thromboxane-b2 and Infarction--Middle-Cerebral-Artery

Elucidating action mechanisms of Chinese medicines has remained a challenging task due to the chemical and biological complexity that needs to be resolved. In this study we applied a gene expression data and connectivity map (CMAP) based approach to study action mechanisms of a Chinese medicine Xuesaitong injection (XST) on preventing cerebral ischemia-reperfusion injury. XST is a standardized patent Chinese medicine of Panax notoginseng roots and it has long been used for the effective prevention and treatment of stroke in China. However, more research is needed to understand the mechanisms underlying its effects against ischemic stroke. We first evaluated the effect of XST against ischemic stroke in an ischemia-reperfusion rat animal model and dissected its mechanisms based on gene expression data of injured brain. The results showed that treatment with XST significantly attenuated infarct area and histological damage. Based upon pathway analysis and the CMAP query of microarray data, anti-inflammatory response and anti-platelet coagulation were found as the major mechanisms of XST against stroke, which were further validated in vitro and with pharmacological assays of serum. We demonstrated the feasibility of applying the combination of the microarray with the CMAP in identifying mechanisms of Chinese medicine.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents; Brain; Cerebral Infarction; Drugs, Chinese Herbal; Gene Expression Profiling; Infarction, Middle Cerebral Artery; Macrophages; Male; Mice; Nerve Net; Nitric Oxide; Oligonucleotide Array Sequence Analysis; Platelet Aggregation; Rats, Sprague-Dawley; RAW 264.7 Cells; Real-Time Polymerase Chain Reaction; Reproducibility of Results; Saponins; Stroke; Thromboxane B2

This study is to investigate the effects of paeoniflorin on cerebral blood flow and the balance of PGI2/TXA2 of rats with focal cerebral ischemia-reperfusion injury. A total of 72 SD rats (3) were randomly divided into 6 groups: sham operation group, cerebral ischemia-reperfusion model group (I/R gourp), low (10 mg.kg-1), middle (20 mg.kg-1) and high (40 mg.kg-1) doses of paeoniflorin groups and nimrnodipine group. Focal cerebral ischemia in rats was made by inserting a monofilament suture into internal carotid artery for 90 min and then reperfused for 24 h. The effects of paeoniflorin on neurological deficit scores and the infarction volume of brain were detected. Relative regional cerebral blood flow (rCBF) was continuously monitored over ischemic hemispheres by laser-Doppler flowmetry (LDF). The expression of COX-2 in hippocampal CAl region was estimated by immunohistochemistry and the contents of prostacyclin I2 (PGI2), thromboxane A2 (TXA2), and ratio of PGIJ2/TXA2 in serum were measured by ELISA kits. Paeoniflorin significantly ameliorated neurological scores, reduced the infarction volume, and increased regional cerebral blood flow relative to the I/R group. In addition, paeoniflorin could inhibit COX-2 expression and the release of TXA2 and prevent the downregulation of PGI2 induced by I/R injury. The neuroprotective effects of paeoniflorin against focal cerebral ischemia-reperfusion rats might be attributed to improve the supply of injured hemisphere blood flow and adjust the balance between PGI2/TXA2.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Brain; CA1 Region, Hippocampal; Cyclooxygenase 2; Glucosides; Infarction, Middle Cerebral Artery; Male; Monoterpenes; Neuroprotective Agents; Paeonia; Plants, Medicinal; Random Allocation; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Reperfusion Injury; Thromboxane B2

