P 63 a ISSRNS 2012: Abstracts / Synchrotron Radiation in Natural Science Vol. 11, No 1 – 2 (2012)
EVALUATION OF THE VARIABILITY IN ELEMENTAL COMPOSITION OF DOPAMINEGRIC NEURONS IN SENILE BRAINS USING
SYNCHROTRON RADIATION BASED X-RAY FLUORESCENCE
M. Szczerbowska-Boruchowska1∗, P. Wrobel1, A. Sorowka1, E. Radwanska2, and D. Adamek2
1AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. Mickiewicza 30, 30–059 Krakow, Poland
2Department of Neuropathology, Chair of Pathomorphology, Faculty of Medicine, Jagiellonian University Medical College, ul. Botaniczna 3, 31–503 Krakow, Poland
Keywords: synchrotron radiation, X-ray fluorescence, senile brains, substantia nigra, elemental microimaging
∗e-mail : Magdalena.Boruchowska@fis.agh.edu.pl
A major risk factor for neurodegenerative diseases such as Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, Alzheimer’s disease and progressive supranuclear palsy is ag- ing [1]. Multiple reports have documented an age- related loss of the pigmented neurons in the sub- stantia nigra (SN) and other nigrostriatal structures of human brain. Two processes that have been im- plicated in aging are free radical-induced oxidative damage and mitochondrial dysfunction [1]. Trace elements especially metals play important role in the mentioned processes [2] and may induce signif- icant cellular disturbances when present in excess concentrations. To address the questions related to chemical composition of dopaminergic neurons in senile brains and their age-related alterations, a combination of imaging and spectroscopic tech- niques is needed. For this purpose synchrotron ra- diation x-ray fluorescence (SRXRF) was used for two-dimensional imaging of elements in human sub- stantia nigra.
The autopsy samples of SN of human senile brains were taken. The specimens were frozen and
Figure 1 : X-ray fluorescence maps of substantia nigra cryo-section taken from senile human brain. Arrows show neuron bodies. Scale bar: 60 µm.
cut into 20 µm-thick slices with the use of a cry- omicrotome. The tissue slices were mounted im- mediately onto ultralene films and freeze-dried at
−80◦C.
The SRXRF measurements were carried out at the 7T-WLS/1 (mySpot) beamline of the Electron Storage Ring BESSY II (Berlin, Germany). The primary photon energy was set to 17 keV. Capillary optics was used to focus the X-ray beam on the sam- ple surface to spot sizes of about 10 µm in diameter.
The sample areas were scanned point by point with the step sizes equal to 10 µm both horizontally and vertically. The time of acquisition for tissue sam- ples was equal to 10 s per one measurement point.
The characteristic X-ray lines were measured by 7 element Si(Li) detector. The SRXRF analysis al- lowed for finding P, S, Cl, K, Ca, Fe, Cu, Zn, Se, Br, Rb and Sr in the samples investigated. The ex- amples of the SRXRF maps of selected elements for SNc section are shown in Figure 1. The location of nerve cells is precisely visualized by the high levels of most elements in the scanned areas of the tissues.
In each case two areas were chosen for the quan- titative analysis, i.e. nerve cell bodies and the ex- traneuronal spaces. It was found that the nerve cells from different samples reveal the biggest sim- ilarity in terms of phosphorus content. Whilst, the mass fractions of Cu differentiate neurons origi- nating from various samples in the largest extent.
The higher variation in elemental composition is observed between extraneuronal spaces of different samples than within nerve cells.
Acknowledgments: This work was supported by the Polish Ministry of Science and Higher Education and its grants for Scientific Research as well as European Com- munity’s Seventh Framework Programme (FP7/2007- 2013) under grant agreement n◦226716.
References
[1] D.S. Albers, M.F. Beal, “Mitochondrial dysfunction and oxidative stress in aging and neurodegenerative disease,” J. Neural Transm. Suppl. 59 (2000) 133.
[2] K. Jomova, D. Vondrakova, M. Lawson, M Valko.
“Metals, oxidative stress and neurodegenerative dis- orders,” Mol. Cell. Biochem. 345 (2010) 91.
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