A study of fluorescence spectra of peripheral arteries: intrinsic fluorophore emission in the intima under hypodynamic stress

Abstract

We have examined the effects of hypodynamic stress (as one of the risk factors for cardiovascular disease) on the central ear arteries on rabbits and associated arterial injury. A 48-day hypodynamic stress was provoked in Chinchilla male rabbits by confining them to a confined space with a limite potential for movement. The intima of the central ear arteries was examined by autofluorescence and electron microscopy. Laser-induced fluorescence was examined during excitation at a range of wavelengths 320–360 mm at the absorption maxima of several fluorescing connective tissue proteins. Changes in fluorescence profiles of an intact artery and an artery affected by hypodynamic stress were detected in the spectral range from 370 to 550 nm. Spectroscopic examination revealed a decreased relative fluorescence intensity at around 410 nm and red-shifted fluorescence emission for affected artery wall in comparison with intact artery intima. Ultrastructural studies indicated that the internal elastic lamina and subendothelial layer were disintegrated or lessening, and cholesterol had accumulated in the inner wall of central ear arteries in stress-affected rabbits. Initial results show that structural chantes of the central ear artery intima due to hypodynamic stress can be monitored using fluorescence spectroscopy. Keywords: autofluorescence, artery, ultrastructure, hypodynamics