Speaker
Description
Recent findings in populations exposed to radiation indicate dose-related lens opacification occurs at much lower doses (< 2Gy) than indicated in radiation protection guidelines. As a result, research efforts are now being directed towards identifying early predictors of lens degeneration resulting in cataractogenesis. In this study, Raman microspectroscopy was used to investigate the effects of varying doses of radiation on human lens epithelial (HLE) cells. Samples of live cells adhered to quartz coverslips were irradiated utilizing a 120 kV, 12.5 mA X-ray source at six dose levels, ranging from 0.01 Gy to 5 Gy. The cells were incubated for 24 hours post exposure and then fixed with 10% formalin. Raman spectra were acquired from the nucleus, cytoplasm, and membrane of the chemically fixed HLE cells using a custom-built confocal Raman microscope equipped with a 785 nm laser. For nucleus and cytoplasm targets, spectra were collected from points in a 3x3 grid pattern and then averaged. The raw spectra were background subtracted to remove contribution from the quartz substrate and vector-normalized. Distinct differences between spectra collected from the cytoplasm of the unirradiated HLE cells and those irradiated at 5 Gy were seen after this processing. Principal component analysis and multiclass linear discriminant analysis (PCA-LDA) was used to discriminate by dose. A high classification accuracy (> 95%) was obtained for the leave-one-out classification of cells exposed to 0, 1, 5, 50, and 500 cGy. These initial findings are promising and suggest that Raman spectroscopy may be able to support the early identification of cataract formation.
