Biocompatible Study Of Hydroxyapatite Modified Titanium For Keratoprosthesis In Vivo

ObjectivesTo evaluate biocompatibility of a hydroxyapatite surfaced-modified titanium keratoprosthesis by an acid-alkali chemical treatment after that implanted into the corneal stroma of rabbits.MethodsTwenty-four New Zealand white rabbits were respectively divided into three groups. Surgery operation was performed in right eye of all animals .Skirt of HA-Ti and Ti were respectively inserted into the corneal stroma of experimental group A and group B; only a sack was made without implantation in control group C and the other one was as control. Cornea edema and growth status of new vessels were observed at scheduled times after operation; animals were sacrificed at 2, 4 and 16 weeks after operation and the corneal tissues were evaluated histologically and ultrastructurally.Results1. During the study period, all skirts were stable without infected, dissolved and excluded. Cornea edema and new vessels were revealed after surgery. The new vessels of rabbit eye in group A were more than those in group B. 2. On the 2nd week, the inflammatory response in group A was greater than that in group B (P<0.05).There wasn't significant difference among groups A, B and C after 4 weeks. The number of fibroblasts in group A was markedly increased than that of group B at 2 and 4 weeks (P<0.05). Collagen -III turned into Collagen -I gradually in the extracellular matrix around the skirts.3. PCNA were expressed at all time points in group A, The expression level of PCNA in group A was higher than that in group B (P<0.05) at the 2nd and 4th week, There wasn't significant difference at the 16th week. MMP-2 were absent in the normal corneal matrix. The expression level of MMP-2 in group A was higher than group C at all time points (P<0.05), and was increased than group B at 4th and 16th weeks (P<0.05).4. The extracellular matrix deposited on surface of HA-Ti skirt was more dense and tight.ConclusionHydroxyapatite modified titanium could promote rabbit corneal fibroblast adhension,proliferation and deposited-extracellular matrix in comparison with pure titanium. Hydroxyapatite coationg improve the bioactivity of titanium and promotes the interfacial biointegration of skirt and host cornea. The hydroxyapatite modified titanium by an acid-alkali chemical treatment is a good method for potential use in clinc.