Antifibrotic effect by activation of peroxisome proliferator-activated receptor-gamma in corneal fibroblasts.
OBJECTIVE
The transformation of quiescent keratocytes to active phenotypes and the ensuing fibrotic response play important roles in corneal scar formation. This study aims to observe the antifibrotic effect of peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist on corneal fibroblasts cultured in vitro, and to explore the potential application of peroxisome proliferator-activated receptor agonist to the prevention of corneal opacity following wound repair.


METHODS
Rabbit corneal keratocytes were cultured in a medium containing 10% serum to induce their transformation to fibroblasts and myofibroblasts, which are similar to those that repair corneas. After incubation with the PPARgamma agonist pioglitazone at different concentrations, the effect of pioglitazone on the migration, contractility, and viability of corneal fibroblasts was examined. The secretion of matrix metalloproteinase-2 and matrix metalloproteinase-9 was determined by gelatin zymography, and the synthesis of collagen I and fibronectin was investigated by western blotting.


RESULTS
Treatment with pioglitazone at concentrations ranging from 1 to 10 mum significantly decreased corneal fibroblast migration, as determined by scrape-wound assay, inhibited corneal fibroblast-induced collagen lattice contraction, and reduced MMP-2 and MMP-9 secretion into the supernatant of cell cultures in a dose-dependent manner. The expression of fibronectin was significantly decreased, while the expression of collagen I was only decreased when treated with 10 mum pioglitazone. Cell viability was not evidently changed compared to the control.


CONCLUSIONS
This in vitro study demonstrated the anti-fibrotic effect of pioglitazone, suggesting that activation of PPARgamma may be a new approach for the treatment of corneal opacity and scar formation in the corneal wound healing process.
Pan
Hongwei
H
Department of Ophthalmology, Medical College, Jinan University, Guangzhou, China. panhongwei@hotmail.com
Chen
Jiansu
J
Xu
Jintang
J
Chen
Miaojiao
M
Ma
Rong
R
D000199:Actins / Q000378:metabolism; D000818:Animals; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D024042:Collagen Type I / Q000378:metabolism; D003315:Cornea / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D005353:Fibronectins / Q000378:metabolism; D005355:Fibrosis; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D047495:PPAR gamma / Q000378:metabolism*; D000077205:Pioglitazone; D011817:Rabbits; D045162:Thiazolidinediones / Q000494:pharmacology
D000199:Actins; D024042:Collagen Type I; D005353:Fibronectins; D047495:PPAR gamma; D045162:Thiazolidinediones; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D000077205:Pioglitazone