Expression of microsomal prostaglandin e synthase-1 in fibroblasts of rabbit alkali-burned corneas.
OBJECTIVE
Prostaglandin E2 is related to wound healing. Three different prostaglandin E synthases have been identified: microsomal prostaglandin E synthase (mPGES)-1, mPGES-2, and cytosolic prostaglandin E synthase. This study examined mPGES-1 expression in the cornea during the reparative process that occurs after an alkali burn.


METHODS
mPGES-1 messenger RNA (mRNA) and protein expression levels were examined by reverse transcription-polymerase chain reaction and Western blot analysis. Localization of mPGES-1 mRNA was examined by in situ hybridization. Using immunostaining, the localization of mPGES-1, cyclooxygenase (COX)-2, and alpha-smooth muscle actin (alpha-SMA) protein was studied.


RESULTS
Although mPGES-1 mRNA is expressed in normal cornea, after a corneal injury, a progressive increase of mPGES-1 mRNA occurs. In this study, 2-6 weeks after injury, mPGES-1 mRNA was detected in the stromal spindle cells. Western blot analysis also showed that mPGES-1 protein expression was observed in normal cornea, with an increase noted from 2 to 4 weeks after corneal injury. mPGES-1 immunoreactivity was negative in normal cornea; however, starting at 2 weeks after injury, positive staining of the stromal spindle cells was noted. Although COX-2 and alpha-SMA immunoreactivities were negative in the stroma of normal cornea, after injury, staining was observed in the stromal spindle cells.


CONCLUSIONS
alpha-SMA-positive cells and myofibroblasts express mPGES-1 mRNA and protein, and in addition, mPGES-1 colocalized with COX-2, suggesting that myofibroblasts synthesize prostaglandin E2 and may act on and accelerate corneal wound healing.
Kawamura
Aruha
A
Department of Analytic Human Pathology, Nippon Medical School, Sendagi, Tokyo, Japan. aruaru3199@yahoo.co.jp
Tatsuguchi
Atsushi
A
Ishizaki
Masamichi
M
Takahashi
Hiroshi
H
Fukuda
Yuh
Y
D000199:Actins / Q000378:metabolism; D000468:Alkalies; D000818:Animals; D002057:Burns, Chemical / Q000201:enzymology* / Q000378:metabolism; D003315:Cornea / Q000201:enzymology / Q000378:metabolism; D065306:Corneal Injuries; D051546:Cyclooxygenase 2 / Q000378:metabolism; D005126:Eye Burns / Q000139:chemically induced / Q000201:enzymology* / Q000378:metabolism; D005347:Fibroblasts / Q000201:enzymology*; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism; D000071876:Prostaglandin-E Synthases; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D014018:Tissue Distribution
D000199:Actins; D000468:Alkalies; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D019746:Intramolecular Oxidoreductases; C000605862:PTGES protein, human; C000605863:PTGES2 protein, human; D000071876:Prostaglandin-E Synthases