title: [The expression level of MMP-2 and collagen of hydroxyapatite modified titanium for keratoprosthesis in the corneal stroma of rabbits].
abstract: OBJECTIVE
  To investigate the expression level of metalloproteinases-2(MMP-2) and Collagen in a hydroxyapatite surfaced-modified of three Pan type titanium keratoprosthesis after that implanted into the corneal stroma of rabbits, further evaluate its biological compatibility.
  
  
  METHODS
  Experimental study. Twenty-four New Zealand white rabbits, 2.0-2.5 kg, were respectively divided into three groups. Surgery was performed in right eye of all animals. skirt of HA-Ti and Ti were respectively inserted into the corneal stroma of rabbit of experimental group A and group B; only a sack was made without implantation in control group C . Cornea edema and corneal neovascularization were observed at scheduled times after operation; animals were sacrificed 2, 4 and 16 weeks after operation and their cornea was removed and examined under light microscopy; the surface of skirt was observed under scanning electron microscope.
  
  
  RESULTS
  During the study period, all skirts were stable without infected, dissolved and excluded. Different degree of cornea edema and neovascularization was revealed after surgery. 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 (F = 6.083, P < 0.05), and was increased than group B at 4th (F = 47.074, P < 0.01), and was increased than group C at 16th weeks too (F = 6.079, P < 0.05) . Corneal organization has a large green 4 weeks type III collagen and yellow red type I collagen, 16 weeks corneal mainly for bright red when within the collagen type I, still have a small amount of collagen type III.
  
  
  CONCLUSIONS
  Rabbit cornea implanted HA-Ti skirts cause MMP-2 activation, continuous high expression didn't cause the cornea to dissolve; Collagen -III turned into collagen-I gradually in the extracellular matrix around the skirts. Hydroxyapatite modified titanium for Keratoprosthesis promoted the corneal neovascularization and improve the interfacial bio integration of skirt and host cornea.
authors.affiliation: Department of Ophthalmology, PLA General Hospital, Beijing 100853, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Gai-ping
authors.initials: GP
authors.lastname: Du
authors.forename: Li-qiang
authors.initials: LQ
authors.lastname: Wang
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Wang
authors.forename: Fu-zhai
authors.initials: FZ
authors.lastname: Cui
authors.forename: Yu-jie
authors.initials: YJ
authors.lastname: Lu
authors.affiliation: Email:301yk@sina.com.
authors.forename: Yi-fei
authors.initials: YF
authors.lastname: Huang
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000378:metabolism*; D017886:Durapatite / Q000737:chemistry*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D019736:Prostheses and Implants; D011817:Rabbits; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D003094:Collagen; D017886:Durapatite; D014025:Titanium; D020778:Matrix Metalloproteinase 2