[Corneal burns and matrix metalloproteinases (MMP-2 and -9): the effects of human amniotic membrane transplantation].
OBJECTIVE
Human amniotic membranes have recently been used in ophthalmology to restore deleted ocular surface after burns. Matrix metalloproteinases-2 and -9 have been implicated in the development of neovascularization. In this study, MMP-2 and MMP-9 expression was analyzed by in situ zymography on rabbit corneal chemical burns with and without human amniotic membrane graft.


METHODS
Corneal neovascularization was induced in 10 Fauve de Bourgogne rabbits by means of a heptanol chemical burn on controlled deep keratotomy using a Chiron ALK-E corneal shaper. Half of rabbits received acute amniotic membrane transplantation 30mn after chemical burn; the remaining five rabbits received medical treatment. In situ zymography is a recent nondestructive technique which preserved the fine morphological details of the cornea and showed the active enzyme location in different corneal layers. The MMP-2 and -9 substrate was gelatin, which was detected by fluorescent microscopy.


RESULTS
There was an overexpression of MMP-2 and -9 in corneal burns versus control corneas. Expression of MMP-2 and -9 was low in corneal burn without amniotic membrane graft. Following amniotic membrane transplantation, MMP-2 and -9 were strongly expressed and clinical neovascularization and inflammation decreased. Active enzymes were located in epithelium layers in the uncovered group. In the covered group, the active enzymes were located in the anterior and posterior stromal layers.


CONCLUSIONS
The results support a role for MMP-2 and MMP-9 in corneal burn neovascularization. Amniotic membrane transplantation can play a protective role by up-regulation of their biological expression.
Rigal-Sastourné
J C
JC
Service d'Ophtalmologie, HIA Val de Grâce, 74, boulevard de Port-royal, 75230 Paris Cedex 05, France.
Tixier
J M
JM
Renard
J P
JP
Maurin
J F
JF
Pouliquen
Y
Y
Legeais
J M
JM
D000650:Amnion / Q000637:transplantation*; D000818:Animals; D002057:Burns, Chemical; D017364:Collagenases / Q000378:metabolism; D003315:Cornea / Q000098:blood supply*; D004195:Disease Models, Animal; D005126:Eye Burns / Q000201:enzymology* / Q000601:surgery*; D018093:Gelatinases / Q000378:metabolism; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D011817:Rabbits; D014183:Transplantation, Heterologous
D017364:Collagenases; D018093:Gelatinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9