Quercetin attenuates the reduction of parvalbumin in middle cerebral artery occlusion animal model / 한국실험동물학회지

Background@#Calcium is a critical factor involved in modulation of essential cellular functions. Parvalbumin is a calcium buffering protein that regulates intracellular calcium concentrations. It prevents rises in calcium concentrations and inhibits apoptotic processes during ischemic injury. Quercetin exerts potent antioxidant and anti-apoptotic effects during brain ischemia. We investigated whether quercetin can regulate parvalbumin expression in cerebral ischemia and glutamate toxicity-induced neuronal cell death. Adult male rats were treated with vehicle or quercetin (10 mg/kg) 30 min prior to middle cerebral artery occlusion (MCAO) and cerebral cortical tissues were collected 24 h after MCAO. We used various techniques including Western blot, reverse transcriptionPCR, and immunohistochemical staining to elucidate the changes of parvalbumin expression. @*Results@#Quercetin ameliorated MCAO-induced neurological deficits and behavioral changes. Moreover, quercetin prevented MCAO-induced a decrease in parvalbumin expression. @*Conclusions@#These findings suggest that quercetin exerts a neuroprotective effect through regulation of parvalbumin expression.

Quercetin attenuates the reduction of parvalbumin in middle cerebral artery occlusion animal model / 한국실험동물학회지

Background@#Calcium is a critical factor involved in modulation of essential cellular functions. Parvalbumin is a calcium buffering protein that regulates intracellular calcium concentrations. It prevents rises in calcium concentrations and inhibits apoptotic processes during ischemic injury. Quercetin exerts potent antioxidant and anti-apoptotic effects during brain ischemia. We investigated whether quercetin can regulate parvalbumin expression in cerebral ischemia and glutamate toxicity-induced neuronal cell death. Adult male rats were treated with vehicle or quercetin (10 mg/kg) 30 min prior to middle cerebral artery occlusion (MCAO) and cerebral cortical tissues were collected 24 h after MCAO. We used various techniques including Western blot, reverse transcriptionPCR, and immunohistochemical staining to elucidate the changes of parvalbumin expression. @*Results@#Quercetin ameliorated MCAO-induced neurological deficits and behavioral changes. Moreover, quercetin prevented MCAO-induced a decrease in parvalbumin expression. @*Conclusions@#These findings suggest that quercetin exerts a neuroprotective effect through regulation of parvalbumin expression.

Resveratrol modulates the Akt/GSK-3β signaling pathway in a middle cerebral artery occlusion animal model / 한국실험동물학회지

Cerebral ischemia is a major cause of neurodegenerative disease. It induces neuronal vulnerability and susceptibility, and leads to neuronal cell death. Resveratrol is a polyphenolic compound that acts as an anti-oxidant. It exerts a neuroprotective effect against focal cerebral ischemic injury. Akt signaling pathway is accepted as a representative cell survival pathway, including proliferation, growth, and glycogen synthesis. This study investigated whether resveratrol regulates Akt/glycogen synthase kinase-3β (GSK-3β) pathway in a middle cerebral artery occlusion (MCAO)-induced ischemic brain injury. Adult male rats were intraperitoneally injected with vehicle or resveratrol (30 mg/kg) and cerebral cortices were isolated 24 h after MCAO. Neurological behavior test, corner test, brain edema measurment, and 2,3,5-triphenyltetrazolium chloride staining were performed to elucidate the neuroprotective effects of resveratrol. Phospho-Akt and phospho-GSK-3β expression levels were measured using Western blot analysis. MCAO injury led to severe neurobehavioral deficit, infraction, and histopathological changes in cerebral cortex. However, resveratrol treatment alleviated these changes caused by MCAO injury. Moreover, MCAO injury induced decreases in phospho-Akt and phospho-GSK-3β protein levels, whereas resveratrol attenuated these decreases. Phosphorylations of Akt and GSK-3β act as a critical role for the suppression of apoptotic cell death. Thus, our finding suggests that resveratrol attenuates neuronal cell death in MCAO-induced cerebral ischemia and Akt/GSK-3β signaling pathway contributes to the neuroprotective effect of resveratrol.

Quercetin attenuates the injury-induced reduction of γ-enolase expression in a middle cerebral artery occlusion animal model / 한국실험동물학회지

Quercetin, a natural flavonoid, copiously exists in vegetable, fruits and tea. Quercetin is beneficial to neurodegenerative disorders via its strong anti-oxidant and anti-inflammatory activities. γ-Enolase is one of the enzymes of glycolytic pathway and is predominantly expressed in neuronal cells. The aim of the present study is to verify whether quercetin modulates the expression of γ-enolase in brain ischemic injury. Adult Sprague-Dawley male rats were subjected to middle cerebral artery occlusion (MCAO) and quercetin (50 mg/kg) or vehicle was administered by intraperitoneal injection at 1 h before MCAO onset. A proteomics study, Western blot analysis, reversetranscription-PCR, and immunofluorescence staining were conducted to investigate the change of γ-enolase expression level. We identified a decline in γ-enolase expression in MCAO-operated animal model using a proteomic approach. However, quercetin treatment significantly attenuated this decline. These results were confirmed using Western blot analysis, reverse transcription-PCR, and immunofluorescence staining techniques. γ-Enolase is accepted as a neuron specific energy synthesis enzyme, and quercetin modulates γ-enolase in a MCAO animal model. Thus, our findings can suggest the possibility that quercetin regulates γ-enolase expression in response to cerebral ischemia, which likely contributes to the neuroprotective effect of quercetin.

