Biglycan gene expression in UVR-exposed rabbit corneas.
OBJECTIVE
It is known that stromal proteoglycans play an important role in the hydration and transparency of the mammalian cornea. Proteoglycans have been described as a pathological deposit in climatic proteoglycan stromal keratopathy, which is associated with chronic ultraviolet radiation (UVR) exposure. The expression of dermatan sulfate proteoglycan biglycan in the cornea was thus studied after exposure of rabbit eyes to UVR.


METHODS
New Zealand albino rabbit corneas were exposed to UVR at 310 nm at the dose producing biomicroscopically significant keratitis (0.47 J/cm2). Animals were killed 3, 7 and 28 days after exposure (five rabbits in each group). Five rabbits were used as controls and did not receive any UVR treatment. Expression of biglycan mRNA in the corneas was investigated by competitive reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
There was no expression of biglycan mRNA in the control group. In the UVR-exposed groups, biglycan mRNA had still not been expressed 3 days after exposure. The expression of biglycan mRNA was observed in all UVR-treated corneas 7 days after exposure (p < 0.05). By 28 days after UVR exposure the expression of biglycan mRNA had decreased (not statistically significant).


CONCLUSIONS
There is no detectable biglycan gene expression in the normal rabbit cornea. Ultraviolet radiation exposure leads to a distinct expression of biglycan mRNA in the rabbit cornea that decreases 4 weeks after exposure, indicating the involvement of biglycan in the corneal repair process. Biglycan appears to be a novel marker of corneal wound healing.
Podskochy
Alexander
A
St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden. alexander.podskochy@lio.se
Koulikovska
Marina
M
Fagerholm
Per
P
van der Ploeg
Ingeborg
I
D000818:Animals; D058578:Biglycan; D003315:Cornea / Q000528:radiation effects*; D016326:Extracellular Matrix Proteins; D005260:Female; D015870:Gene Expression / Q000528:radiation effects*; D007634:Keratitis / Q000209:etiology / Q000378:metabolism*; D011509:Proteoglycans / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D011833:Radiation Injuries, Experimental / Q000209:etiology / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014466:Ultraviolet Rays
D058578:Biglycan; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D012333:RNA, Messenger