Amyloid β-protein (Aβ) is known as a key molecule related to the pathogenesis of Alzheimer’s disease (AD). Over time, the amyloid cascade disrupts essential function of mitochondria including Ca²⁺ homeostasis and reactive oxygen species (ROS) regulation, and eventually leads to neuronal cell death. However, there have been no methods that analyze and measure neuronal dysfuction in pathologic conditions quantitatively. Here, we suggest a cell-based optical assay to investigate neuronal function in AD using femtosecond-pulsed laser stimulation. We observed that laser stimulation on primary rat hippocampal neurons for a few microseconds induced intracellular Ca²⁺ level increases or produced intracellular ROS which was a primary cause of neuronal cell death depending on delivered energy. Although Aβ treatment alone had little effect on the neuronal morphologies and networks in a few hours, Aβ-treated neurons showed delayed Ca²⁺ increasing pattern and were more vulnerable to laser-induced cell death compared to normal neurons. Our results collectively indicate that femtosecond laser stimulation can be a useful tool to study neuronal dysfuction related to AD pathologies. We anticipate this optical method to enable studies in the early progression of neuronal impairments and the quantitative evaluation of drug effects on neurons in neurodegenerative diseases, including AD and Parkinson’s disease in a preclinical study.

Date Published: 10 March 2015
PDF: 5 pages
Proc. SPIE 9305, Optical Techniques in Neurosurgery, Neurophotonics, and Optogenetics II, 93051Y (10 March 2015); doi: 10.1117/12.2077416

Published in SPIE Proceedings Vol. 9305:
Optical Techniques in Neurosurgery, Neurophotonics, and Optogenetics II
Henry Hirschberg M.D.; E. Duco Jansen; Samarendra K. Mohanty; Nitish V. Thakor; Qingming Luo; Steen J. Madsen, Editor(s)