Amanda R. Austin

Doctoral Dissertation Announcement

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Candidate: Amanda R. Austin

Degree of: Doctor of Philosophy

Department: Psychology

Title: Effects of Moderate Exercise on Spatial Memory in Rats Senesced with D-Galactose

Committee:
Dr. Lisa Baker, Chair
Dr. Wayne Fuqua
Dr. Cynthia Pietras
Dr. John Spitsbergen

Date: Monday, November 5, 2012 9:30 a.m. to 11:30 a.m.
3713 Wood Hall

Abstract:
Cognitive decline is a process frequently associated with aging in humans, as well as animals. Physical exercise appears to counteract cognitive decline, specifically spatial abilities, and decreases the effects of reactive oxygen species (ROS) associated with aging. In addition, brain derived neurotrophic factor (BDNF) and glial derived neurotrophic factor (GDNF) are well recognized as chemical mediators of the neurophysiological benefits of exercise.

In order to study the impact of exercise on spatial memory and neurotrophic factors, this study utilizes an animal model of accelerated aging involving chronic d-galactose administration. Specifically, previous research indicates daily injections of d-galactose for 6-10 weeks may increase ROS within an organism and produce significant deficits in learning and memory. The current study investigates d-galactose's ability to simulate aging by comparing chemically-senesced rats to age matched control rats. This study also further investigates the interaction between exercise, spatial abilities, and levels of BDNF and GDNF protein content within the hippocampus and pre-frontal cortex.

Forty-eight male Sprague-Dawley rats (24 chemically senesced and 24 age matched to chemically-senesced) are used. Half of the animals in each group are subjected to a moderate forced exercise regimen utilizing running wheels for eight weeks (13 m/min, 30 min, 3 days per week), while the remaining rats are exposed to the apparatus for the same amount of time, but with the wheels turned off. During this eight week period, rats receive once daily I.P. injection of d-galactose (100 mg/kg) or saline. Immediately following injections and exercise regimen, rats undergo a 19 day radial arm maze (RAM) procedure.  This procedure consists of two trials per day with a one hour inter-trial interval. Subsequently, rats are euthanized, brains are removed, and prefrontal cortex and hippocampal tissues are dissected and processed for analysis of BDNF and GDNF protein content using the ELISA assay. The results indicate spatial navigation performance is not significantly altered by d-galactose or by exercise. Furthermore, BDNF and GDNF protein content in the hippocampus or pre-frontal cortex does not differ among treatment groups.