astaxanthine and Stroke

Excitotoxicity and oxidative stress are central to the pathology of the nervous system, and inhibition of excitotoxicity induced by glutamate is one of the therapeutic goals determined for stroke. The present study aimed to investigate the effects of Astaxanthin, a potent natural antioxidant, on complications caused by acute cerebral stroke. In this research, 60 male Wistar rats were used which were divided into 5 groups as follow: (1) the sham group (vehicle), (2) the ischemic control group (vehicle), and the ischemic groups treated by Astaxanthin with doses of 25, 45, and 65 mg/kg. In the ischemic groups, ischemic model was performed by middle cerebral artery occlusion (MCAO) method, and the Astaxanthin administration was carried out after the artery occlusion and before opening the artery. The obtained results indicated that Astaxanthin could significantly reduce stroke volume, neurological deficits, and lipid peroxidation. Moreover, it was able to restore total oxidant status (TOS) and caspase 3 level to the normal level. The activity of antioxidant enzyme glutathione peroxidase (GPX), and the expression of catalase, GPx and nuclear factor kappa B (NFκb) genes, which were reduced after ischemia, were increased. This phenomenon was particularly pronounced for glutamate transporter 1 (GLT-1). Furthermore, Astaxanthin decreased the augmented pro-apoptotic gene Bax and restored the reduced Bcl2 expression to the normal level. Significant effects on the P53 and PUMA expression were not observed. Overall, the medium dosage of Astaxanthin appears to be more effective in reducing the complications of ischemia, particularly on our major study endpoints (stroke volume and neurological defects). Longer studies with a more frequent administration of Astaxanthin are required to better understand the precise mechanism of Astaxanthin.

Topics: Animals; Antioxidants; Brain Injuries; Brain Ischemia; Disease Models, Animal; Infarction, Middle Cerebral Artery; Male; Neuroprotective Agents; Rats; Rats, Wistar; Reperfusion; Reperfusion Injury; Stroke; Xanthophylls

Astaxanthin, a natural antioxidant carotenoid, has been shown to reduce cerebral ischemic injury in rodents. However, there have not been any studies specifically addressing whether preventive administration of astaxanthin can protect against cerebral ischemia. The purpose of this study was to examine whether pretreatment of astaxanthin can protect against ischemic injuries in the adult rats. The rats were pre-administered intragastrically with astaxanthin for seven days (once a day), and middle cerebral artery occlusion was performed at 1h after the final administration. It was found that astaxanthin prevented neurological deficits and reduced cerebral infarction volume. To evaluate the mechanisms underlying this protection, brain tissues were assayed for free radical damage, antioxidant gene expression, cell apoptosis and regeneration. The results showed that the mechanisms involved suppression of reactive oxygen species, activation of antioxidant defense pathway, and inhibition of apoptosis as well as promotion of neural regeneration. Astaxanthin did not alter body weights and the protective effect was found to be dose-dependent. Collectively, our data suggest that pretreatment of astaxanthin can protect against ischemia-related damages in brain tissue through multiple mechanisms, hinting that astaxanthin may have significant protective effects for patients vulnerable or prone to ischemic events.

Topics: Animals; Antioxidants; Apoptosis; Brain Ischemia; Cell Death; Male; Neuroprotective Agents; Rats, Sprague-Dawley; Reactive Oxygen Species; Stroke; Xanthophylls

It is known that vitamin E and some carotenoids have antioxidant activities that alleviate endothelial dysfunction and play a protective role against cardiovascular disease. The current study was designed to examine the hypothesis that astaxanthin, a red pigment carotenoid found in salmonid and crustacean aquaculture, protects stroke-prone spontaneously hypertensive rats (SHRSP) from vascular oxidative damage, hypertension, and cerebral thrombosis. Male 6-week-old SHRSP were classified into 4 groups: a control group, 2 astaxanthin groups, and a vitamin E group. The treated animals were given either astaxanthin or vitamin E for 3 weeks. Body weights in each group were not significantly different from control group during the treatment period, but the usual increase in systolic blood pressure in SHRSP observed with age was significantly suppressed by treatment. Thrombogenesis, assessed using a helium-neon (He-Ne) laser technique in pial blood vessels, together with antioxidant activity, assessed by measuring urinary 8-OHdG levels, were significantly moderated. Urinary nitric oxide (NO) metabolites were increased after treatment. These results supported our hypothesis and strongly suggested that the antithrombotic and antihypertensive effects of astaxanthin or vitamin E may be related to an increase in bioavailable NO, possibly mediated by decreased inactivation of NO by reactive oxygen species.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antihypertensive Agents; Antioxidants; Cardiovascular Diseases; Deoxyguanosine; Dose-Response Relationship, Drug; Fibrinolytic Agents; Hypertension; Intracranial Thrombosis; Male; Nitrates; Nitric Oxide; Nitrites; Oxidative Stress; Rats; Rats, Inbred SHR; Risk Factors; Specific Pathogen-Free Organisms; Stroke; Xanthophylls

Astaxanthin is a natural antioxidant carotenoid that occurs in a wide variety of living organisms. We investigated, for the first time, antihypertensive effects of astaxanthin (ASX-O) in spontaneously hypertensive rats (SHR). Oral administration of ASX-O for 14 d induced a significant reduction in the arterial blood pressure (BP) in SHR but not in normotensive Wistar Kyoto (WKY) strain. The long-term administration of ASX-O (50 mg/kg) for 5 weeks in stroke prone SHR (SHR-SP) induced a significant reduction in the BP. It also delayed the incidence of stroke in the SHR-SP. To investigate the action mechanism of ASX-O, the effects on PGF(2alpha)-induced contractions of rat aorta treated with NG-nitro-L-arginine methyl ester (L-NAME) were studied in vitro. ASX-O (1 to 10 microM) induced vasorelaxation mediated by nitric oxide (NO). The results suggest that the antihypertensive effect of ASX-O may be due to a NO-related mechanism. ASX-O also showed significant neuroprotective effects in ischemic mice, presumably due to its antioxidant potential. Pretreatment of the mice with ASX-O significantly shortened the latency of escaping onto the platform in the Morris water maze learning performance test. In conclusion, these results indicate that astaxanthin can exert beneficial effects in protection against hypertension and stroke and in improving memory in vascular dementia.

Topics: Animals; Antihypertensive Agents; Aorta, Abdominal; beta Carotene; Blood Pressure; Hypertension; In Vitro Techniques; Male; Neuroprotective Agents; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Rats, Wistar; Stroke; Vasodilation; Xanthophylls