Abstract:
We have previously determined that the elastic modulus of the decapsulated porcine lens was approximately 1,200 Pa. To elucidate the origin of this elasticity, we characterized the viscoelastic properties of the lens fiber components.
Fresh porcine lenses were decapsulated, and the lens fibers were homogenized in a loose fitting dounce homogenizer. The lens homogenate was centrifuged to yield a supernatant solution containing crystallins and a pellet containing cell membranes and insoluble cytoskeletal proteins. The lens homogenate, unfractionated crystallins, and cell fraction pellet were characterized for their viscoelastic properties at 37°C utilizing an oscillatory capillary rheometer.
All three samples exhibited viscoelastic properties showing elastic and viscous moduli, along with shear thinning and thixotropy. The three samples demonstrated the following trend in the elastic modulus: cell fraction (∼ 2 Pa·s at low shear rates) > lens homogenate (∼ 0.2 Pa·s at low shear rates) > unfractionated crystallins (∼ 0.002 Pa·s at low shear rates).
The shear moduli of the lens homogenate and its components were significantly lower than that of the whole lens. This implies that the lens architecture may play a major role in the material properties of the lens, providing most of the decapsulated lens’s solid–like properties.