Research Of Hydroxyapatite Modified Titanium By IBAD For Keratoprosthesis

ObjectiveAdopt the Ion beam assisted deposition technique to quickly deposites hydroxyapatite on the support surface made by Titanium of the keratoprosthesi; Adopt the design software OSLO of the optics developed by Lambda Research Corporation of American for the design and creation of the artificial cornea mirror pillar.To evaluate the histocompatibility of Titanium frame of the keratoprosthesi with surface modification of hydroxyapatite at molecular level and through histopathology.To observe the histopathological change of artificial cornea inside the body of the animal body.Method1.Pure titanium with three loop-support was used as a substrate after machining into disk.The substrate surface was deposited with calcium phosphate membrane by ion beam assisted deposition(IBAD) method.Using the design software OSLO to design the artificial cornea mirror pillar made by Polymethylmecrylate(PMMA) which was produed by the professional technical persons on the Switzerland instrument lathe.2.A total of 80 SD rabbits were respectively divided into two groups.Skirt of HA-Ti was inserted into the right corneal stroma of rabbits of experimental group as compared with control group which did not insert skirt.Slit lamp was used to observe the corneal edema and neovascularisation.On the 1d,7ds,14ds, 21 ds,28ds,90ds after surgery,histological materials were examined under light microscopy by HE dyeing,specialdyeing,immunohistochemistry dyeing and inspection with electro-microscopy and RT-PCR in order to know the inflammatory reaction,tissue repairment and expressing of relative factors during tissue healing process.3.Twenty New Zealand white rabbits with cornea alkalis burn were random divided into 2 groups after the corneal transplanted with HA-Ti artificial cornea support(include conjunction wreath) for 3 months.After cutting off the central whole layer cornea of support,artificial cornea mirror pillar was inserted in group A.Acellular dermal matrix was put on the rabbits' corneal surface in group B. On the 7ds,28ds,90ds after surgery,the inflammatory reaction of anterchamper was inspected while HE dyeing and immunofluorescence dyeing were performed.Result1.By X-ray diffractometer and energy dispersive spectroscopy,we found the increase of Ca content and Ca/P ratio after adding extra CaO in the HA. Likewise,the Ca/P ratio in the depositing membrane and the combination of Hi membrane with Kpro support base were also increased.Cooperated with professional technicians,we produed artificial cornea mirror pillar of 3mm in diameter and 3.5 mm in length by PMMA using optic design software.2.The matched control SD rats all appears the corneal stimulating symptom after surgery in different degree,new-born blood vessels appeared on the 7d.HE dyeing also showed neovasticulization appeared on the 7d,and decreased on the 14d.On the 28d,the epithelial layer of cornea lightly incrassation with irregular matrix fiber and indistinct vascularizatio and inflammatory reaction.The experimental SD rats were also appears the corneal stimulating symptom after surgery,new-born blood vessels distinctly increased on the 7 ds and stabilized on 21d with no Kpro exclusion.HE dyeing showed neovasticulization appeared on the 7d,and increased more on the 14d.On the 28d,the Kpro was surrounded by the fibrogranulomous tissue.Greenâ…¢-type collagen fibers were also found on the 28d.As to immunohistochemitry,positive expressiong of MMP-9 appeared on the 7d and bFGF on the 28d.Electromicroscopy showed tightly attachment of extra-matrix and corneal cell with HA-Ti frame.RT-PCR found RNA level went up earlier than that of the experiment group.3.The New Zealand white rabbits appeared severely earlier inflammatory reaction after cornea alkali buming which mitigated on the 7d and new vascularization increased.During the observing period,Kpro frame kept stabile without cornea ulcer,putrescence and frame emersion.The cornea edema completely fadeaway after 28d.Compared to the group A,the group B appeared apparent stimulous symptom and better healing of PMMA artificial conea mirror pillar with surrounding comea tissue on the 28d.Also,they had no cornea dissolution.According to the research of Aqueous humor,no distinct change of electrolyte(Na,K,Cl),protein,glucose,and alkalescence between the two groups and normal New Zealand white rabbits.Conclusion1.The PMMA coats deposited on the Ti frame was produed by IBAD method and have much characteristics:high Ca/P ratio,strong conglutination and easily preparation for artificial cornea.2.The HA-Ti frame made by IBAD was confirmed by animal experiment that its surface was attached with a fiberous vascular tissues and healed better with host cornea.3.The artificial cornea of this topic can stable exist over a long period of time in the rabbit cornea.The decrease of complications depends on the improvement of the mirror pillar creation craft.