Physical Properties of Pig Vitreous Body

Microscope laser light scattering spectroscopy is applied to investigate the structural and dynamical properties of the gel network in the pig vitreous body. It is natural to consider the collagen motion is coupled with the dynamics of Na-hyaluronate; therefore, we develop the equation for the mode coupling of flexible Na-hyaluronate and semirigid network of collagen. The unique physical properties of a gel arise from its structure. The gel is characterized by two kinds of bulk coefficients: (1) the elastic constants of the gel network and (2) the friction coefficients between gel network and the fluid. We determine the friction coefficients between vitreous gel network and gel fluid using a specially designed apparatus. Together with experimental and theoretical results, the dynamics of collagen and Na-hyaluronate explains two relaxation modes of the fluctuation. The diffusion coefficient of collagen obtained from Dfast and Dslow is very close to that in aqueous solution, which suggests the vitreous body is in the swollen state. The diffusion coefficients were found to be dependent on the position (surface or central part) of the vitreous body from which the scattered light sampled. The inhomogeneous distribution of Na-hyaluronate and collagen and the shell structure of the vitreous body were suggested.