The present study aimed to investigate the protective effects of injectable caltrop fruit saponin preparation (ICFSP) on ischemia-reperfusion injury in rat brain. Rats were injected with ICFSP and then subjected to cerebral ischemia-reperfusion injury induced by middle cerebral artery occlusion. Then the neurological deficit score was evaluated by Bederson's method. The infarct size was assessed by TTC staining. The content of malondialdehyde (MDA) and nitric oxide (NO), and the activity of superoxide dismutase (SOD) in rat cerebrum were measured with kits, and the content of 6 K prostaglandin F1α (6-K-PGF 1α), thromboxane B2 (TXB2) and endothelin (ET) in blood plasma was measured by radioimmunoassay. The results demonstrated that ICFSP led to a decrease in infarct size (p < 0.01), neurological deficit score (p < 0.05) and plasma content of TXB2 and ET (p < 0.05), and an increase of the plasma level of 6-K-PGF 1α (p < 0.05) and SOD activity in cerebrum, where the MDA and NO content were decreased. The treatment improved forelimb function. ICFSP showed a similar potency compared to that of Ligustrazine hydrochloride parenteral solution (LHPS) and nimodipine (Nim). We concluded that ICFSP protects the brain damage caused by ischemia-reperfusion injury in rats, and this may be closely related to the regulation of reactive oxygen species (MDA and SOD activity) and NO levels in the rat cerebrum, as well as vasoactive factors in the plasma (6-K-PGF 1α, TXB2 and ET).

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents; Calcium Channel Blockers; Cerebral Infarction; Cerebrum; Endothelins; Forelimb; Fruit; Infarction, Middle Cerebral Artery; Injections; Male; Malondialdehyde; Neuroprotective Agents; Nitric Oxide; Phytotherapy; Plant Extracts; Rats; Rats, Wistar; Reperfusion Injury; Saponins; Superoxide Dismutase; Thromboxane B2; Tribulus

The post-treatment effects of the selective cyclooxygenase (COX)-2 inhibitor, valdecoxib, were investigated in a rat model of temporary focal ischemia. Valdecoxib reduced basal brain prostaglandin E(2) concentrations at dosages that did not affect serum thromboxane B(2), consistent with a selective COX-2 effect. Temporary focal cerebral ischemia was produced in rats by middle cerebral artery occlusion for 90 min. There was increased expression of COX-2 protein detected by Western blot and immunocytochemistry within neurons in the ischemic cortex at 4 and 24 h after ischemia. Rats were treated with vehicle or valdecoxib 15 min before or 1.5, 3 and 6 h after cerebral ischemia. Rats were sacrificed and brain infarction volume determined 24 h after ischemia. Valdecoxib treatment was associated with a decrease in infarction volume when administered 15 min before, and 1.5 or 3 h but not 6 h after cerebral ischemia. There were no differences in physiological parameters during the procedure. Valdecoxib administered at 1.5 h after ischemia significantly reduced the concentrations of prostaglandin E(2) in ischemic penumbral cortex as compared to the vehicle-treated group and contralateral non-ischemic cortex. These results suggest that COX-2 inhibition with valdecoxib is effective when initiated both before and after middle cerebral artery occlusion.

Topics: Animals; Blood Pressure; Body Temperature; Brain; Cerebrovascular Circulation; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Dinoprostone; Dose-Response Relationship, Drug; Hippocampus; Infarction, Middle Cerebral Artery; Isoxazoles; Male; Neurons; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Sulfonamides; Thromboxane B2; Time Factors

