Osthole, a natural coumarin improves cognitive impairments and BBB dysfunction after transient global brain ischemia in C57 BL/6J mice: involvement of Nrf2 pathway.

Oxidative stress and blood-brain barrier (BBB) disruption play important roles in cerebral ischemic pathogenesis and may represent targets for treatment. Earlier studies have shown that osthole, a main active constituent isolated from Cnidium monnieri (L.) Cusson, could be considered as an attractive therapeutic agent in the treatment of ischemic stroke. However, the mechanism underlying the protective effect remains vague. In this study we aimed to investigate the effect of osthole on transient cerebral ischemia as well as its mechanism(s) in C57 BL/6 J mice. Mice were subjected to transient global cerebral ischemia induced by bilateral common carotid artery occlusion for 25 min. Behavioral test was performed at 4 days after ischemia, followed by assessment of neuronal loss in hippocampal CA1 region. Osthole significantly improved the cognitive ability and enhanced the survival of pyramidal neurons in the CA1 region of mice after lesion. Further studies showed that osthole attenuated the permeation of BBB, which may contribute to antioxidative effect by increasing the superoxide dismutase activity and decreasing the malondialdehyde level in model mice. Further studies revealed that osthole obviously up-regulated the protein levels of nuclear factor erythroid 2-related factor 2/heme oxygenase 1 in HT22 cells. In conclusion, our findings indicated that osthole exerts neuroprotective effects against global cerebral ischemia injury by reducing oxidative stress injury and reserving the disruption of BBB, which may be attributed to elevating the protein levels of Nrf2 and HO-1.

The effects of chronic copper exposure on the amyloid protein metabolisim associated genes' expression in chronic cerebral hypoperfused rats.

The pathogens of Alzheimer's disease (AD) are still unclear, while accumulating evidences have indicated that both genetic and environmental factors are involved in the pathogenesis of AD. Recent studies suggest that AD is primarily a vascular disorder and copper (Cu) may play an important role in AD pathology. However, the consequences of chronic Cu exposure at the presence of other AD risk factors remain to be clarified. To investigate the effects of chronic Cu intake on cerebral hypoperfusion-induced AD pathology, Sprague-Dawley rats suffered bilateral common carotid artery occlusion (2VO) were administrated with 250 ppm copper-containing water or not. Morris water maze test showed that Cu exposure for 3 months exacerbated cognitive impairment induced by 2VO. Elevated amyloid precursor protein (APP) and beta-site APP-cleaving enzyme 1 (BACE1) expression in mRNA and protein levels were also observed in brain of Cu-exposed rats suffered 2VO. In contrast, these Cu-exacerbated changes were ameliorated after Cu was withdrawn from drinking water. In summary, our findings demonstrate that chronic Cu exposure might exacerbate AD pathology in 2VO rats.

Tacrine-6-ferulic acid, a novel multifunctional dimer, inhibits amyloid-ß-mediated Alzheimer's disease-associated pathogenesis in vitro and in vivo.

We have previously synthesized a series of hybrid compounds by linking ferulic acid to tacrine as multifunctional agents based on the hypotheses that Alzheimer's disease (AD) generates cholinergic deficiency and oxidative stress. Interestingly, we found that they may have potential pharmacological activities for treating AD. Here we report for the first time that tacrine-6-ferulic acid (T6FA), one of these compounds, can prevent amyloid-ß peptide (Aß)-induced AD-associated pathological changes in vitro and in vivo. Our results showed that T6FA significantly inhibited auto- and acetylcholinesterase (AChE)-induced aggregation of Aß(1-40)in vitro and blocked the cell death induced by Aß(1-40) in PC12 cells. In an AD mouse model by the intracerebroventricular injection of Aß(1-40), T6FA significantly improved the cognitive ability along with increasing choline acetyltransferase and superoxide dismutase activity, decreasing AChE activity and malondialdehyde level. Based on our findings, we conclude that T6FA may be a promising multifunctional drug candidate for AD.

Osthole, a natural coumarin, improves neurobehavioral functions and reduces infarct volume and matrix metalloproteinase-9 activity after transient focal cerebral ischemia in rats.

Previously we demonstrated that Osthole, a natural coumarin, protects against focal cerebral ischemia/reperfusion-induced injury in rats. In the present study, the effects of Osthole on neurobehavioral functions, infarct volume and matrix metalloproteinase-9 (MMP-9) in a rat 2h focal cerebral ischemia model were investigated. Osthole (100mg/kg per dose) was administrated intraperitoneally 30min before ischemic insult and immediately after reperfusion. Osthole treatment significantly reduced neurological deficit score and infarct volume by 38.5% and 33.8%, respectively, as compared with the untreated animals. Osthole reversed ischemia-reperfusion-induced increase in MMP-9 protein level/activity as evidenced by Western blotting and gelatin zymography. Taken together, these results for the first time demonstrate that Osthole reduces infarct volume, restores neurobehavioral functions and downregulates MMP-9 protein level/activity in ischemia/reperfused brain.

