Transforming growth factor-beta expression in rat eyes with mechanical debridement of corneal epithelium or epithelial flap.
OBJECTIVE
To compare corneal haze and transforming growth factor (TGF)-beta expression in rat eyes with mechanical debridement of corneal epithelium or a chemically induced epithelial flap.


METHODS
Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.


METHODS
Sixty corneas from 60 Sprague-Dawley rats were treated in 1 of 4 ways using a 2.0 mm trephine: corneal epithelium mechanically removed (Group 1), central cornea exposed to 20% ethanol for 30 seconds (Group 2), corneal epithelial flap made by applying 20% ethanol for 30 seconds and flap amputated (Group 3), corneal epithelial flap repositioned after ethanol-assisted detachment of epithelium as in Group 3 (Group 4). Corneal haze was graded. The TGF-beta expression was measured in corneas and lacrimal glands using reverse transcription polymerase chain reaction and immunohistochemistry until day 30. Semiquantitative analysis was done in a density ratio of TGF-beta/beta-actin with image analyzer and densitometry.


RESULTS
Corneal haze was more severe in Groups 1 and 3 than in Groups 2 and 4. By day 7, mRNA expression of TGF-beta2 and type II receptor in corneas had increased more in Groups 1 and 3 than in Groups 2 and 4. In lacrimal glands, only TGF-beta1 in Group 3 increased until day 7. In corneas, staining of both TGF-beta1 and beta2 increased, more prominently in Groups 1 and 3. Lacrimal gland staining was more intense in Groups 1 and 3.


CONCLUSIONS
Well-positioned corneal epithelial flaps may decrease corneal haze by reducing expression of TGF-beta; inadvertent removal of an epithelial flap made by ethanol seems to exacerbate haze by increasing TGF-beta.
Lee
Jong Joo
JJ
Department of Ophthalmology, Seoul National University College of Medicine, #28 Yongon-dong, Chongno-gu, Seoul, Republic of Korea.
Kim
Mee Kum
MK
Shin
Kyung Sun
KS
Shin
Mi Sun
MS
Wee
Won Ryang
WR
Lee
Jin Hak
JH
D000818:Animals; D003315:Cornea / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D003318:Corneal Opacity / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D003646:Debridement; D019573:Epithelium, Corneal / Q000601:surgery*; D000431:Ethanol / Q000009:adverse effects; D015870:Gene Expression; D007124:Immunoenzyme Techniques; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013524:Surgical Flaps; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism*
D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D000431:Ethanol