Amelioration of Cognitive Deficits by Spirulina platensis in L‑methionine‑Induced Rat Model of Vascular Dementia

Abstract

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.

Keywords: Dementia; endothelial dysfunction; homocysteine; L‑methionine; oxidative stress; spirulina