Inhibition of p38MAP kinase suppresses fibrogenic reaction in conjunctiva in mice.
OBJECTIVE
To examine the effects of blocking p38 mitogen-activated protein kinase (MAPK) on post-injury conjunctival scarring in mice. Its effects on the behaviors of cultured subconjunctival fibroblasts were also investigated.


METHODS
An in vivo study was conducted using an adenoviral vector carrying a dominant-negative (DN)-p38MAPK gene. A circumferential incision was made in the equatorial conjunctiva by scissors in the right eye of generally anesthetized adult C57BL/6 mice. DN-p38MAPK-expressing adenoviral vector was topically applied. The left control eye received non-functioning adenoviral vector. At 2, 5, and 7 days (each, n=22) the eyes were processed for histological or immunohistochemical examination to evaluate the tissue scarring. The expressions of type-I collagen and growth factors were evaluated by real time-reverse transcriptase-polymerase chain reaction. The effects of p38MAPK inhibitor on the proliferation, migration, and fibrogenic gene/protein expression of cultured human fibroblasts were also studied.


RESULTS
The in vivo DN-p38MAPK gene introduction blocked the phospho-p38 expression with reduction of myofibroblast generation and suppression of mRNA expression of connective tissue growth factor (CTGF) and monocyte/macrophage chemoattractant protein-1 (MCP-1) in the mouse-injured conjunctiva. Blocking p38MAPK signal in the fibroblasts by a chemical inhibitor counteracted TGFbeta1's enhancement of expressions of type-I collagen, fibronectin, and CTGF. It also retarded cell migration, but cell proliferation was unchanged.


CONCLUSIONS
Inhibiting p38MAPK signal impairs the fibrogenic reaction induced by the subconjunctival fibroblasts in vivo and in vitro, suggesting its potential effectiveness in preventing excessive scarring following glaucoma filtering surgery.
Yamanaka
Osamu
O
Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan. yamanaka@wakayama-med.ac.jp
Saika
Shizuya
S
Ohnishi
Yoshitaka
Y
Kim-Mitsuyama
Shokei
S
Kamaraju
Anil K
AK
Ikeda
Kazuo
K
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002921:Cicatrix / Q000517:prevention & control*; D003094:Collagen / Q000235:genetics; D024042:Collagen Type I; D003228:Conjunctiva / Q000187:drug effects / Q000201:enzymology* / Q000293:injuries* / Q000473:pathology; D055513:Connective Tissue Growth Factor; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects; D005355:Fibrosis / Q000378:metabolism; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005799:Genes, Dominant; D005822:Genetic Vectors; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D017874:Immediate-Early Proteins / Q000235:genetics; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D051785:Smad Proteins / Q000378:metabolism; D014945:Wound Healing / Q000187:drug effects; D014950:Wounds, Penetrating / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; D024042:Collagen Type I; D004791:Enzyme Inhibitors; D016326:Extracellular Matrix Proteins; D007093:Imidazoles; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011725:Pyridines; D051785:Smad Proteins; D055513:Connective Tissue Growth Factor; D003094:Collagen; D048051:p38 Mitogen-Activated Protein Kinases; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole