ABSTRACT
BACKGROUND: Naoluo Xintong (NLXT) capsuleis a newly developed drug recorded in the Chinese Pharmacopoeia. It is derived from traditional Chinese medicine (TCM) NLXT decoction, and has been widely used to treat cerebrovascular diseases in clinic. However, it is currently unknown whether it improve cerebral ischemia reperfusion (I/R) injury. METHODS: The effect of NLXT on regional cerebral blood flow (rCBF) was examined using Laser Doppler flower. The Terminal deoxyribonucleotide transferase-mediated Nick end labeling (Tunel) assay was performed to determine the effects of NLXT on apoptosis. Subsequently, cerebral water content and TTC staining were measured to assess cerebral edema and infarct volume, respectively. The protein expression levels were analyzed with Immunofluorescence and western blot assays. RESULTS: The results indicated that NLXT ameliorated MCAO-induced cerebral I/R injury by decreasing infract volume, inhibition of apoptosis, and upregulation rCBF. In addition, it decreased the expression of key protein involved endoplasmic reticulum (ER)-stress, including glucose-regulated protein 78 (GRP78), C/EBP-homologous protein (CHOP) and Caspase-12 at 24 h following reperfusion. This was accompanied reduced degradation level of TRPC6 and increased phosphorylation of cAMP/Ca2+ response elementbinding protein (p-CREB), and decreased calpain-specific αII-spectrin breakdown product (SBDP145) activity. Interestingly, inhibition of mitogen-activated protein kinase (MEK) activity abolished the effect of NLXT on CREB activity. CONCLUSIONS: Collectively, the results indicated that NLXT can improve I/R injury therapy by activating TRPC6/MEK/CREB signaling pathway to attenuate ER-stress related neuronal apoptosis.
Subject(s)
Brain Ischemia , Reperfusion Injury , Animals , Apoptosis , Brain Ischemia/drug therapy , Endoplasmic Reticulum Stress , Rats , Reperfusion Injury/drug therapy , Signal TransductionABSTRACT
Tetramethylpyrazine (TMP, also known as Ligustrazine), which is isolated from Chinese Herb Medicine Ligustium wollichii Franchat (Chuan Xiong), has been widely used in China for the treatment of ischemic stroke by Chinese herbalists. Brain microvascular endothelial cells (BMECs) are the integral parts of the blood-brain barrier (BBB), protecting BMECs against oxygen-glucose deprivation (OGD) which is important for the treatment of ischemic stroke. Here, we investigated the protective mechanisms of TMP, focusing on OGD-injured BMECs and the Rho/Rho-kinase (Rho-associated kinases, ROCK) signaling pathway. The model of OGD-injured BMECs was established in this study. BMECs were identified by von Willebrand factor III staining and exposed to fasudil, or TMP at different concentrations (14.3, 28.6, 57.3 µM) for 2 h before 24 h of OGD injury. The effect of each treatment was examined by cell viability assays, measurement of intracellular reactive oxygen species (ROS), and transendothelial electric resistance and western blot analysis (caspase-3, endothelial nitric oxide synthase (eNOS), RhoA, Rac1). Our results show that TMP significantly attenuated apoptosis and the permeability of BMECs induced by OGD. In addition, TMP could notably down-regulate the characteristic proteins in Rho/ROCK signaling pathway such as RhoA and Rac1, which triggered abnormal changes of eNOS and ROS, respectively. Altogether, our results show that TMP has a strong protective effect against OGD-induced BMECs injury and suggest that the mechanism might be related to the inhibition of the Rho/ROCK signaling pathway.
Subject(s)
Blood-Brain Barrier/drug effects , Drugs, Chinese Herbal/pharmacology , Endothelial Cells/metabolism , Microvessels/drug effects , Pyrazines/pharmacology , Signal Transduction/drug effects , rho-Associated Kinases/metabolism , Animals , Blood-Brain Barrier/metabolism , Brain/drug effects , Brain/metabolism , Cells, Cultured , Endothelial Cells/drug effects , Glucose/metabolism , Male , Microvessels/metabolism , Nitric Oxide Synthase Type III/metabolism , Oxygen/metabolism , Protective Agents/pharmacology , Rats, Sprague-DawleyABSTRACT
To investigate the neuroprotective of ligustilide (LIG) against glutamate-induced apoptosis of PC12 cells, cell viability were examined by MTT assay. Flow cytometry was applied to assay cell apoptosis rate. Intracellular calcium concentration was measured by using fluorescent dye Fluo-3/AM. Cytochrome C (Cyt C), Caspase-3, Bax and Bcl-2 protein expression were assayed by western blot. The results showed that glutamate is cytotoxic with an inhibitory concentration 50 (ID50) of 15 mmol · L(-1). Pretreatment with LIG (1, 5, 15 µmol · L(-1)) significantly improved cell viability. The apoptosis rate in glutamate-induced PC12 cells was 13.39%, and decreased in the presence of LIG (1, 5, 15 µmol · L(-1)) by 9.06%, 6.48%, 3.82%, separately. Extracellular accumulation of Ca2+ induced by glutamate were significantly reduced by LIG. The results of western blot manifested that pretreatment LIG could decrease the release of Cyt C from mitochondria, down-regulate Caspase-3 protein expression and up-regulate Bcl-2/Bax ratio, thereby protects PC12 cells from apoptosis. In summary, LIG had protective effect on glutamate-induced apoptosis in PC12 cells through attenuating the increase in intracellular Ca2+ concentration, and inhibiting the release of Cyt C from mitochondria to cytoplasm.
