In vitro evaluation of the effect of tobacco smoke on rat cornea function

The influence of tobacco smoke on the dielectric properties of rat cornea were measured in vitro over the frequency range of the electric field of 500Hz-100kHz and in temperatures of the air from 25 to 150 degrees C. The temperature dependencies of the loss tangent for both healthy and smoky cornea represent the relation between the energy lost and the energy stored in the epithelium-stromal-endothelium systems of the cornea. The differences between the healthy and the smoky cornea concerned the temperature ranges in which there appeared the decomposition of loosely-bound water and beta-relaxation associated with polar side-chains relaxations on protein molecules of this tissue. The effect of smoke is manifested as a shift of the loss tangent peaks of these two processes towards higher temperatures, when compared with the control. The results are interpreted as caused by the toxic compounds of the tobacco smoke leading to higher ion transport in the nonhomogeneous structure of the cornea when compared to that of the control tissue. The activation energy of conductivity were similar for the healthy and smoky cornea as a consequence of the braking of hydrogen and Van der Waals bonds between loosely bound water, and the proteins of channels in the epithelium and endothelium. Recognition of the effect of frequency and temperature on the dielectric behaviour of the smoky cornea may be of interest for disease characterization of this tissue.