Abstract
Purpose :
To measure in vivo the action spectrum of intrinsic fluorophores in the living mouse retina and use this knowledge to derive information about biochemical components responsible for the autofluorescence spectra.
Methods :
We have upgraded a previously characterized mouse retinal Scanning Laser Ophthalmoscopy / Optical Coherence Tomography (SLO/OCT) system with a super continuum light source (SuperK EXTREME EXU-6) and a SuperK VARIA tunable wavelength filter. This system allows delivery of light controlled in wavelength and intensity for excitation of fluorescence. The fluorescence emission spectrum of selected retinal regions of interest is measured with an Ocean Optics spectrometer.
Results :
Autofluorescence action spectra were measured for Balb/c and C57Bl/6J mice using 12 distinct excitation wavelengths ranging from 440 nm to 560 nm with fluorescence emission monitored between 570nm and 800nm range. An example action spectrum measured in Balb/c mice is shown in the figure below. The shape of this spectrum resembles the absorption spectrumof A2E (see figure below).
Conclusions :
We have developed a system capable of in vivo measurement of the action spectrum of fluorophores in the living mouse retina. Availability of action spectra together with emission spectrum for autofluorescence will be helpful for distinguish specific chemical mechanisms responsible for the fluorescence signals, for example in different mouse models of retina degeneration, and also for “unmixing” the signals from endogenous and exogenous fluorochromes.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.