Abstract
Purpose
To investigate the effects of an amniotic membrane patch on corneal epithelial thickness and formation of hemidesmosomes during corneal stromal wound healing.
Methods
A stromal wound 9 mm in diameter and 130 μm in depth was created on rabbit cornea using a microkeratome. The changes in corneal epithelial thickness and hemidesmosome formations were compared between the amniotic membrane, contact lens, and control groups. Changes in the corneal epithelium were examined using H&E staining and hemidesmosome formation was examined using an electron microscope at 2 and 4 weeks after flap removal.
Results
Two weeks after treatment, the corneal epithelial thickness was 95.3 ± 6.3 μm in the amniotic membrane group being significantly thicker than 76.4 ± 5.1 μm in the contact lens group and 68.3 ± 6.1 μm in the control group. Furthermore, more hemidesmosome formations were observed in the amniotic membrane group compared to the other 2 groups. However, there were no significant differences in corneal epithelial thickness or hemidesmosome formation among the 3 groups at week 4.
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![]() | Figure 1.Photographs showing the making and removal of the corneal wound (diameter 9 mm, depth 130 μm). (A) Creating the corneal wound flap with Microkeratome (BDK3000, Becton & Dickinson, Franklin Lakes, NJ, USA). (B) Corneal flap. (C) Lifting of the corneal wound flap and cutting the hinge of the corneal flap using a blade. (D) Fluorescein dye staining after corneal flap removal. |
![]() | Figure 2.Photograph of the rabbit cornea after amniotic membrane patch graft. Arrowheads indicate the original amniotic membrane patch margin (diameter 14 mm) and arrows indicate 10-0 nylon sutures. |
![]() | Figure 3.Light microscopy of the central cornea at 2 weeks. (A) Normal cornea. (B) Amniotic membrane group. (C) Contact lens group. (D) Control group. Corneal epithelial thickness in the amniotic membrane group is thicker than the other groups (Hematoxylin-Eosin stain, original magnification ×100). |
![]() | Figure 4.Light microscopy of central cornea at 4 weeks. (A) Normal cornea. (B) Amniotic membrane group. (C) Contact lens group. (D) Control group. Corneal epithelial thickness is similar in all groups (Hematoxylin-Eosin stain, original magnification ×100). |
![]() | Figure 5.Comparison of central corneal epithelial thickness among the 3 groups at 2 weeks and 4 weeks. In all groups, the central corneal epithelial thickness was significantly thicker at 2 weeks than at 4 weeks. * Corneal epithelial thickness in the AM group is significantly thicker than the CL and control group at 2 weeks. † Corneal epithelial thickness in the CL group is significantly thicker than the control group. AM = amniotic membrane; CL = contact lens. |
![]() | Figure 6.Transmission electron photomicrographs (original magnification ×45,000) of the central cornea at 2 weeks. (A) Morphologically established hemidesmosome is found in the amniotic membrane group. (B) Morphologically identifiable hemidesmosomes appear in the contact lens group. (C) Hyperactive formation of adhesion complex in the control group. |
![]() | Figure 7.Transmission electron photomicrographs (original magnification ×45,000) of the central cornea at 4 weeks. (A) Amniotic membrane group. (B) Contact lens group. (C) Control group. Morphologically established hemidesmosomes (arrowheads) are detected in all groups. There are no significant differences in adhesion complex formation among the 3 groups. |
Table 1.
The comparison of corneal epithelial thickness among the 3 groups 2 mm from the limbus (Corneal flap did not involve this area)
Groups | n | Epithelial thickness (mean ± SD, μm) | p-value* |
---|---|---|---|
Control group | 9 | 51.4 ± 4.3 | |
AM group† | 9 | 50.3 ± 3.3 | 0.73 |
CL group‡ | 8 | 52.6 ± 3.3 |
Table 2.
The comparison of the central corneal epithelial thickness among the 3 groups
Time | Control group (mean ± SD, n = 8) | AM group*(mean ± SD, n = 9) | CL group†(mean ± SD, n = 9) | p-value‡ |
---|---|---|---|---|
2 weeks | 68.3 ± 6.1 | 95.3 ± 6.3 | 76.4 ± 5.1 | 0.012 |
4 weeks | 51.4 ± 4.7 | 50.0 ± 6.5 | 51.8 ± 3.9 | 0.612 |