Anti-Inflammatory and Neuroprotective Effects of Triptolide via the NF-κB Signaling Pathway in a Rat MCAO Model.

Stroke is the leading cause of neurological disability in humans. Middle cerebral artery occlusion (MCAO) followed by reperfusion is widely accepted to mimic stroke in basic medical research. Triptolide is one of the major active components of the traditional Chinese herb Tripterygium wilfordii Hook F, and has been reported to have potent anti-inflammatory and immunosuppressive properties. Since its preclinical effects on stroke were still unclear, we decided to study the effects of Triptolide on focal cerebral ischemia/reperfusion injury in this study. The results showed that Triptolide treatment significantly attenuates brain infarction volume, water content, neurological deficits, and neuronal cell death rate, which were increased in the MCAO model rats. Immunohistochemistry was used to analyze the expression of glial fibrillary acidic protein (GFAP), Cyclooxygenase-2 (COX-2), inducible nitric oxide (iNOS), and NF-κB in the ischemic brains. The administration of Triptolide showed down-regulation of the iNOS, COX-2, GFAP, and NF-κB expression in MCAO rats. It also increased the expression of bcl-2, and suppressed levels of bax and caspase-3 compared with the MCAO group. Our findings revealed that Triptolide exerts its neuroprotective effects against inflammation with the involvement of inhibition of NF-κB activation.

Bai S ，Hu Z ，Yang Y ，Yin Y ，Li W ，Wu L ，Fang M ... -  《-》

[Tripotolide ameliorates inflammation and apoptosis induced by focal cerebral ischemia/reperfusion in rats].

Bai S ，Sun Y ，Wu L ，Wu Z ，Fang M ... -  《-》

Triptolide inhibits COX-2 expression via NF-kappa B pathway in astrocytes.

Dai YQ ，Jin DZ ，Zhu XZ ，Lei DL ... -  《NEUROSCIENCE RESEARCH》

Isoquercetin attenuates oxidative stress and neuronal apoptosis after ischemia/reperfusion injury via Nrf2-mediated inhibition of the NOX4/ROS/NF-κB pathway.

Isoquercetin (Iso) has been found to have neuroprotective effects against cerebral ischemic stroke. However, the exact molecular mechanism underlying its neuroprotective ability remains unclear. In this study, we aimed to evaluate the neuroprotective effects of Iso in primary culture of rat hippocampal neurons exposed to oxygen and glucose deprivation and reperfusion (OGD/R) injury and in rats subjected to middle cerebral artery occlusion and reperfusion (MCAO/R) injury. We found that rats treated with Iso exhibited a lower degree of infarct volume, and brain water content than the vehicle-treated rats. Treatment with Iso also improved the neurological deficits in MCAO/R rats as shown by the decreased modified neurological severity score. Iso treatment decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) production, and increased the activity of superoxide dismutase (SOD) and catalase (CAT) in brains of MCAO/R rats and primary culture of rat hippocampal neurons exposed to OGD/R. Iso treatment prevents I/R-induced neuronal apoptosis in vivo and in vitro as indicated by increased cell viability and decreased number of TUNEL-positive cells, accompanying with downregulation of cleaved caspase-3 protein and upregulation of Bcl-2 protein. Moreover, Nrf2 knockdown weakened the anti-apoptotic and anti-oxidant activities of Iso in primary culture of rat hippocampal neurons exposed to OGD/R. Interestingly, we found that Iso could induce Nrf2 translocation from cytoplasm to nucleus in primary culture of rat hippocampal neurons exposed to OGD/R. Iso activated the NOX4/ROS/NF-κB signaling pathway in in vivo and in vitro cerebral I/R injury models. Nrf2 knockdown blocked the inhibitory effect of Iso on protein expression of NOX4, p-IκBα and p-p65 in primary culture of rat hippocampal neurons exposed to OGD/R. All the data suggested that Iso protected against oxidative stress and neuronal apoptosis in in vivo and in vitro cerebral I/R injury models via Nrf2-mediated inhibition of the NOX4/ROS/NF-κB signaling pathway. Our findings suggested that Iso could be a potential agent for I/R brain injury.

Dai Y ，Zhang H ，Zhang J ，Yan M ... -  《-》

Triptolide down-regulates COX-2 expression and PGE2 release by suppressing the activity of NF-κB and MAP kinases in lipopolysaccharide-treated PC12 cells.

As an active compound extracted from the Chinese herb Tripterygium wilfordii, triptolide (TP) was demonstrated to have potent antiinflammatory and immunosuppressive properties in previous studies. Recently, it has been shown that TP prevented the loss of dopaminergic neurons in the substantia nigra of rats in a model of Parkinson's disease, but little is known about the precise neuroprotective mechanism of TP. This study was designed to elucidate whether the neuroprotective effect of TP is partially based on its direct inhibition of inflammatory molecules by investigating the effects of TP on the expression of cyclooxygenase (COX)-2 and prostaglandin E2 (PGE2) related to the nuclear factor (NF)-κB pathway in lipopolysaccharide (LPS)-stimulated PC12 cells. The activation of related upstream molecules such as NF-κB, P38, extracellular signal-regulated kinase (ERK)1/2, and beta-alanyl-alpha-ketoglutarate transaminase (AKT), in PC12 cells were investigated by real time polymerase chain reaction (PCR), western blotting and enzyme-linked immunosorbent assay (ELISA). Our results showed that TP directly inhibited the expression of both mRNA and protein of COX-2 (p < 0.01), decreased PGE2 production (p < 0.01) in a dose-dependent manner, down-regulated NF-κB activity (p < 0.01), and significantly inhibited the phosphorylation of p38, ERK1/2 (p42/p44) and AKT in PC12 cells after LPS challenge. This suggests that the neuroprotective effects of TP may be partially mediated by direct inhibition of the expression of COX-2, activation of NF-κB, and phosphorylation of p38, ERK1/2 (p42/p44) and AKT proteins of neuronal cells.

Geng Y ，Fang M ，Wang J ，Yu H ，Hu Z ，Yew DT ，Chen W ... -  《-》