(P25-019-24) Effects of Pinto Bean and Resistant Starch Supplementation on Memory and Cognition in an Estrogen Deficiency Mouse Model

Objectives: This study investigates the effects of pinto bean and resistant starch supplementation on short and long-term memory and cognitive function in estrogen deficient mice.

Methods: Three-month old C57BL/6 female mice were injected daily with vinyl cyclohexene dipoxide (VCD, 160 mg/kg bw in sesame oil) or vehicle (VH) for 30 days, after which estrogen deficiency was determined by vaginal cytology. Mice were then randomly assigned into three dietary groups (n=8/group): control (AIM-93M), 10% (wt/wt) pinto bean (PB), and resistant start (RS, similar fiber content as PB) for 12 wks. At the end of the dietary treatment, the mice went through a series of behavioral tests including the Open Field (OF) Maze, which examines general activity and the prevalence of stress, the Y-Maze, which examines short-term memory and exploration, and the Morris Water Maze (WMW), which examines learning ability, short and long-term memory, and cognitive functioning. Data were analyzed using linear and linear mixed models according to estrogen status (VCD vs VH) and diet as factors.

Results: No differences were observed in the OF Maze or Y-Maze between VCD and VH mice. RS mice tended (p=0.077) to travel faster in the OF Maze and spent more time in the novel arm (p=0.0003) of the Y-Maze. PB mice tended (p=0.06) toward the lowest latency to initial entry to the novel arm. PB-VH mice spent more time mobile (p=0.01) and travelled more distance (p=0.03) compared to the PB-VCD mice. No differences were observed between diet or estrogen status in the MWM 24-h probe trial. In the 72-h probe trial, VCD mice remained farther from the platform zone (p=0.05) and travelled less distance (p=0.03) in the quadrant containing the platform zone. These differences were primarily driven by the RS-VCD mice.

Conclusions: RS and PB supplemented mice exhibited better short-term memory and/or exploration behavior as indicated by the Y-Maze. In the MWM, VCD mice exhibited reduced long-term memory characteristics, primarily driven by the RS-VCD mice, which contrasts their performance in the other mazes. Ongoing work is examining differences in progressive learning ability/strategy, vaginal cytology, and neural and gene expression.

Funding Sources: NIH-NIA/NICCH (Award # R15AT011962) and Jim and Lynn Williams Professorship