PURPOSE To explore the therapeutic role of a novel polysaccharide hydrogel composed of plant polysaccharides and L-lysine-cross-linker on the corneal trauma healing.
METHODS Polysaccharides were extracted from a chinese herb plant and thioesterified. The composition of plant extract was determined by infrared spectrum ananlysis . To establish corneal wound animal model, anterior lamellar keratoplasty was carried out with Sprague-Dawley (SD) rats using 4mm trephine. Animals were randomly divided into two groups. With experimental group, poly L-lysine-cross-linker and thioesterified polysaccharide solutions were applied onto the lamellar bed seqentially to form hydrogel membrane within 10 senconds. Amniotic membrane was covered on top of polysaccharide hydrogel and sutured to conjunctiva. With control group, amniotic membrane alone was sutured to conjunctiva to mantle the entire corneal surface. At 3, 7, 14 ,60 days post-surgery, corneal transparency ,corneal neovascularization and corneal epithelial defect size were examined with slit lamp microscopy and fluorescein staining. Measurement and calculation were carried out using photoshop image processing software, and data statistically analyzed. At each time point, The rats were sacrificed and the eyes removed for histological studies to examine regeneration and structure of corneal epithelium and stroma.
RESULTS Infrared spectrum ananlysis determined that the hydrogel was mainly composed of mannan、β-D-glucopyranoside and β-D-diglucoside. Compared to the control group, corneas in experimental group showed clearer apperance, less neovascularization and smaller corneal defect area at each time point after surgery. Histology examination revealed that experimental group had thicker epithelium, less inflammatory infiltration, milder corneal edema and more ordered stroma structure in comparison with control group.
CONCLUSIONS With extract of chinese herb, we created a novel polysaccharide hydrogel mainly composed of mannan、β-D-glucopyranoside and β-D-diglucoside. By cross-linking with poly L-lysine, polysaccharide hydrogel membrane can be readily formed on the surface of lamellar bed of anterior lamellar keratoplasty cornea. Post-surgery examinations demonstrated that our polysaccharide hydrogel significantly promoted the healing of the corneal epithelium and stroma wound. Our study proved treatment with chinese herb derived polysaccharide hydrogel a potent therapy for corneal trauma healing , and is promising for future clinical applications. |
