Effect on rabbits’ intraocular structure by cross-linked hyaluronic formations as vitreous substitute

Purpose: To observe the effects of cross-linked hyaluronic hydrogel on retina struct and intraocular biocompatibility in rabbits. Methods: the polymer-derived hyaluronic acid which was formed by UV light cross-linked with N-vinyl-pyrrolidone. Free hyaluronic acid levels were detected by spectrophotometric method. Vitrectomy was then performed in the rabbits, and then cross-linked hyaluronic acid hydrogels of different concentrations were injected. Intraocular pressure measurements, cornea check-up, and B-ultrasound examination were performed during the follow-up period. After six weeks’ follow-up, the rabbits were sacrificed, and both eyes were removed. The eyeballs were fixed for HE staining, and the polymer materials were observed under electron microscopy. Results: The synthetic hydrogel present a transparent substance with a refractive index similar to that of the human vitreous body, which also had sufficient viscosity and elasticity for intraocular usage by rheological measurements. The results of the free hyaluronic acid test showed that the hydrogel had little degrade within one month. The results of the histology, intraocular pressure, B-ultrasound and retinal ultrastructure suggested that cross-linked hyaluronic acid hydrogel had superior tissue biocompatibility intraocular for six weeks. Conclusions: Hyaluronic acid-based cross-linked biopolymers had good biocompatibility in rabbit, which also shown promising potential as vitreous substitutes in clinical practice.