Plasminogen activator inhibitor-I-related regulation of procollagen I (alpha1 and alpha2) by antitransforming growth factor-beta1 treatment during radiation-impaired wound healing.
OBJECTIVE
Plasminogen activator inhibitor (PAI)-1 mediates transforming growth factor-beta1 (TGF-beta1)-related signaling by stimulating collagen Type I synthesis in radiation-impaired wound healing. The regulation of alpha(I)-procollagen is contradictory in fibroblasts of different fibrotic lesions. It is not known whether anti-TGF-beta1 treatment specifically inhibits alpha(I)-procollagen synthesis. We used an experimental wound healing study to address anti-TGF-beta1-associated influence on alpha(I)-procollagen synthesis.


METHODS
A free flap was transplanted into the preirradiated (40 Gy) or nonirradiated neck region of Wistar rats: Group 1 (n = 8) surgery alone; Group 2 (n = 14) irradiation and surgery; Group 3 (n = 8) irradiation and surgery and anti-TGF-beta1 treatment. On the 14th postoperative day, skin samples were processed for fibroblast culture, in situ hybridization for TGF-beta1, immunohistochemistry, and immunoblotting for PAI-1, alpha1/alpha2(I)-procollagen.


RESULTS
Anti-TGF-beta1 significantly reduced TGF-beta1 mRNA (p < 0.05) and PAI-1 expression (p < 0.05). