Lab Anim Res.  2016 Dec;32(4):181-186. 10.5625/lar.2016.32.4.181.

Evaluation of stability and biocompatibility of PHEMA-PMMA keratoprosthesis by penetrating keratoplasty in rabbits

• Hwang Y
• Kim G

• KMID: 2362908
• DOI: http://doi.org/10.5625/lar.2016.32.4.181

Abstract

Artificial corneas have been developed as an alternative to natural donor tissue to replace damaged or diseased corneas. This study was conducted to evaluate the stability and biocompatibility of PHEMA-PMMA [poly (2-hydroxyl methacrylate)-poly (methyl methacrylate)] keratoprostheses in rabbits following penetrating keratoplasty. Sixteen male New Zealand White rabbits aged 16 weeks were divided into three groups. Group I and group II contained six rabbits each, while the control group had four rabbits. Experimental surgery was conducted under general anesthesia. The cornea was penetrated using an 8 mm diameter biopsy punch. In group I (core 5 mm & skirt 3 mm) and group II (core 6 mm & skirt 2 mm), the keratoprosthesis was placed into the recipient full thickness bed and sutured into position with double-layer continuous. In the control group, corneal transplantation using normal allogenic corneal tissue was performed with the same suture method. After four and eight weeks, keratoprosthesis devices were evaluated by histopathological analysis of gross lesions. Post-operative complications were observed, such as extrusion and infection in experimental groups. Most corneas were maintained in the defect site by double-layer continuous suture materials for 4 weeks and kept good light transmission. However, most artificial cornea were extruded before 8 weeks. Overall, combined PHEMA and PMMA appears to have sufficient advantages for production of artificial corneas because of its optical transparency, flexibility and other mechanical features. However, the stability and biocompatibility were not sufficient to enable application in humans and animals at the present time using penetrating keratoplasty. Further studies are essential to improve the stability and biocompatibility with or without other types of keratoplasty.

Keyword

Keratoprosthesis; cornea; PHEMA-PMMA; rabbit

MeSH Terms

Anesthesia, General
Animals
Biopsy
Cornea
Corneal Transplantation
Humans
Keratoplasty, Penetrating*
Male
Methods
Pliability
Polyhydroxyethyl Methacrylate
Polymethyl Methacrylate
Rabbits*
Sutures
Tissue Donors
Polyhydroxyethyl Methacrylate
Polymethyl Methacrylate

Figure

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  Figure 1 Gross photographs of PHEMA-PMMA artificial cornea (front view). Artificial cornea with a diameter of core is 5 mm, with 0.45 mm thick using in group I.

• 

  Figure 2 Creation of the recipient corneal pocket and keratoprosthesis. A. The eye is proptosed by means of gentle pressure while an 8 mm biopsy punch is used to create corneal pocket. B. Corneal button remove using 360 degree dissection with scissors. C. The devices are placed into the recipient corneal pocket. D. Double-layer continuous suture is performed using 9-0 polyglactin.

• 

  Figure 3 Gross photographs of the group I, II and control group at 8 weeks after implantation. A: Group I, partial extrusion of device is observed. B: Group II, partial extrusion of device is observed. C: Control group, There are no extrusion of implanted allogenic cornea and no stromal melting. A vascularization to the cornea was observed.

• 

  Figure 4 A: Light microscope photographs of an abnormal cornea that has post-operative infection (black arrow head). Hematoxylin and eosin staining (H&E), ×400. B: Light microscope photographs of the experimental group that has partial extrusion of the device. A separation between a skirt and corneal bed is found (black arrow head). H&E, ×100. C: Light microscope photographs of the experimental group that has complete extrusion of the device after 10 days post-operation. Regeneration of the stroma is shown (black arrow), but continuity of the epithelium is observed lost (black arrow head). H&E, ×100. D: Light microscope photographs of the control group. It shows a corneal structure as normal cornea which includes epithelium, stroma, and proliferated endothelium (black arrow). H&E, ×40.

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