Recognition of by laser-induced fluorescence spectroscopy ex vivo structural changes of thoracic aorta intima IN rabbits subjected to hypodynamic stress

Anotacija

The investigation was performed to evaluate the possibilities of fluorescence spectroscopy in recognising structural changes of the thoracic aorta intima in rabbits subjected to hypodynamics (as a risk factor for cardiovascular disease). A 48-day hypodynamic stress was provoked in Chinchilla male rabbits (n = 8) by placing them in metal hutches. The control (n = 8) rabbits had no intervention and were kept under normal vivarium conditions. The ultrastructure of thoracic aorta intima samples (of each control and each subjected to hypodynamics rabbits) was evaluated by electron microscopy (Philips-300). Also, fluorescence spectra characteristics of each control aorta intima and each aorta intima affected by hypodynamic stress at varying excitation wavelengths (340– 415 nm) were recorded by picosecond Nd laser spectroscopy in the spectral range of 375–675 nm. An increase in the intensity of fluorescence emission in the stressed aorta intima at a wavelength close to 570 nm (excitation 345–365 nm) and a lowered fluorescence emission intensity at around 445 nm (excitation 350–365 nm) were determined in comparison with the control aorta intima (P < 0.05). Fluorescence excitation-emission matrices also showed a more intense fluorescence for the control aorta intima at a wavelength of around 445 nm, while expressive fluorescence was shown by the stressed aorta at longer wavelenghts (around 570 nm). At the same time, cholesterol was accumulated in the inner wall of the thoracic aorta, the elastica interna and the subendothelial layer were disintegrated in stress-affected rabbits. Initial results of laser fluorescence spectroscopy promise the possibility of discriminating between normal and abnormal aorta intima based on ultrastructural alterations caused by hypodynamic stress. Keywords: fluorescence, hypodynamic stress, thoracic aorta, ultrastructure