The orally combined neuroprotective effects of sodium ferulate and borneol against transient global ischaemia in C57 BL/6J mice.

OBJECTIVES: This study aimed to investigate the possible modification of the neuroprotective effect of sodium ferulate, when orally co-administered with borneol, in transient global cerebral ischaemia-induced functional, histological and cellular alterations in mice. METHODS: The bilateral common carotid artery occlusion was conducted in C57 BL/6J mice for 25 min. The mice were then subjected to a water maze test over an extended recovery period, followed by an assessment of neuronal loss in the CA1 region of the hippocampus (haematoxylin and eosin staining). The blood-brain barrier permeability (Evans blue tracing), brain oedema and oxidative stress were assayed and histological sections were also immunostained for gliofibrillar acid protein (GFAP) expression. KEY FINDINGS: The ischaemia reperfused mice were associated with long-lasting spatial learning deficits in the absence of other behavioural impairments and with neurodegeneration in the hippocampal CA1 region. However, the histological injuries were significantly attenuated by oral co-administration of sodium ferulate and borneol. Furthermore, combined treatment with sodium ferulate and borneol resulted in a significant reduction in brain oedema, GFAP-positive cells, malonaldialdehyde levels and blood-brain barrier permeability, but an increase in superoxide dismutase activity. CONCLUSIONS: Borneol may have benefits for the neuroprotective effect of sodium ferulate against injury induced in the brain by ischaemia/reperfusion.

Combination of methylprednisolone and minocycline synergistically improves experimental autoimmune encephalomyelitis in C57 BL/6 mice.

Combination therapies with existing or novel drugs for multiple sclerosis (MS) have great clinical potential to improve MS treatment outcomes. Our previous studies had confirmed that the combined treatment of minocycline and prednisone produced beneficial effects partially through preventing the reduction of brain-derived neurotrophic factor and nerve growth factor mRNA expression in the cerebral cortex of experimental autoimmune encephalomyelitis (EAE) mice. As high-dose methylprednisolone administered intravenously has more superior efficacy than oral prednisone and had been provided as a stable therapy for MS patients at the onset of an acute relapse, we further evaluated the effects of combined methylprednisolone and minocycline at suboptimal doses on EAE mice at the acute stage in this study. Interferon gamma (IFN-γ) and interleukin-4 (IL-4), the hallmark cytokines that direct Th1 and Th2 development and play an important role in the pathogenesis of MS as well as EAE, were also assayed. Obtained results showed that combined treatment could successfully attenuate severe clinical deficit and suppress histopathological events in EAE. In addition, reduced IFN-γ and increased IL-4 production/expression were found in the splenocytes culture supernatants and brains of EAE mice by the combined treatment. Our data indicate that the combination of methylprednisolone and minocycline may be a promising therapy for MS.

Attenuation of experimental autoimmune encephalomyelitis in C57 BL/6 mice by osthole, a natural coumarin.

Osthole, a natural coumarin, is known to have a variety of pharmacological and biochemical uses and is considered to have potential therapeutic applications. Here we examined the effects of osthole on the central nervous system demyelination in experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis and its mechanism(s). C57 BL/6 mice immunized with myelin oligodendrocyte glycoprotein 35-55 amino acid peptide were treated with osthole at day 7 post immunization (7 p.i., subclinical periods, early osthole treatment) and day 13 p.i. (clinical periods, late osthole treatment) respectively and both therapies continued throughout the study. The content of nerve growth factor (NGF) and interferon gamma (IFN-gamma) in the sera and brain of mice in vivo as well as the splenocytes culture supernatants in vitro were detected. The results showed that osthole retarded the disease process when the therapy was initiated at subclinical periods, attenuated the clinical severity of EAE mice when the therapy was initiated at both subclinical and clinical periods, ameliorated inflammation and demyelination and improved the outcomes of magnetic resonance imaging. In addition, osthole blocked the reduction of NGF and suppressed IFN-gamma increase in EAE mice. These results suggested that osthole might be a new pharmacological approach to treat multiple sclerosis.

Alterations in mRNA expression of BACE1, cathepsin B, and glutaminyl cyclase in mice ischemic brain.

The relationship between cerebral ischemia and Alzheimer's disease has been evaluated extensively. However, the association between cerebral ischemia and the deposition of beta-amyloid (Abeta) remains to be clarified. Here, we used mice bilateral common carotid artery ligation model to investigate the alterations in mRNA expression of Abeta precursor protein cleavage enzyme 1(BACE1), cathepsin B, and glutaminyl cyclase after transient global cerebral ischemia. The reverse-transcriptase PCR assay showed that the expressions of these three Abeta-metabolism-related genes were upregulated in brain with different manner. It indicates that all these three Abeta-metabolism-related genes may participate in the acute and chronic Abeta generation after transient cerebral ischemia, and will be helpful to understand the mechanisms underlying the linkage of brain ischemia and Alzheimer's disease.