Biocompatibility Of Chitin Carrier And Its Effect On Wound Healing Of Corneal Epithelium

Purpose：The cornea is the eye’s outermost lens, which plays a very important role inmaintaining the vision. Cornea functions like a barrier and its structure is relativetough. The damages of corneal epithelium have much influence on normal lives. Whatis worse, corneal epithelium cannot regenerate when corneal limbal stem cells isdamaged. So it is necessary to choose an appropriate and effective method toreconstruct corneal epithelium. At present, tissue engineering is a common way toreconstruct corneal epithelium. However, the application of corneal carrier scaffold islimited by flexibility, degradation rate and immunological rejection of the material. Sochoose a safe, nontoxic, flexible material, which possesses appropriate decreased rate,lower immunological rejection and easy accessibility is becoming a hotspot in thefield of cornea carrier scaffold material research. Chitin has delivered biologicalpotential for a wide range of biological medicine, as it has many advantages such asanti-inflammatory and antioxidant activities, antimicrobial effects,immunity-enhancing as well as antitumor effects and drug delivery.Methods:1. The main material of present study is chitin, the following aspects wereresearched: Properties of chitin, preparation of chitin-based membrane and itsphysicochemical property: Molecular weight, deacetylation degree, structure byinfra-red spectrum and some other physicochemical properties were measured. Togenerate chitin colloidal solution, chitin and chondroitin sulfate were dissolved inmethanoic acid to prepare blended membranes. The thickness, moisture content,luminousness, mechanical properties and other physicochemical properties weremeasured.2. The biocompatibility of chitin-based membrane: The blended membranes withcurvature were attached to the eyeball surface of New Zealand White Rabbit. Observation on the rabbit eyeball reaction was conducted at regular time toinvestigate the stimulus-response of chitin-based membranes to eyes. Cytotoxicity ofchitin-based membranes was assessed by MTT method. Development and attachmentstatus of chitin-based membranes were observed with scanning electron microscope.Membranes were transplanted in the SD rat subcutaneous tissues and leg muscles toobserve their degradability and tissue compatibility in vivo.3. The repair capacity of chitin-based membranes with cells to corneal epitheliumdamage: Chitin-based membranes with cells were transplanted to surface of damagedrabbit cornea epithelium. Fluorescence staining was conducted at regular time toobserve their repair status. The repaired cornea epithelium was analyzedpathologically and observed with scanning electron microscope.Results:1. The material used in the present study was large molecular weight chitin withrelatively low deacetylation degree, its deacetylation degree is19.33%and molecularweight is2×106KD. A proper method to prepare chitin-based membranes andmembranes with curvature were established. The thickness of chitin-basedmemebrane was0.2mm.The water content of chitin-based membranes was81.59%.The transparencies on different wavelength were greater than80%, the tensilestrength on dry state and wet state were14.925MPa and3.28MPa.2. No stimulation or cytotoxic reaction was observed on chitin-based membrane.Besides, the blend membrane possessed good cytocompatibility and could promotecornea epithelium cell proliferation and growth on the membranes. Its degradationrate is relatively long, its about22weeks in subcutaneous and18weeks in musculartissue. The good tissue compatibility and light inflammatory response, supported thefact that chitin membrane was favorable in biocompatibility.3. It was also demonstrated in this study that chitin-based membranes with cellscould accelerate the cornea epithelium repair rate. The epithelial structure of repairedcornea was observed to be compact and neat.Conclusions:The carrier scaffold materials of cornea prepared with chitin and chondroitin sulfate generally meet the requirements of cornea materials in tissue engineering. Theseresults would lay the foundation of studying corneal carrier scaffold materials.