Osthole, a natural coumarin improves cognitive impairments and BBB dysfunction after transient global brain ischemia in C57 BL/6J mice: involvement of Nrf2 pathway.

Oxidative stress and blood-brain barrier (BBB) disruption play important roles in cerebral ischemic pathogenesis and may represent targets for treatment. Earlier studies have shown that osthole, a main active constituent isolated from Cnidium monnieri (L.) Cusson, could be considered as an attractive therapeutic agent in the treatment of ischemic stroke. However, the mechanism underlying the protective effect remains vague. In this study we aimed to investigate the effect of osthole on transient cerebral ischemia as well as its mechanism(s) in C57 BL/6 J mice. Mice were subjected to transient global cerebral ischemia induced by bilateral common carotid artery occlusion for 25 min. Behavioral test was performed at 4 days after ischemia, followed by assessment of neuronal loss in hippocampal CA1 region. Osthole significantly improved the cognitive ability and enhanced the survival of pyramidal neurons in the CA1 region of mice after lesion. Further studies showed that osthole attenuated the permeation of BBB, which may contribute to antioxidative effect by increasing the superoxide dismutase activity and decreasing the malondialdehyde level in model mice. Further studies revealed that osthole obviously up-regulated the protein levels of nuclear factor erythroid 2-related factor 2/heme oxygenase 1 in HT22 cells. In conclusion, our findings indicated that osthole exerts neuroprotective effects against global cerebral ischemia injury by reducing oxidative stress injury and reserving the disruption of BBB, which may be attributed to elevating the protein levels of Nrf2 and HO-1.

Anti-inflammatory effect and mechanism of osthole in rats.

OBJECTIVE: To investigate the anti-inflammatory effect and mechanism of osthole (Ost). METHODS: Carrageenan -induced hind paw edema in rats were prepared. The nitric oxide synthase (NOS) activity was measured by NADPH -diaphoras stain assay, nitric oxide (NO) content by Griess diazotization assay, malondialdehyde (MDA) content by Thibabituric acid mehtods. And PG content was assaied by Uv -vis spectrophotometry with 278 nm after 0.5 mol/L KOH methanol reagent dissimilating. RESULTS: The increase in NO2(-) observed 4h after carrageenan administration was inhibited by Ost from 524.4 +/- 58.7/micromol/L(-1) NO2(-) for carrageenan alone to 461.5 +/- 68. 8,353.8 +/- 111.0/micromol/L NO2(-) for, respectively, carrageenan administered in combination with 50 mg/kg or 100 mg/kg Ost. It suggested Ost suppress inflammatory responses on NO levels in a dose -dependent manner (P < 0.05). In the presence of Ost 100 mg/kg, NOS activities remained at near blank control levels. Meanwhile results showed reduced malondialdehyde production (MDA) in the presence of Ost, which is one of the byproducts of lipid peroxidation. Ost 50, 100 mg/kg markedly suppressed the generation of PG in inflamed paws. CONCLUSION: Ost presents anti-inflammatory activities at the used models. The effects may be associated to a supression of content of PG, NO, MDA and cNOS activity by inhibition of calcium entry and elevating cGMP levels way.

[Calcium antagonistic effect of Xanthotoxol on isolated guinea pig atria].

OBJECTIVE: To study the mechanism of depressant effect of xanthotoxol (XT) on contractility in the isolated guinea pig atria. METHODS: The contractile force of the isolated left atria was determined by tension recording method. RESULTS: In the experiments on contractility of the left atria XT and Verapamil (Ver) significantly depressed the positive staircase phenomena, which was reversed by Ver but not by XT. However, the post-rest potentiation of myocardial contraction in the left atria was only markedly decreased by XT but not by Ver. Furthermore, XT not only attenuated the positive inotropic action, but also delayed the following toxicity response induced by ouabain in the isolated left atria. CONCLUSION: XT blocked not only the voltage dependent calcium channel, but also the receptor operated calcium channel in the isolated guinea pig atria.

[Effect of xanthnotoxol on contraction of rabbit thoracic aortic strips].

OBJECTIVE: To study the effect of xanthnotoxol (XT) on contractility of rabbit thoracic aorta strips and its relationship with Ca2+. METHODS: Routine experimental methods for isolated thoracic aorta strips were adopted. RESULTS: XT and verapamil (Ver) can make the dose-response curve of rabbit thoracic aorta strips induced by NE, KCl, CaCl2 shifed right (the pD'2 of KCl and CaCl2 value was 3.58 +/- 0.07 and 4.12 +/- 0.12) and depressed the maximal responses. Like verapamil (Ver), it is accomplished by calcium antagonism. XT could selectively block the voltage dependence calcium channel (VDC), and have no effect on the receptor operated calcium channel (ROC). CONCLUSION: It suggested XT had selectly blocking effect on voltage dependence calcium channel.

Osthole, a natural coumarin, improves neurobehavioral functions and reduces infarct volume and matrix metalloproteinase-9 activity after transient focal cerebral ischemia in rats.

Previously we demonstrated that Osthole, a natural coumarin, protects against focal cerebral ischemia/reperfusion-induced injury in rats. In the present study, the effects of Osthole on neurobehavioral functions, infarct volume and matrix metalloproteinase-9 (MMP-9) in a rat 2h focal cerebral ischemia model were investigated. Osthole (100mg/kg per dose) was administrated intraperitoneally 30min before ischemic insult and immediately after reperfusion. Osthole treatment significantly reduced neurological deficit score and infarct volume by 38.5% and 33.8%, respectively, as compared with the untreated animals. Osthole reversed ischemia-reperfusion-induced increase in MMP-9 protein level/activity as evidenced by Western blotting and gelatin zymography. Taken together, these results for the first time demonstrate that Osthole reduces infarct volume, restores neurobehavioral functions and downregulates MMP-9 protein level/activity in ischemia/reperfused brain.