Effect of substance P, insulin-like growth factor-1 and vasoactive intestinal polypeptide on corneal re-epithelialization in galactosemic rats.
OBJECTIVE
The purpose of the study was to examine the effect of topical application of substance P (SP), insulin-like growth factor-1 (IGF-1) and vasoactive intestinal polypeptide (VIP) on corneal re-epithelialization in galactosemic rats.


METHODS
Experimental galactosemia was induced by feeding a diet containing 30% galactose for 4-6 months. The corneal epithelium was debrided bi-laterally by scraping with a blunted scalpel blade. One eye (control) received only a saline solution whilst the other eye received a solution of SP and/or IGF-1 or VIP. A single drop of control or test solution was administered 4 times daily until wound closure. Corneas were stained with fluorescein and videotaped under ultraviolet illumination at regular time intervals after debridement. After digitizing the video image, the wound area was calculated using an image analysis program (NIH Image).


RESULTS
Corneal re-epithelialization was significantly delayed in galactosemic compared to normal animals. Rates of healing were 1.3 +/- 0.07 mm2/hour and 1.02 +/- 0.02 mm2/hour for normal and galactosemic animals, respectively. Topical application of SP in concentrations ranging from 25 pg/ml up to 250 microg/ml had no significant effect on the rate of corneal re-epithelialization. Similarly, IGF-1 (1 microg/ml) or VIP (1 microg/ml) when applied alone did not affect re-epithelialization. Furthermore, resurfacing of the debrided area was not affected by co-application of SP (250 microg/ml) and IGF-1 or VIP.


CONCLUSIONS
Independent or combined topical application of SP, VIP or IGF-1 at the concentrations tested, does not modulate corneal epithelial wound healing in rats with galactosemia induced by 30% galactose.
McDermott
A M
AM
Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison 53706, USA.
Kern
T S
TS
Reid
T W
TW
Russell
P
P
Murphy
C J
CJ
D000818:Animals; D003315:Cornea / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D003646:Debridement; D004359:Drug Therapy, Combination; D004848:Epithelium / Q000293:injuries / Q000502:physiology; D005690:Galactose; D005693:Galactosemias / Q000139:chemically induced / Q000503:physiopathology*; D007091:Image Processing, Computer-Assisted; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009883:Ophthalmic Solutions; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000187:drug effects / Q000502:physiology*; D013373:Substance P / Q000008:administration & dosage / Q000494:pharmacology*; D014660:Vasoactive Intestinal Peptide / Q000008:administration & dosage / Q000494:pharmacology*; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology*
D009883:Ophthalmic Solutions; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D007334:Insulin-Like Growth Factor I; D005690:Galactose