Inhibition by female sex hormones of collagen degradation by corneal fibroblasts.
OBJECTIVE
Corneal fibroblasts contribute to collagen remodeling in the corneal stroma in part by mediating collagen degradation. Given that corneal structure is influenced by sex hormone status, we examined the effects of sex hormones on collagen degradation by corneal fibroblasts.


METHODS
Rabbit corneal fibroblasts were cultured in three-dimensional collagen gels with or without sex hormones including 17β-estradiol, progesterone, testosterone, and dehydroepiandrosterone (DHEA). Collagen degradation was determined by measurement of hydroxyproline after acid hydrolysis. The expression and activity of matrix metalloproteinases (MMPs) were evaluated by immunoblot analysis and gelatin zymography. The phosphorylation of mitogen-activated protein kinases (MAPKs) and the nuclear factor-kappa B (NF-κB) inhibitor NF kappa B Inhibitor-alpha (IκB-α) in corneal fibroblasts was examined by immunoblot analysis. Cell proliferation and viability were evaluated by measurement of bromodeoxyuridine incorporation and the release of lactate dehydrogenase, respectively.


RESULTS
17β-Estradiol and progesterone each inhibited interleukin (IL)-1β-induced collagen degradation by corneal fibroblasts in a concentration-dependent manner, whereas testosterone and DHEA had no such effect. MMP expression and activation in corneal fibroblasts exposed to IL-1β were also inhibited by 17β-estradiol and progesterone. These female sex hormones did not affect cell proliferation or viability. Both 17β-estradiol and progesterone inhibited the IL-1β-induced phosphorylation of p38 MAPK without affecting that of the MAPKs extracellular Signal-regulated Kinase (ERK) or c-jun N-terminal kinase (JNK). 17β-Estradiol also inhibited the IL-1β-induced phosphorylation of IκB-α.


CONCLUSIONS
17β-Estradiol and progesterone inhibited MMP expression and activity in IL-1β-stimulated corneal fibroblasts and thereby suppressed collagen degradation by these cells.
Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, Ube City, Yamaguchi, Japan.
Hongyan
H
Zhou
Kazuhiro
K
Kimura
Tomoko
T
Orita
Teruo
T
Nishida
Koh-Hei
KH
Sonoda
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000037:antagonists & inhibitors* / Q000378:metabolism; D003319:Corneal Stroma / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D003687:Dehydroepiandrosterone / Q000494:pharmacology / Q000502:physiology; D004958:Estradiol / Q000494:pharmacology / Q000502:physiology; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015870:Gene Expression; D012739:Gonadal Steroid Hormones / Q000494:pharmacology* / Q000502:physiology; D051550:I-kappa B Kinase / Q000235:genetics / Q000378:metabolism; D053583:Interleukin-1beta / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011374:Progesterone / Q000494:pharmacology / Q000502:physiology; D059748:Proteolysis; D011817:Rabbits; D015398:Signal Transduction; D013739:Testosterone / Q000494:pharmacology / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
D012739:Gonadal Steroid Hormones; D053583:Interleukin-1beta; D013739:Testosterone; D003687:Dehydroepiandrosterone; D011374:Progesterone; D004958:Estradiol; D003094:Collagen; D051550:I-kappa B Kinase; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020782:Matrix Metalloproteinases