Implantation of hydroxyapatite-titanium corneal implants in rat cornea.
OBJECTIVE
To evaluate the biocompatibility of hydroxyapatite-coated titanium (HA/Ti) corneal implants at the molecular levels with histopathology.


METHODS
Eighty Sprague-Dawley rats were divided into 2 equal groups. In the study group, HA/Ti prosthetics were implanted into the right corneal stroma. The control group received a sham incision. Corneas were collected and studied with histopathological examination (HE), immunohistochemical, and other stains, including scanned electron microscopy and reverse transcription-polymerase chain reaction, to evaluate inflammatory reactions, tissue repair, and expression of various biological factors during healing.


RESULTS
In the control group, corneal neovascularization occurred 7 days after surgery, and the corneas recovered 28 days after surgery. In the study group, corneal vascularization increased substantially on day 7 and stabilized on day 28. For both groups, reverse transcription-polymerase chain reaction detected expressions of 6 primers at all time points. The amplified sequences were consistent with the designed sequences. The expression of matrix metalloproteinase-2, matrix metalloproteinase-9, bFGF, vascular endothelial growth factor, and type III collagen were delayed in the study group compared with the control group. Histological analyses showed a tight attachment of the corneal tissue to the HA/Ti implant on day 28.


CONCLUSIONS
The HA/Ti corneal implants can remain stable in corneal tissue for a long time, induce corneal neovascularization, and stimulate inflammatory cells and keratocytes to synthesize or activate matrix metalloproteinases. Artificial cornea made from this material show enhanced stability and biocompatibility in vivo.
Fang
Yin Dong
YD
Department of Surgery, Division of Ophthalmology, Chinese PLA (People's Liberation Army) General Hospital, Postgraduate Medical School, Beijing, China.
Xiao
Ma
M
Fei
Huang Yi
HY
D000818:Animals; D020099:Coated Materials, Biocompatible; D024061:Collagen Type III / Q000378:metabolism; D016510:Corneal Neovascularization / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D003319:Corneal Stroma / Q000378:metabolism / Q000601:surgery* / Q000648:ultrastructure; D017886:Durapatite; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D008297:Male; D008422:Materials Testing; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014025:Titanium; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014945:Wound Healing
D020099:Coated Materials, Biocompatible; D024061:Collagen Type III; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D016222:Fibroblast Growth Factor 2; D017886:Durapatite; D014025:Titanium; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9