Studies on corneal wound healing. Effect of fucose on iodine vapor-burnt rabbit corneas.
Corneal wound healing often leads to the development of scar tissue with loss of transparency. Reconstitution of transparent corneal stroma depends on the regulation of the biosynthetic activities of postlesional keratocytes and also to a large extent on the limitation of matrix degradation, attributed essentially to the upregulation of matrix metalloproteases and especially MMP-9. Using a standardized method for the production of reproducible corneal lesions by burning with iodine vapors, we could show that the local application of 0.5 mg/ml L-fucose reduced significantly MMP-9 upregulation and accelerated the recovery of the epithelial layer of the cornea. The iodine vapor used in the experiments produces a rapid loss of epithelium with no or slight effect below the basement membrane. A relatively rapid regrowth of epithelium was observed. The speed of this reepithelialization was stimulated by the local application of fucose. At 48 h after burn, there was a difference between fucose-treated and control corneas (epithelial thickness was about 50 mum for fucose-treated corneas and 37 microm for control corneas). Culture media of in vivo fucose-treated corneas showed an important decrease of MMP-9 activity (-51%, n = 6, p < 0.01). It appears that the in vivo fucose treatment reduced the MMP-9 activity released in the media. This effect is significant 24 h after iodine vapor burn. In order to study the effect of fucose on normal corneas, it was added to rabbit as well as human cornea explant cultures, and the production and release of MMP-9 was determined by zymography. Fucose at a concentration of 0.5 mg/ml produced a 70% decrease of MMP-9 activity released in the medium by corneal explant cultures. Other mono- and oligosaccharides were also tested. Besides lactose, fucose-rich oligosaccharides also produced significant inhibition. Galactose, melibiose, mannose and glucose were inactive. These results justify the use of fucose for the local treatment of corneal wounds.
Isnard
N
N
Laboratoire de Recherche en Ophtalmologie, INSERM CRI 9808, Hôpital Hôtel Dieu, Université Paris 5, France. n.isnard@extracellular-matrix.com
Bourles-Dagonet
F
F
Robert
L
L
Renard
G
G
D000818:Animals; D002057:Burns, Chemical / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D015536:Down-Regulation; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000648:ultrastructure; D005126:Eye Burns / Q000139:chemically induced* / Q000188:drug therapy / Q000201:enzymology; D005643:Fucose / Q000627:therapeutic use*; D007455:Iodine / Q000633:toxicity; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009924:Organ Culture Techniques; D011817:Rabbits; D014945:Wound Healing / Q000187:drug effects*
D005643:Fucose; D007455:Iodine; D020780:Matrix Metalloproteinase 9