phytoestrogens and Dementia--Vascular

Oxidative stress is the major cause of neuronal cell degeneration observed in neurodegenerative diseases including vascular dementia (VaD), and hypertension has been found to increase the probability of VaD. Here, we investigated the effects of equol in deoxycorticosterone acetate (DOCA)-salt-induced hypertensive rats (DHRs) and the associated VaD. The systolic blood pressure of rats treated with low- (10 mg per kg body weight) and high-dose (20 mg per kg body weight) equol for 4 weeks was lower than that of the control group by 12.18 and 17.48% in a dose-dependent manner, respectively (p < 0.05), which was regulated by inhibiting angiotensin-converting enzyme (ACE) activity and increasing the nitric oxide (NO) production. Equol-treated DHRs showed a significant decrease in both the swimming distance and time required to reach the escape platform (78.20 to 82.56%, p < 0.05). In addition, the probe trial session and working memory test indicated that equol improved the long- and short-term memory of the rats. Moreover, the brain antioxidant activity was increased by elevating the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) levels, and the malondialdehyde (MDA) content and acetylcholinesterase (AChE) activity were decreased, indicating that equol suppressed oxidative stress. In conclusion, we demonstrated that equol exhibited comparable blood pressure (BP)-lowering and VaD-improving effects with the clinically used drug, lisinopril in DHRs while there was a positive correlation between the doses. Therefore, this bioactive compound may be useful for developing functional foods, thereby extending the application of equol-containing crops.

Topics: Acetylcholinesterase; Animals; Blood Pressure; Body Weight; Brain; Catalase; Dementia, Vascular; Desoxycorticosterone Acetate; Disease Models, Animal; Dose-Response Relationship, Drug; Equol; Glutathione Peroxidase; Hypertension; Malondialdehyde; Memory, Short-Term; Nitric Oxide; Oxidative Stress; Physical Conditioning, Animal; Phytoestrogens; Rats; Renin-Angiotensin System; Superoxide Dismutase; Swimming

Estrogen deficiency and increase in protein tyrosine phosphatase (PTPase) activity may be a key mechanism in postmenopausal dyslipidemia-induced vascular dysfunction and dementia. Thus, the present study has been designed to investigate the effect of biochanin A (BCA, a phytoestrogen) and sodium orthovanadate (SOV), an inhibitor of PTPase in dyslipidemia-induced vascular dementia in ovariectomized rats.. Female Wistar rats were ovariectomized and fed on high fat diet for 4 weeks to produce dyslipidemia. Dyslipidemia was assessed by estimation of serum lipid levels including total cholesterol, triglyceride, HDL, and LDL levels. Dementia was assessed in terms of increase in brain acetylcholinesterase (AChE) activity and attenuation of learning ability (escape latency time) and memory retention (time spent in target quadrant) using Morris water maze. Vascular dysfunction was assessed in terms of attenuation of acetylcholine-induced endothelium-dependent relaxation (isolated carotid ring preparation), mRNA expression of endothelial nitric oxide synthase, and increase in serum thiobarbituric acid reactive species, superoxide anion level. Neurodegeneration was assessed in hippocampus by hematoxylin and eosin staining. BCA (2.5 and 5 mg/kg) and SOV (5 and 10 mg/kg) were administered alone and in low-dose combination to ovariectomized dyslipidemic rats.. BCA (2.5 and 5 mg/kg), SOV (5 and 10 mg/kg), and donepezil (1 mg/kg) significantly improves vascular function, and learning and memory ability and decreases the neuronal cell death, oxidative stress, and AChE in ovariectomized dyslipidemic rats.. Thus, it may be concluded that BCA and SOV attenuate vascular dysfunction and dementia in dyslipidemic ovariectomized rats.

Topics: Acetylcholinesterase; Animals; Avoidance Learning; Brain; Dementia, Vascular; Donepezil; Dyslipidemias; Enzyme Inhibitors; Female; Gene Expression Regulation; Genistein; Indans; Lipids; Mental Recall; Nitric Oxide Synthase Type III; Ovariectomy; Oxidative Stress; Phytoestrogens; Piperidines; Rats; Rats, Wistar; Reaction Time; Vanadates