Amelioration of cognitive deficits by Spirulina platensis in L-methionine-induced rat model of vascular dementia

Background: Vascular dementia (VaD) is an age-associated highly prevalent brain disorder characterized by progressive cognitive insufficiency. Nutritional deprivation-associated rise in homocysteine (HCy), dyslipidemia, endothelial debility, and redox imbalance is a key facet of VaD. Spirulina platensis (spirulina) is a high-nutritional-value cyanobacterium appreciated by modern as well as diverse civilizations of antiquity (e.g., Mexican-Aztec, African-Kanambous). The present study aims to investigate the therapeutic effects of spirulina (S. platensis) in VaD. Materials and Methods: L-methionine (1.7 g/kg) was given orally to simulate VaD in rats. Spirulina was administered (0.5, 1, and 2 g/kg; p.o.) for 4 weeks daily. The neurobehavioral assessments and biochemical analysis in the whole brain (thiobarbituric acid-reactive substances [TBARS], glutathione [GSH], and acetylcholinesterase [AChE]) and serum (cholesterol, HCy, and nitrite) of rats were conducted. Results: Cognitive impairment in rats by L-methionine was attributable to statistically significant (P < 0.05) elevation in HCy, cholesterol levels, oxidative stress, AChE activity, and a decline of endothelial-derived nitric oxide. Spirulina attenuated (P < 0.05) the L-methionine-triggered cognitive insufficiency in rats. TBARS levels and AChE activity were reduced and GSH content was increased by spirulina in the brain of L-methionine-treated rats. Spirulina-attenuated L-methionine triggered increase in blood HCy and total cholesterol levels in rats. In aortic-ring tests, acetylcholine-induced endothelium-dependent relaxation was abolished by L-methionine, which showed endothelial mutilation and was potently attenuated by chronic treatment with spirulina. Conclusion: In L-methionine model of VaD, therapeutic intervention by spirulina (S. platensis) imparts appreciable relief in cognitive deficits.