Infrared microspectroscopy of focally elevated creatine in brain tissue from amyloid precursor protein (APP) transgenic mice
Infrared microspectroscopy has been used to survey Alzheimer’s diseased brain tissue from a transgenic mouse model of the disease. Alzheimer’s disease is the leading cause of dementia among the elderly and is characterized by β-amyloid plaque deposition,neurofibrillary tangles, inflammation, and disturbed energy metabolism in the brain. Both the TgCRND8 and Tg19959 mouse models of the disease develop Alzheimer’s disease pathology beginning at approximately 3 months of age. Infrared microspectroscopy allows analysis of untreated, flash frozen tissue samples, at micron level spatial resolution, and was used in this study to examine creatine deposits in the Alzheimer’s diseased brain. Creatine is central to cellular energetics and plays an important role in proper brain function. The hippocampi of 7 pairs of transgenic mice and their littermate controls were mapped using infrared microspectroscopy and the results were analyzed for creatine levels and levels of β-sheet, indicative of the presence of β-amyloid plaques. Creatine was found to be focally elevated in the transgenic mice, as compared to their littermate controls but was not co-localized with β-amyloid plaques. Further surveys of serial sections from one transgenic mouse showed the 3-dimensional distribution of creatine within the sample. Focally elevated creatine may be a marker of the disease process, indicative of disturbed energy metabolism or inflammatory response to the disease progression.
Infrared microspectroscopy, Alzheimer's disease, creatine