Curcumin attenuates the middle cerebral artery occlusion-induced reduction in gamma-enolase expression in an animal model / 한국실험동물학회지

Curcumin exerts a protective effect in cerebral ischemia through its anti-oxidant and anti-inflammatory activities. gamma-enolase is a glycolytic enzyme expressed in neurons that is known to exerts a neuroprotective effect. We investigated whether curcumin regulates gamma-enolase expression in focal cerebral ischemic injury in rats. Middle cerebral artery occlusion (MCAO) was performed to induce focal cerebral ischemia. Adult male rats were injected intraperitoneally with either vehicle or curcumin (50 mg/kg) 1 h after MCAO and cerebral cortex tissues were isolated 24 h after MCAO. We found that MCAO-induced injury resulted in a reduction in gamma-enolase expression in vehicle-treated animals using a proteomics approach. However, this reduction was attenuated in animals with MCAO treated with curcumin. Reverse-transcription PCR and Western blot analyses also showed that curcumin treatment prevented the MCAO injury-induced reduction in gamma-enolase expression. The results of this study suggest that curcumin exerts its neuroprotective function in focal cerebral ischemia by regulating the expression of gamma-enolase.

Curcumin treatment recovery the decrease of protein phosphatase 2A subunit B induced by focal cerebral ischemia in Sprague-Dawley rats / 한국실험동물학회지

Curcumin provides various biological effects through its anti-inflammatory and antioxidant properties. Moreover, curcumin exerts a neuroprotective effect against ischemic condition-induced brain damage. Protein phosphatase 2A (PP2A) is a ubiquitous serine and threonine phosphatase with various cell functions and broad substrate specificity. Especially PP2A subunit B plays an important role in nervous system. This study investigated whether curcumin regulates PP2A subunit B expression in focal cerebral ischemia. Cerebral ischemia was induced surgically by middle cerebral artery occlusion (MCAO). Adult male rats were injected with either vehicle or curcumin (50 mg/kg) 1 h after MCAO and cerebral cortex tissues were isolated 24 h after MCAO. A proteomics study, reverse transverse-PCR and Western blot analyses were performed to examine PP2A subunit B expression levels. We identified a reduction in PP2A subunit B expression in MCAO-operated animals using a proteomic approach. However, curcumin treatment prevented injury-induced reductions in PP2A subunit B levels. Reverse transverse-PCR and Western blot analyses confirmed that curcumin treatment attenuated the injury-induced reduction in PP2A subunit B levels. These findings can suggest that the possibility that curcumin maintains levels of PP2A subunit B in response to cerebral ischemia, which likely contributes to the neuroprotective function of curcumin in cerebral ischemic injury.

Ferulic acid regulates the AKT/GSK-3beta/CRMP-2 signaling pathway in a middle cerebral artery occlusion animal model / 한국실험동물학회지

Ferulic acid, a component of the plants Angelica sinensis (Oliv.) Diels and Ligusticum chuanxiong Hort, exerts a neuroprotective effect by regulating various signaling pathways. This study showed that ferulic acid treatment prevents the injury-induced increase of collapsin response mediator protein 2 (CRMP-2) in focal cerebral ischemia. Glycogen synthase kinase-3beta (GSK-3beta) regulates CRMP-2 function through phosphorylation of CRMP-2. Moreover, the pro-apoptotic activity of GSK-3beta is inactivated by phosphorylation by Akt. This study investigated whether ferulic acid modulates the expression of CRMP-2 and its upstream targets, Akt and GSK-3beta, in focal cerebral ischemia. Male rats were treated immediately with ferulic acid (100 mg/kg, i.v.) or vehicle after middle cerebral artery occlusion (MCAO), and then cerebral cortices were collected 24 hr after MCAO. MCAO resulted in decreased levels of phospho-Akt and phospho-GSK-3beta, while ferulic acid treatment prevented the decrease in the levels of these proteins. Moreover, phospho-CRMP-2 and CRMP-2 levels increased during MCAO, whereas ferulic acid attenuated these injury-induced increases. These results demonstrate that ferulic acid regulates the Akt/GSK-3beta/CRMP-2 signaling pathway in focal cerebral ischemic injury, thereby protecting against brain injury.

Ginkgo biloba extract (EGb 761) prevents the ischemic brain injury-induced decrease in parvalbumin expression / 한국실험동물학회지

Ginkgo biloba extract (EGb 761) exerts a neuroprotective effect against ischemic brain injury through an anti-apoptotic mechanism. Parvalbumin is a calcium buffering protein that plays an important role in modulating intracellular calcium concentration and regulating apoptotic cell death. The aim of this study was to investigate whether EGb 761 affects parvalbumin expression in cerebral ischemic injury. Adult male Sprague-Dawley rats were treated with vehicle or EGb 761 (100 mg/kg) prior to middle cerebral artery occlusion (MCAO) and cerebral cortex tissues were collected 24 h after MCAO. A proteomic approach revealed a reduction in parvalbumin expression in the vehicle-treated animals, whereas EGb 761 pretreatment attenuates the ischemic injury-induced decrease in parvalbumin expression. RT-PCR and Western blot analyses clearly confirmed the fact that EGb 761 prevents the injury-induced decrease in parvalbumin. Moreover, the results of immunohistochemical staining showed that the number of parvalbumin-positive cells was lower in vehicle-treated animals than in sham-operated animals, and EGb 761 averted this decrease. Thus, these results suggest that the maintenance of parvalbumin expression is associated with the neuroprotective function of EGb 761 against neuronal damage induced by ischemia.