Corneal epithelial VEGF and cytochrome P450 4B1 expression in a rabbit model of closed eye contact lens wear.
OBJECTIVE
The similar and overlapping activity of VEGF and the potent corneal-derived angiogenic eicosanoid 12(R)-HETrE calls for a study of the temporal relationship in the expression of these two autocoids. Since recent evidence suggests that hypoxia induces the expression of a CYP4B1 mRNA which might be involved in the conversion of arachidonic acid to 12(R)-HETrE, we determined its time-dependent expression and correlated it to that of VEGF mRNA in the rabbit model of closed eye contact lens-induced injury.


METHODS
Rabbit eyes were fitted with contact lenses followed by a silk suture tarsorrhaphy. The anterior surface was analyzed at 2-, 4- and 7-days by slit lamp biomicroscopy, subjective inflammatory scoring and corneal pachymetry. Corneal epithelium was scraped and CYP4B1 and VEGF mRNA levels were measured by Southern hybridization of RT-PCR products amplified from a single cornea with specific primers.


RESULTS
Corneal thickness and inflammatory scores increased in a time dependent manner in the model of closed eye contact lens induced hypoxic injury. Corneal epithelial CYP4B1 and VEGF mRNAs, as well as the production of the angiogenic eicosanoid, 12-HETrE, increased in a time-dependent manner and correlated with the in situ inflammatory response.


CONCLUSIONS
The present study documents the increased expression of CYP4B1 isoform in the corneal epithelium during hypoxic injury in vivo. It also demonstrates the presence of VEGF mRNA in the corneal epithelium and its increased expression in this model of hypoxic injury. All together, the results of this study raise the possibility of interaction between these autocoids, VEGF and CYP4B1-12(R)-HETrE, in mediating the neovascularization response induced by the prolonged hypoxic state brought about by closed eye contact lens wear.
Mastyugin
V
V
Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA.
Mosaed
S
S
Bonazzi
A
A
Dunn
M W
MW
Schwartzman
M L
ML
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000378:metabolism; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D015139:Blotting, Southern; D003261:Contact Lenses / Q000009:adverse effects*; D016510:Corneal Neovascularization / Q000209:etiology / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D016228:Endothelial Growth Factors / Q000096:biosynthesis* / Q000235:genetics; D019573:Epithelium, Corneal / Q000378:metabolism*; D005143:Eyelids / Q000601:surgery; D000860:Hypoxia / Q000209:etiology / Q000378:metabolism*; D007634:Keratitis / Q000209:etiology / Q000378:metabolism*; D008222:Lymphokines / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism; D023421:Models, Animal; D012333:RNA, Messenger / Q000096:biosynthesis; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D017931:DNA Primers; D016228:Endothelial Growth Factors; D008222:Lymphokines; D008840:Microfilament Proteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; C095029:cytochrome P-450 CYP4B1