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Repair of Corneal
Wounds in vivo by Photochemical Tissue Bonding
Proano, Cinthia 1,2,
Jones, Erika 1, Mulroy, Louise 1,
Azar, Dimitri 1,2, Kochevar, Irene 1
and Redmond, Robert1
Wellman Laboratories of Photomedicine, Department of Dermatology, Harvard
Medical School, Massachusetts General Hospital, W-224, Boston, MA 021141
Cornea and Refractive Services, Harvard Medical School, Massachusetts
Eye and Ear Infirmary, Boston, MA 021142
Abstract-
Traditional methods of wound closure, such as suturing, are not suited
to all tissues and have drawbacks associated with foreign body response
and infection. The ideal closure method would be rapid, non-invasive
and yield a strong water-tight seal, while retaining structural integrity.
The latter is particularly important in the cornea where any deformation
will induce astigmatism and visual impairment. Dye-assisted photochemical
tissue bonding provides an intriguing alternative whereby collagen crosslinking
is induced between apposed wound surfaces. We report feasibility studies
to repair 3.5 mm incisional wounds in the cornea of New Zealand white
rabbits using this approach. Wound surfaces were coated with a 1.5 mM
solution of rose bengal and illuminated with 514 nm laser light. The
strength of wound closure was determined by measuring the intraocular
pressure (IOP) required to rupture the closed wound. Dose response studies
showed increasing closure strength with treatment time. A dose of ~150
J/cm2, delivered at 500 mW/cm2, produced wound closure that routinely
withstood IOPs of ~500 mm Hg, far higher than the normal IOP of ~25
mm Hg. The treatment proved to be far more efficient in vivo than previously
found ex vivo in the same model. Follow-up studies showed that this
strength was retained for weeks after treatment. Wound healing was also
followed over a period of weeks. Initial inflammation and corneal haziness
were apparent for up to two weeks post-treatment but had resolved by
four weeks. Preliminary studies also showed feasibility for attachment
of corneal transplants to host cornea in the same animal model. This
study underlines the potential of photochemical tissue bonding as an
alternative to mechanical closure methods for efficient repair of corneal
tissue and other delicate collagenous tissues.
Keywords: tissue
repair, photosensitization, rose bengal, cornea
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