Messenger RNA levels for genes involved in extracellular matrix from human corneal scrapings before and after photorefractive keratectomy.
OBJECTIVE
To measure the levels of mRNA for genes important in cellular and extracellular matrix regulation in human corneal epithelium before and after photorefractive keratectomy (PRK) in order to explain myopic regression following surgery.


METHODS
Scrapings from 26 normal corneas before a first photorefractive keratectomy were randomly pooled in two samples of 16 and 10 scraping, respectively, and compared to another 23 scrapings from corneas with myopic regression after a previous photorefractive keratectomy, also randomly pooled in another 2 samples of 16 and 7 scrapings each. The scrapings were analysed for seven different messenger RNAs involved in extracellular matrix using competition-based quantitative reverse-transcription polymerase chain reaction.


RESULTS
Messenger RNAs for TGFalpha (Transforming growth factor-alpha), TGFbeta1 (Transforming growth factor-beta1), EGF-R (Epidermal growth factor-receptor) and TIMP1 (Tissue inhibitor metalloproteinase-1) were present in all samples. No mRNA for MMP9 (Metalloproteinase 9) or MMP2 (Metalloproteinase 2) were detected in any sample. Messenger RNA for collagen (alpha1) III was present in one sample following photorefractive keratectomy.


CONCLUSIONS
The detection and measurement of levels of messenger RNA for selected growth factors, receptors, metalloproteinases and extracellular matrix proteins in ex vivo samples of human corneal epithelium is important and possible with a modified polymerase chain reaction technique. Messenger RNAs for Collagen III and for TGF-beta1 were elevated in one sample after photorefractive keratectomy.
Tomas-Barberan
S
S
St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden.
Schultz
G S
GS
Tarnuzzer
R W
RW
Fagerholm
P
P
D000328:Adult; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D019573:Epithelium, Corneal / Q000378:metabolism* / Q000601:surgery; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005109:Extracellular Matrix / Q000235:genetics* / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006133:Growth Substances / Q000235:genetics / Q000378:metabolism; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000378:metabolism* / Q000601:surgery; D018903:Photorefractive Keratectomy; D010865:Pilot Projects; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics / Q000378:metabolism
D005136:Eye Proteins; D006133:Growth Substances; D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; D003094:Collagen; D066246:ErbB Receptors