RhoA/Rock2/Limk1/cofilin1 pathway is involved in attenuation of neuronal dendritic spine loss by paeonol in the frontal cortex of D-galactose and aluminum­induced Alzheimer's disease­like rat model.

Alzheimer's disease (AD) has become the most prevalent neurodegenerative disorder. Given the pathogenesis of AD is unclear, there is currently no drug approved to halt or delay the progression of AD. Therefore, it is pressing to explore new targets and drugs for AD. In China, polyphenolic Chinese herbal medicine has been used for thousands of years in clinical application, and no toxic effects have been reported. In the present study, using D­galactose and aluminum­induced rat model, the effects of paeonol on AD were validated via the Morris water maze test, open field test, and elevated plus maze test. Neuronal morphology in frontal cortex was assessed using ImageJ's Sholl plugin and RESCONSTRUCT software. RhoA/Rock2/Limk1/cofilin1 signaling pathway­related molecules were determined by Western blotting. Cofilin1 and p­cofilin1 were analyzed by immunofluorescence. Results showed that pre­treatment with paeonol attenuated D­galactose and aluminum­induced behavioral dysfunction and AD­like pathological alterations in the frontal cortex. Accompanied by these changes were the alterations in the dendrite and dendritic spine densities, especially the mushroom­type and filopodia­type spines in the apical dendrites, as well as actin filaments. In addition, the activity and intracellular distribution of cofilin1 and the molecules RhoA/Rock2/Limk1 that regulate the signaling pathway for cofilin1 phosphorylation have also changed. Our data suggests that paeonol may be through reducing Aß levels to alleviate the loss of fibrillar actin and dendrites and dendritic spines via the Rho/Rock2/Limk1/cofilin1 signaling pathway in the frontal cortex, and ultimately improving AD­like behavior.

Novel derivative of Paeonol, Paeononlsilatie sodium, alleviates behavioral damage and hippocampal dendritic injury in Alzheimer's disease concurrent with cofilin1/phosphorylated-cofilin1 and RAC1/CDC42 alterations in rats.

Alzheimer's disease (AD) is a typical hippocampal amnesia and the most common senile dementia. Many studies suggest that cognitive impairments are more closely correlated with synaptic loss than the burden of amyloid deposits in AD progression. To date, there is no effective treatment for this disease. Paeonol has been widely employed in traditional Chinese medicine. This compound improves learning behavior in an animal model; however, the mechanism remains unclear. In this study, Paeononlsilatie sodium (Pa), a derivative of Paeonol, attenuated D-galactose (D-gal) and AlCl3-induced behavioral damages in rats based on evaluations of the open field test (OFT), elevated plus maze test (EPMT), and Morris water maze test (MWMT). Pa increased the dendritic complexity and the density of dendritic spines. Correlation analysis indicated that morphological changes in neuronal dendrites are closely correlated with behavioral changes. Pa treatment reduced the production of Aß, affected the phosphorylation and redistribution of cofilin1 and inhibited rod-like formation in hippocampal neurons. The induction of D-gal and AlCl3 promoted the expression of RAC1/CDC42 expression; however, the tendency of gene expression was inhibited by pretreatment with Pa. Taken together, our results suggest that Pa may represent a novel therapeutic agent for the improvement of cognitive and emotional behaviors and dendritic morphology in an AD animal model.

[Effects of Electroacupuncture Intervention Combined with Gastrodin on Expression of Proteins Related to Proliferation-differentiation of Neural Stem Cells in Hippocampal CA 1 and CA 3 Regions in Focal Cerebral Ischemia Rats].

OBJECTIVE: To observe the effect of electroacupuncture(EA) combined with medication on changes of expression of Nestin, glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE) in the hippocampal CA 1 and CA 3 regions of focal cerebral ischemia (FC1) rats, so as to analyze its mechanisms underlying neuroprotection. METHODS: Fifty male SD rats were randomly divided into normal control, model, EA, medication, and EA+ medication groups (n = 10 in each group). The FCI model was established by middle cerebral artery occlusion (MCAO) with thread embolus. EA (2 Hz, 2 V) was applied to the left "Hegu"(LI 4) and "Quchi" (LI 11) for 30 min, once daily for 14 days after MCAO. Rats of the medication group were given with intraperitoneal injection of gastrodin (10 mg/kg). The expression of Nestin, GFAP and NSE in the hippocampal CA 1 and CA 3 regions were detected by immunohistochemistry. RESULTS: Compared with the normal control group, the numbers of Nestin- and GFAP-immunoreaction (IR) positive cells in both CA 1 and CA 3 regions of the hippocampus were significantly increased in the model ciroup (P<0.05), while those of NSE-IR positive cells in both CA 1 and CA 3 regions were significantly decreased in the mdlgroup (P<0.05). After EA and medication interventions, the numbers of Nestin- and NSE-IR positive cells in the CA 1 and CA 3 regions were evidently increased and GFAP-IR positive neurons were considerably reduced in the EA, medication and EA+ medication groups (P<0.05). The effects of EA+ medication were significantly superior to those of both EA and simple medication in up-regulating the number of Nestin- and NSE-IR positive cells and down-regulating the number of GFAP positive neurons in CA 1 and CA 3-regions (P<0.05). CONCLUSION: EA and EA intervention combined with gastrodin can significantly up-regulate the number of Nestin- and NSE-IR positive cells, and down-regulate the number of GFAP positive cells in the CA 1 and CA 3 regions of hippocampus in focal cerebral ischemia rats, which may contribute to their effects in promoting the differentiation and proliferation of mature neurons in the hippocampus for improving cerebral functions. The effects of EA+ medication are obviously better than simple EA intervention.