Immunohistochemical observation of amniotic membrane patching on a corneal alkali burn in vivo.
OBJECTIVE
To investigate by immunohistochemical observation the effects of amniotic membrane (AM) patching on myofibroblastic differentiation and matrix metalloproteinase (MMP) expression in the corneal stroma after an alkali burn in vivo.


METHODS
A corneal alkali burn was made by placing a circular piece of filter paper containing 1 N NaOH on the central cornea of rabbits. Burning was done unilaterally in each rabbit. Immediately after the wounding, in the AM group, AM was sutured onto the cornea and removed on day 1. Rabbits with no AM patching were controls. On day 14, corneas were excised and immunohistochemical observation was carried out using antibodies against alpha-smooth muscle actin (alpha-SMA), vimentin, MMP-1, MMP-2, MMP-9, and membrane-type1 (MT1)-MMP. Observation after Masson trichrome staining was also performed.


RESULTS
In the AM group, alpha-SMA positive cells were noticeably fewer, and MMP-2, MMP-9, and MT1-MMP expression was clearly inhibited. Also, collagen fibers were more regularly arranged than in control eyes. The more proximate the cells were to the epithelial side, the fewer alpha-SMA-positive cells were observed in the AM group.


CONCLUSIONS
AM patching suppressed myofibroblastic differentiation and MMP expression in the stroma after an alkali burn. An inhibition gradient suggests that AM may release unknown soluble factors possessing some antiscarring capability.
Takahashi
Hiroshi
H
Department of Ophthalmology, Nippon Medical School, Tokyo, Japan. tash@nms.ac.jp
Igarashi
Tsutomu
T
Fujimoto
Chiaki
C
Ozaki
Noriko
N
Ishizaki
Masamichi
M
D000199:Actins / Q000378:metabolism; D000650:Amnion / Q000637:transplantation*; D000818:Animals; D002057:Burns, Chemical / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D002454:Cell Differentiation; D003316:Corneal Diseases / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D003319:Corneal Stroma / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005126:Eye Burns / Q000139:chemically induced*; D005260:Female; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D053511:Matrix Metalloproteinase 14; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D011817:Rabbits; D012972:Sodium Hydroxide
D000199:Actins; D012972:Sodium Hydroxide; D020782:Matrix Metalloproteinases; D053511:Matrix Metalloproteinase 14