content were alleviated (P<0.05) and claudin-5 was predominantly expressed in brain capillaries. Tan II A protected the brain from damage caused by pMCAO; this effect may be through down-regulation of HMGB1, RAGE and TLR4, NF-kappaB and up-regulation claudin-5 expression.

Oxymatrine protects rat brains against permanent focal ischemia and downregulates NF-κB expression

BACKGROUND Oxymatrine is proven to protect ischemic and reperfusion injury in liver, intestine and heart, this effect is via anti-inflammation and anti-apoptosis. Whether this protective effect applies to ischemic injury in brain, we therefore investigate the potential neuroprotective role of oxymatrine and the underlying mechanisms. METHODS Male, Sprague-Dawley rats were randomly assigned to four groups: permanent middle cerebral artery occlusion (pMCAO), high dose (pMCAO+oxymatrine 120 mg/kg), low dose (pMCAO+oxymatrine 60 mg/kg) and sham operated group. We used a permanent middle cerebral artery occlusion model and administered oxymatrine intraperitoneally immediately after cerebral ischemia and once daily on the following days. At 24 h after MCAO, neurological deficit was evaluated using a modified six point scale; brain water content was measured; NF-kappaB expression was measured by immunohistochemistry, Western blotting and RT-PCR. Infarct volume was analyzed with 2, 3, 5-triphenyltetrazolium chloride (TTC) staining at 72 h. RESULTS Compared with pMCAO group, neurological deficit in high dose group was improved (P<0.05), infarct volume was decreased (P<0.001) and cerebral edema was alleviated (P<0.05). Consistent with these indices, immunohistochemistry, Western blot and RT-PCR analysis indicated that NF-kappaB expression was significantly decreased in high dose group. Low dose of oxymatrine did not affect NF-kappaB expression in pMCAO rats. CONCLUSIONS Oxymatrine reduced infarct volume induced by pMCAO, this effect may be through the decreasing of NF-kappaB expression.

Baicalein is neuroprotective in rat MCAO model: Role of 12/15-lipoxygenase, mitogen-activated protein kinase and cytosolic phospholipase A2

Inflammatory damage and oxidative stress play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Baicalein, isolated from the traditional Chinese herbal medicine Huangqin, is an antioxidant and anti-inflammatory agent on one hand and a lipoxygenase inhibitor on the other hand. However, little is known regarding the mechanism of baicaleins neuroprotection in ischemic stroke. We therefore investigated the potential neuroprotective effects of baicalein and explored the underlying mechanisms. Male, Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (MCAO) and baicalein was administered intravenously immediately after cerebral ischemia. At 24h after MCAO neurological deficit, brain water content and infarct sizes were measured. Immunohistochemistry, western blot and reverse transcription-polymerase chain reaction (RT-PCR) were used to analyse the expression of 12/15-lipoxygenase (12/15-LOX), p38 mitogen-activated protein kinase (p38 MAPK) and cytosolic phospholipase A2 (cPLA2) at gene and protein levels in ischemic brain cortex. The results showed that baicalein improved neurological deficit, reduced brain water content and infarct sizes, and downregulated the overexpression of 12/15-LOX, p38 MAPK and cPLA2 typically seen with MCAO. The results indicated that baicalein protected the brain from damage caused by MCAO, and this effect may be through downregulation of 12/15-LOX, p38 MAPK and cPLA2 expression.

Luteolin downregulates TLR4, TLR5, NF-κB and p-p38MAPK expression, upregulates the p-ERK expression, and protects rat brains against focal ischemia

BACKGROUND Inflammatory damage is known to be involved in ischemic stroke. Luteolin has been proved to elicit a series of biologic effects through its anti-inflammatory property in multiple sclerosis and rheumatoid arthritis. Whether this protective effect applies to ischemic injury in brain is still unknown, we therefore investigate the potential neuroprotective role of luteolin in ischemic stroke and the underlying mechanisms. METHODS Male Sprague-Dawley rats were subjected to pMCAO and luteolin was administered intraperitoneally immediately after surgery, then once daily thereafter. Neurological deficit, infarct volume, and brain water content were measured at 24 h and 72 h after stroke. The expression of TLR4, TLR5, and NF-κB were measured by real-time PCR, immunohistochemical staining (IHC), and Western blot. P38MAPK and extracellular signal-regulated kinase (ERK) were detected by IHC, and Western blot. RESULTS Compared with pMCAO group, luteolin significantly alleviated neurological deficit, decreased infarct volume and suppressed edema after ischemic stroke, which were accompanied with decreased expression of TLR4, TLR5, NF-κB and p-p38MAPK. Meanwhile, luteolin activated the expression of p-ERK1/2 (P<0.05). CONCLUSIONS Luteolin protected the brain from the damage caused by pMCAO, and this effect may be through downregulation of TLR4, TLR5, NF-κB, p38MAPK and upregulation of ERK expression.

