Statins: Are they also memory enhancers? A study in relation to their hypocholesterolemic and antioxidant effects in Swiss albino mice

Abstract

Background: The most common cause of dementia with progressive loss of memory is Alzheimer’s disease (AD), a neurodegenerative disorder that occurs due to increased oxidative stress, deposition of amyloid protein, and loss of cholinergic neurons. Statins, by their hypocholesterolemic, antioxidant, and other activities may be helpful in this regard. Aims and Objectives: The aim of this study is to examine the relation between memory restoring effect, lipid lowering effect as well as the antioxidant properties of statins in experimental dementia models using Swiss albino mice. Materials and Methods: Cognitive ability was tested in randomly selected young Swiss albino mice with two exteroceptive behavioral models, passive avoidance paradigm, and Morris Water Maze (MWM) by assigning 30 animals divided equally into 5 groups for each model. Amnesia was induced by feeding high-fat-diet for 90 days in 4 groups of mice. The 5th group served as control with young mice. Piracetam, atorvastatin, and simvastatin were given, respectively, to 3 of the amnesic groups of each model whereas the 4th group treated with vehicle served as positive control. Results: Step-down latency was significantly higher in young mice as well as amnesic mice treated with piracetam, simvastatin, or atorvastatin in comparison to vehicle-treated amnesic mice. Similar result was also seen during retrieval test in MWM, although all the groups performed comparably during acquisition trial. Brain malondialdehyde (MDA) levels were significantly low in all the groups who performed well in either of the exteroceptive behavioral models. Cholesetrol levels in young control and statin-treated groups were significantly low in comparison to piracetam- or vehicle-treated mice. Conclusions: Atorvastatin and simvastatin improved the cognitive ability in terms of learning as well as retrieval of learned experience which may be attributed to their hypocholesterolemic and antioxidant properties.