Protective activity of the ethanol extract of Cynanchum paniculatum (BUNGE) Kitagawa on treating herpes simplex encephalitis.

To date there has been no valid treatment for herpes simplex encephalitis (HSV). This study explores the protective activity of ethanol extract of Cynanchum paniculatum (bunge) kitagawa for treatment of HSV. Cell models and animal models were established and divided into 4 groups: normal group, virus group, cynanchum paniculatum group and Dexamethasone group. Flow cytometry was employed to detect apoptosis of cell model and TUNEL assay was chosen to detect apoptosis of animal tissues. The survival time of the animal models was observed. ELISA was used to measure TNF-alpha expression and the Greiss method to measure Nitric Oxide (NO) expression in the mouse brain. As a result, it was found that extract of Cynanchum paniculatum can improve the survival rate of HSV-infected mice. The extract could prevent apoptosis in the neuron cell model and reduce apoptosis rate in brain tissue after HSV infection. With the extract intervention, TNF-alpha and NO levels in brain tissue were significantly decreased in the animal model. In conclusion, the extract of Cynanchum paniculatum can prevent HSV-inducing impairment in the cell and animal model of HSE.

Exendin-4 improved rat cortical neuron survival under oxygen/glucose deprivation through PKA pathway.

Previous studies demonstrated that exendin-4 (Ex-4) may possess neurotrophic and neuroprotective functions in ischemia insults, but its mechanism remained unknown. Here, by using real-time PCR and ELISA, we identified the distribution of active GLP-1Rs in the rat primary cortical neurons. After establishment of an in vitro ischemia model by oxygen/glucose deprivation (OGD), neurons were treated with various dosages of Ex-4. The MTT assay showed that the relative survival rate increased with the dosage of Ex-4 ranging from 0.2 to 0.8 µg/ml (P<0.001, vs. OGD group). The apoptosis rate was reduced from (49.47±2.70)% to (14.61±0.81)% after Ex-4 treatment (0.4 µg/ml) 12h after OGD (P<0.001). Moreover, immunofluorescence staining indicated that Ex-4 increased glucose-regulated proteins 78 (GRP78) and reduced C/EBP-homologous protein (CHOP). Western blot analysis demonstrated that, after neurons were treated with Ex-4, GRP78 was up-regulated over time (P<0.01, vs. OGD group), while CHOP levels rose to a peak 8h after OGD and then decreased (P<0.05, vs. OGD group). This effect was changed by both the protein kinase A (PKA) inhibitor H89 (P<0.01, P<0.05, respectively, vs. Ex-4 group) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (P<0.01, P<0.01, respectively, vs. Ex-4 group) but not by the mitogen-activated protein kinase (MAPK) inhibitor U0126. Our study also revealed that, compared with the Ex-4 group, inhibition of the PKA signaling pathway significantly decreased the survival rate of neurons, down-regulated the expression of B-cell lymphoma 2 (Bcl-2) and up-regulated the Bax expression 3h after ODG (P<0.05, P<0.01, respectively), while neither PI3K nor MAPK inhibition exerted such effects. Furthermore, Western blotting exhibited that PKA expression was elevated in the presence or absence of OGD insults (P<0.05). This study indicated that Ex-4 protected neurons against OGD by modulating the unfolded protein response (UPR) through the PKA pathway and may serve as a novel therapeutic agent for stroke.

The protective effect of sonic hedgehog is mediated by the phosphoinositide [corrected] 3-kinase/AKT/Bcl-2 pathway in cultured rat astrocytes under oxidative stress.

In our previous study, we found that the sonic hedgehog (Shh) signaling pathway is activated in neurons under oxidative stress and plays a neuro-protective role [Dai RL, et al. (2011) Neurochem Res 36:67-75]; we are led to postulate that the Shh might be released by astrocytes, thereby protecting neurons against oxidant injury. In primary cultured astrocytes of rats, we found that treatment with 100 µM H2O2 for 24 h induced a significant increase in the mRNA and protein levels of Shh, Patched1, and Gli-1, and the increase was substantially greater in astrocytes than in neurons. In the coculture systems of astrocytes and neurons under the H2O2 treatment, blocking the Shh signaling pathway with 5E1 (an antibody against the N-terminal domain of Shh) could block the neuroprotective activity of astrocytes on cocultured neurons. In this study, we found that treatment with H2O2 (100-800 µM) for 24 h caused cell death of astrocytes in a concentration-dependent manner. MTT reduction and Trypan Blue exclusion assay showed that exogenous Shh increased survival rate of the H2O2-treated astrocytes, whereas pretreatment with cyclopamine (a specific inhibitor of the Shh signaling pathway) or 5E1 decreased the survival rate of the H2O2-treated astrocytes. Shh also inhibited H2O2-induced apoptosis of astrocytes, and this effect could be partially reversed by cyclopamine. We also found that Shh promoted the phosphorylation of AKT, but had no significant effect on p38 or extracellular signal regulated kinases 1 and 2 (ERK 1/2) in H2O2-treated astrocytes. Blocking Shh or phosphoinositide 3-kinases (PI3-K)/AKT signaling pathway with cyclopamine or LY294002 decreased the survival rate of astrocytes, induced cell apoptosis, upregulated the expression of Bax, and downregulated the expression of Bcl-2. We are led to conclude that the oxidative stress induces astrocytes to secrete endogenous Shh and exogenous administration of Shh might protect the astrocytes from oxidative stress by activating PI3-K/AKT/Bcl-2 pathway.