A blueberry-enriched diet provides cellular protection against oxidative stress and attenuates a kainate-induced learning impairment in rats

Authors: DUFFY, KARA - NIA/NIH; SPANGLER, EDWARD - NIA/NIH; DEVAN, BRYAN - NIA/NIH; GUO, ZHIHONG - NIA/NIH; BOWKER, JONNA - NIA/NIH; JANAS, ANNE - NIA/NIH; HAGAPANOS, ADRIENNE - NIA/NIH; MINOR, ROBIN - NIA/NIH; DECABO, RAFAEL - NIA/NIH; MOUTON, PETER - NIA/NIH; Shukitt-Hale, Barbara; Joseph, James; INGRAM, DONALD - NIA/NIH

Submitted to: Neurobiology of Aging
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2007
Publication Date: 11/1/2008
Citation: Duffy, K.B., Spangler, E.L., Devan, B.D., Guo, Z., Bowker, J.L., Janas, A.M., Hagapanos, A., Minor, R.K., Decabo, R., Mouton, P.R., Shukitt Hale, B., Joseph, J.A., Ingram, D.K. 2008. A blueberry-enriched diet provides cellular protection against oxidative stress and attenuates a kainate-induced learning impairment in rats. Neurobiology of Aging. 29:1680-1689.

Interpretive Summary: Young rats were fed either a blueberry supplemented diet or a control diet not containing blueberry for at least eight weeks. They then received injections of kainic acid, which stimulates brain degeneration, or saline into both sides of the brain. One week later rats were trained on a complex maze with documented sensitivity to region of the brain involved in memory. Based on analyses of several variables, the kainic acid treated rats exhibited clearly impaired learning performance; however, the blueberry diet significantly lessened this impairment. Supporting the behavioral findings, the kainic acid treated rats on the control diet showed greater brain cell loss compared to the kainic acid treated rats on the blueberry diet. Also, cells were grown supplemented with fluid from either the rats fed the blueberry or control diet. The cells grown with the fluid from the rats fed the blueberry diet had enhanced survival after exposure to an oxidative stressor. These findings suggest that blueberry supplementation may protect against brain degeneration and cognitive impairment.

Technical Abstract: Young male Fischer-344 rats were fed a diet containing 2% blueberry (BB) extract or control diet for at least 8 weeks and then received bilateral hippocampal injections of kainic acid (KA 200 ng/0.5µl) or phosphate buffered saline (PBS). One week later rats were trained in one-way active footshock avoidance in a straight runway followed the next day by training in a footshock motivated 14-unit T-maze with documented sensitivity to hippocampal gluatamatergic damage. Based on analyses of several performance variables, KA-treated rats exhibited clearly impaired learning performance; however, the BB diet significantly attenuated this impairment. Supporting the behavioral findings, stereological assessment of CA1 pyramidal neurons documented greater neuronal loss in KA-treated controls compared to KA-treated rats on the BB diet. In an in vitro experiment, FaO cells grown in medium supplemented with serum from BB-fed rats had enhanced viability after exposure to hydrogen peroxide. These findings suggest that BB supplementation may protect against neurodegeneration and cognitive impairment mediated by oxidative stress.