The effect of amniotic membrane proteins released by ocular inserts containing self‐healing hydrogels

Abstract

AbstractPurpose: Growth factors found in the amniotic membrane (AM) help accelerate epithelium regeneration in the damaged cornea or conjunctiva. This study compares the effects of hydrogels releasing the AM proteins on the proliferation, migration, and time‐to‐closure (healing) of the conjunctival epithelium.Methods: Proteins extracted from the AM using sonication were incorporated into two hydrogels used as ocular inserts. The tested inserts materials were the self‐healing, dynamic hyaluronic‐acid hydrogel based on gold‐thiolate/disulfide exchange (Hydrogel A) and a physically cross‐linked hydrogel based on a combination between Eudragit S100 and hyaluronic acid with a reinforced matrix by polyvinyl alcohol, polyvinyl pyrrolidone and polyethylene glycol (Hydrogel B). In an in vitro experiment, a scratch was made on the human conjunctival epithelium cells (Chang Conjunctiva, Clone 1‐5c‐4) to mimic an incision wound. The cells were cultured with hydrogels for 48 hours to study the effect of these materials on epithelium repair. The samples were examined using a Zeiss Observer Z1 inverted microscope, and the results were evaluated employing the Image‐J program to obtain the cell migration rate (μm/h).Results: Hydrogel A increased the rate of closure at 22 h (121 ± 19 μm) in comparison with Hydrogel B (394 ± 78 μm). After 46 h, the scratches in Hydrogel A and control cultures were completely closed, while the Hydrogel B samples had an unclosed area of 54 ± 4 μm.Conclusions: Both hydrogels promoted wound healing in cultured conjunctival epithelium cells. However, a lower rate of wound closure was observed for Hydrogel B than for Hydrogel A and the control, probably because the speed of cell proliferation was slower in Hydrogel B. The wound‐healing assay showed that the Hydrogel A and B increased cell viability and significantly stimulated cell migration.