The Effect of an Antioxidant Supplement on a Mouse Model of Alzheimer’s Disease

Student: Jennifer Grossmann
Major: Cognitive Behavioral Neuroscience
Advisors: Dr. Amy Jo Stavnezer, Dr. Susan Clayton
Alzheimer’s Disease (AD) is a neurodegenerative disorder that causes abnormal cellular processes in the brain leading to behavioral changes such as progressive memory loss, reduced inhibition, and decreased motor functions. Previous research has explored treatment options such as behavioral therapies or altered diets. The current study aims to determine the effectiveness of an over-the-counter antioxidant supplement on AD in a mouse model. It was hypothesized that supplementation to mice genetically manipulated to show AD would improve their learning and memory in standard rodent behavioral tests. Unfortunately, there was no significant effects of the antioxidant supplement in this study. Although it was not found to induce changes in the behavior of the mice, perhaps adjustments in the length of time or start time of supplementation could result in the positive effects in mice that could then be used in humans with AD.

Description

Alzheimer’s Disease (AD) affects approximately 5.8 million people in the United States alone, and deaths from the disease increased 145% from 2000 to 2017 (Alzheimer’s Association). Based on current trends, there are projected to be about 89 million people over the age of 65 in the US alone by 2050. The disease is biologically characterized by a buildup of amyloid‐β proteins and tau tangles which form plaques in the brain and disturbs proper functioning (Fuhrmann et al., 2010; Herman et al., 2019). These changes in the brain result in cognitive deficits such as incremental memory loss, confusion, disorientation, or wandering (Logsdon et al., 1998).
Dietary supplements have shown great promise as a form of treatment for AD. Specifically, supplement of antioxidants combat oxidative stress and reduce chronic inflammation, both of which plague those with AD.  An over-the-counter dietary supplement comprised of five herbal ingredients including silymarin from milk thistle (Silibum marianum), bacopa extract (Bacopa monniera), ashwagandha (Withania somnifera), green tea extract (Camilia sinesis), and curcumin from turmeric (Curcuma longa) was tested in this experiment.  It has been shown to produce beneficial effects of antioxidants such as reducing oxidative stress, by means of increasing antioxidant enzyme expression.
Currently, no published research has investigated the direct impact of this supplement on AD in a mouse model. The following study explores the potential preventative effects of the phytochemical mixture on a mouse model of AD.  Learning, memory, and anxiolytic behaviors were tested with a standard spatial learning task, the Morris water maze, and an activity and anxiety test, the open field.
Though all groups did show the ability to learn and store spatial memories in the Morris water maze, there was no benefit of the dietary supplement. It is possible this antioxidant does not interact with mouse cells in the exact way that was theorized or needs to be supplemented at a different dose range. There is still a potential for antioxidant supplements to improve deficits due to Alzheimer’s Disease, for instance the Mediterranean diet, which is full of natural antioxidants seems promising, and perhaps a different dietary supplement could produce positive results.
Jennifer will be online to field comments on May 8:
10am-noon EDT (Asia: late evening, PST 6am-8am, Africa/Europe: late afternoon)

Posted in I.S. Symposium, Independent Study on May 4, 2020.