Polydatin modulates inflammation by decreasing NF-κB activation and oxidative stress by increasing Gli1, Ptch1, SOD1 expression and ameliorates blood-brain barrier permeability for its neuroprotective effect in pMCAO rat brain.

Inflammation and oxidative stress play an important role in cerebral ischemic pathogenesis. Polydatin has been proved to elicit numerous biological effects through its anti-inflammatory and anti-oxidant properties. However, little is known regard to the mechanism of polydatins neuroprotection in ischemic stroke. We therefore investigated the potential neuroprotective effects of polydatin and explored the underlying mechanisms. Male, Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (pMCAO). Experiment 1 was used to evaluate the expression of glioma-associated oncogene homolog1 (Gli1), Patched-1 (Ptch1) and Superoxide dismutase 1 (SOD1) after pMCAO, six time points were included. Experiment 2 was used to detect polydatins neuroprotection after pMCAO. Neurological deficit, brain water content and infarct size were measured at 24h and 72 h after pMCAO. Immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR), Western Blotting, activity assay and confocal microscope were used to analyse the expression of Gli1, Ptch1, SOD1 and nuclear factor-kappa B (NF-κB). Experiment 3 was used to detect polydatins influence on blood-brain barrier (BBB). Compared with Sham group, the expression of Gli1, Ptch1 and SOD1 were up-regulated shortly after pMCAO (P<0.05). Compared with Vehicle group, high dose of polydatin (50mg/kg) up-regulated Gli1, Ptch1, SOD1 and down-regulated NF-κB, and reduced infarct volume, brain water content and behavioral deficits (P<0.05). Meanwhile, BBB permeability was also ameliorated. The results indicated that polydatin protected the brain from damage caused by pMCAO, and this effect may be through up-regulating the expression of Gli1, Ptch1 and SOD1 and down-regulating the expression of NF-κB, and ameliorating BBB permeability.

Oxymatrine downregulates TLR4, TLR2, MyD88, and NF-kappaB and protects rat brains against focal ischemia.

Inflammatory damage plays an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Toll-like receptor-4 (TLR4), toll-like receptor-2 (TLR2), myeloid differentiation factor 88 (MyD88), and nuclear factor kappa-B (NF-κB) have been linked to inflammatory reactions. Our previous studies have proved that oxymatrine (OMT) protected ischemic brain injury and this effect may be through the decreasing of NF-κB expression. However, little is known regarding the mechanism of OMT in the acute phase of ischemic stroke. We therefore investigated the OMTs potential neuroprotective role and the underlying mechanisms. Male, Sprague-Dawley rats were randomly divided into sham, saline and OMT treatment groups. We used a middle cerebral artery occlusion (MCAO) model and administered OMT intraperitoneally immediately after cerebral ischemia and once daily on the following days. At time points after MCAO, brain water content and infarct size were measured. Immunohistochemistry and RT-PCR were used to analyse the expression of TLR4, TLR2, MyD88, and NF-κB at gene and protein level in ischemic brain tissue. The result indicated that OMT protected the brain from damage caused by MCAO; this effect may be through downregulation of the TLR4, TLR2, MyD88, and NF-κB.

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.

Neuroprotection of early and short-time applying berberine in the acute phase of cerebral ischemia: up-regulated pAkt, pGSK and pCREB, down-regulated NF-κB expression, ameliorated BBB permeability.

BACKGROUND Berberine (BBR) has gained attention for its vast beneficial biological effects through immunomodulation, anti-inflammatory and anti-apoptosis properties. Inflammatory and apoptosis damage play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The aim of this study was to explore BBRs effect in ischemic injury and the role of the Akt/GSK (glycogen synthase kinase) signaling cascade in mediating the anti-apoptosis and anti-inflammatory effects in the rat brain of permanent middle cerebral artery occlusion (pMCAO). Male Sprague-Dawley rats were subjected to pMCAO and randomly assigned into four groups: Sham (sham-operated) group, pMCAO (pMCAO+0.9% saline) group, BBR-L (pMCAO+BBR 10 mg/kg) and BBR-H (pMCAO+BBR 40 mg/kg) group. BBR was administered immediately after pMCAO and the neuroprotection was detected. Phospho-Akt (pAkt), phospho-glycogen synthase kinase 3-β (pGSK3β), phospho-cAMP response element binding protein (pCREB), nuclear factor-kappa B (NF-κB) and claudin-5 in ischemic cerebral cortex were detected by immunohistochemistry, reverse transcription-polymerase chain reaction and western blotting. Compared with pMCAO group, BBR dramatically lessened neurological deficits scores, brain water contents and infarct sizes, upregulated the expression of pAkt, pGSK3β, pCREB and claudin-5, and decreased the nuclear accumulation of NF-κB (P<0.05) in ischemic brain. The results showed that BBR reduced ischemic brain injury after pMACO, and this effect may be via the increasing the activation of Akt/GSK signaling and claudin-5, and decreasing NF-κB expression.