Protection against brain tissues oxidative damage as a possible mechanism for improving effects of low doses of estradiol on scopolamine-induced learning and memory impairments in ovariectomized rats

• Main Authors: Seyed Hassan Hejazian, Sareh Karimi, Mahmoud Hosseini, Seyed Mojtaba Mousavi, Mohammad Soukhtanloo
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2016-01-01
• Series: Advanced Biomedical Research
• Subjects: Estradiol; learning; memory; oxidative stress; scopolamine
• Online Access: http://www.advbiores.net/article.asp?issn=2277-9175;year=2016;volume=5;issue=1;spage=123;epage=123;aulast=Hejazian

Background: Regarding the anti-oxidative effects on the central nervous system, the possible protection against brain tissues oxidative damage as a possible mechanism for improving effects of low doses of estradiol on scopolamine-induced learning and memory impairments was investigated in ovariectomized (OVX) rats. Materials and Methods: The OVX rats treated by (1) vehicle, (2) scopolamine, and (3–4) scopolamine plus estradiol (20 or 20 or 60 μg/kg). Estradiol was administered (20 or 60 μg/kg, intraperitoneally) daily for 6 weeks after ovariectomy. The rats were examined for learning and memory using passive avoidance test. Scopolamine (2 mg/kg) was injected 30 min after training in the test. The brains were then removed to determine malondialdehyde (MDA) and thiol contents. Results: Scopolamine shortened the time latency to enter the dark compartment in (P < 0.01). Compared to scopolamine, pretreatment by both doses of estradiol prolonged the latency to enter the dark compartment (P < 0.01). The brain tissues MDA concentration as an index of lipid peroxidation was decreased (P < 0.05). Pretreatment by estradiol lowered the concentration of MDA, while it increased thiol content compared to scopolamine (P < 0.05 andP < 0.01). Conclusions: These results allow us to suggest a protection against brain tissues oxidative damage as a possible mechanism for improving effects of low doses of estradiol on scopolamine-induced learning and memory impairments in OVX rats.