Inosine is a naturally occurring nucleoside degraded from adenosine. Recent studies have demonstrated that inosine has potent immunomodulatory and neuroprotective effects. In the present study, we further investigated the inhibitory effects of inosine on platelet activation in vitro and in vivo, as well as in attenuating middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia in rats.. Inosine concentration-dependently (0.5 to 6.0 mmol/L) inhibited platelet aggregation stimulated by agonists. Inosine (1.5 and 3.0 mmol/L) inhibited phosphoinositide breakdown, [Ca+2]i, and TxA2 formation in human platelets stimulated by collagen (1 microg/mL). In addition, inosine (1.5 and 3.0 mmol/L) markedly increased levels of cyclic guanylate monophosphate (GMP) and cyclic GMP-induced vasodilator-stimulated phosphoprotein Ser157 phosphorylation. Rapid phosphorylation of a platelet protein of molecular weight 47,000 (P47), a marker of protein kinase C activation, was triggered by collagen (1 microg/mL). This phosphorylation was markedly inhibited by inosine (3.0 mmol/L). Inosine (1.5 and 3.0 mmol/L) markedly reduced hydroxyl radical in collagen (1 microg/mL)-activated platelets. In in vivo studies, inosine (400 mg/kg) significantly prolonged the latency period of inducing platelet plug formation in mesenteric venules of mice, and administration of 2 doses (100 mg/kg) or a single dose (150 mg/kg) of inosine significantly attenuated MCAO-induced focal cerebral ischemia in rats.. Platelet aggregation contributes significantly to MCAO-induced focal cerebral ischemia. The most important findings of this study suggest that inosine markedly inhibited platelet activation in vitro and in vivo, as well as cerebral ischemia. Thus, inosine treatment may represent a novel approach to lowering the risk of or improving function in thromboembolic-related disorders and ischemia-reperfusion brain injury.

Topics: Animals; Brain Ischemia; Calcium; Cell Adhesion Molecules; Collagen; Contrast Media; Cyclic AMP; Cyclic GMP; Fluorescein; Free Radical Scavengers; Humans; Infarction, Middle Cerebral Artery; Inosine; Male; Mice; Microcirculation; Microfilament Proteins; Phosphatidylinositols; Phosphoproteins; Phosphorylation; Platelet Aggregation; Platelet Aggregation Inhibitors; Protein Kinase C; Rats; Rats, Wistar; Thrombosis; Thromboxane B2

Platelet activation and subsequent aggregation play a key role in the pathogenesis of ischemic brain damage. Recent studies revealed that enhanced platelet activation is also observed after ischemia, suggesting that secondary thrombus formation might participate in the development of cerebral infarction. The binding of platelet glycoprotein GPIIb/IIIa (integrin alpha(IIb)beta3) to fibrinogen is the final common pathway in platelet aggregation. Therefore, GPIIb/IIIa antagonists might be useful in acute ischemic stroke as well as in the secondary prevention of ischemic stroke. In the present study, we evaluated the effect of three compounds, FK419 ((S)-2-acetylamino-3-[(R)-[1-[3-(piperidin-4-yl) propionyl] piperidin-3-ylcarbonyl] amino] propionic acid trihydrate), a novel nonpeptide GPIIb/IIIa antagonist, ozagrel, a selective thromboxane A(2) synthase inhibitor, and argatroban, a thrombin inhibitor, on middle cerebral artery (MCA) patency and ischemic brain damage using photochemically induced MCA thrombosis model in guinea pigs. FK419, ozagrel, or argatroban was administered 5 min after the termination of photoirradiation. FK419 dose-dependently improved MCA patency by decreasing the total occlusion time, time to continuous reperfusion, and the number of cyclic flow reductions, at doses that inhibited ADP-induced platelet aggregation ex vivo. In contrast, ozagrel only improved total occlusion time, and argatroban showed no improvement in MCA patency. FK419 also reduced ischemic brain damage in a dose-dependent fashion, whereas ozagrel and argatroban did not. Finally, FK419 ameliorated neurological deficits, whereas ozagrel and argatroban did not. These results indicate that FK419, a GPIIb/IIIa antagonist, ameliorates ischemic brain damage by improving MCA patency after occlusion and that FK419 is a promising candidate for the treatment of acute ischemic stroke.

Topics: Animals; Antithrombins; Arginine; Blood Coagulation; Blood Platelets; Brain Ischemia; Disease Models, Animal; Guinea Pigs; Infarction, Middle Cerebral Artery; Male; Methacrylates; Pipecolic Acids; Platelet Aggregation Inhibitors; Platelet Glycoprotein GPIIb-IIIa Complex; Reperfusion Injury; Sulfonamides; Thromboxane B2