peoniflorin and Nerve-Degeneration

Paeoniflorin from Chinese herb Paeoniae Radix has been shown to ameliorate middle cerebral artery occlusion-induced ischemia in rats. The aim of this study was to investigate the mechanisms underlying the neuroprotective action of PF in cultured rat cortical neurons.. Primary cultured cortical neurons of rats were subjected to oxygen-glucose deprivation and reoxygenation (OGD/R) insult. Cell survival was determined using MTT assay. HEK293 cells stably transfected with A1R (HEK293/A1R) were used for detailed analysis. Phosphorylation of the signaling proteins was evaluated by Western blot or immunoprecipitation. Receptor interactions were identified using co-immunoprecipitation and immunofluorescence staining.. Paeoniflorin (10 nmol/L to 1 μmol/L) increased the survival of neurons subjected to OGD/R. Furthermore, paeoniflorin increased the phosphorylation of Akt and ERK1/2 in these neurons. These effects were blocked by PI3K inhibitor wortmannin or MEK inhibitor U0126. Paeoniflorin also increased the phosphorylation of Akt and ERK1/2 in HEK293/A1R cells. Both A1R antagonist DPCPX and EGFR inhibitor AG1478 not only blocked paeoniflorin-induced phosphorylation of ERK1/2 and Akt in HEK293/A1R cells, but also paeoniflorin-increased survival of neurons subjected to OGD/R. In addition, paeoniflorin increased the phosphorylation of Src kinase and activation of MMP-2 in HEK293/A1R cells. Both Src inhibitor PP2 and MMP-2/MMP-9 inhibitor BiPs not only blocked paeoniflorin-induced phosphorylation of ERK1/2 (and Akt) in HEK293/A1R cells, but also paeoniflorin-increased survival of neurons subjected to OGD/R.. Paeoniflorin promotes the survival of cultured cortical neurons by increasing Akt and ERK1/2 phosphorylation via A1R-mediated transactivation of EGFR.

Topics: Animals; Brain Ischemia; Cell Hypoxia; Cell Survival; Cerebral Cortex; Cytoprotection; Dose-Response Relationship, Drug; Enzyme Activation; ErbB Receptors; Gestational Age; Glucosides; HEK293 Cells; Humans; Matrix Metalloproteinase 2; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Monoterpenes; Nerve Degeneration; Neurons; Neuroprotective Agents; Phosphorylation; Primary Cell Culture; Proto-Oncogene Proteins c-akt; Rats, Sprague-Dawley; Receptor Cross-Talk; Receptor, Adenosine A1; Signal Transduction; src-Family Kinases; Time Factors; Transfection

Chronic cerebral hypoperfusion, a mild ischemic condition, is associated with the cognitive deficits of AD. Paeoniflorin (PF), a major constituent of peony root, was proved to be neuroprotective in middle cerebral artery occlusion model. In this study, we investigated whether PF could attenuate chronic cerebral hypoperfusion-induced learning dysfunction and brain damage in rat. Seven weeks after permanent bilateral occlusion of the common carotid arteries, the rats were tested in the Morris water maze. Subsequently, the animals were sacrificed and neurons, astrocytes and microglias were labeled with immunocytochemistry in hippocampus. PF at the dose of 2.5 mg/kg ameliorated cerebral hypoperfusion-related learning dysfunction and prevented CA1 neuron damage. Chronic cerebral hypoperfusion increased the immunoreactivity of astrocytes and microglias in hippocampus. The increase was prevented by PF at the dose of 2.5 mg/kg. Cerebral hypoperfusion also increased expression of nuclear factor-kappaB (NF-kappaB), mostly in astrocytes, but not in neurons. With the treatment of PF (2.5 mg/kg), NF-kappaB immunostaining was diminished in hippocampus. Our results demonstrated that PF could attenuate cognitive deficit and brain damage induced by chronic cerebral hypoperfusion and that suppression of neuroinflammatory reaction in brain might be involved in PF-induced neuroprotection.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzoates; Biomarkers; Brain Damage, Chronic; Brain Ischemia; Bridged-Ring Compounds; Cerebral Infarction; Disease Models, Animal; Dose-Response Relationship, Drug; Encephalitis; Gliosis; Glucosides; Hippocampus; Infarction, Middle Cerebral Artery; Learning Disabilities; Male; Maze Learning; Memory Disorders; Monoterpenes; Nerve Degeneration; Neuroglia; Neurons; Neuroprotective Agents; NF-kappa B; Rats; Treatment Outcome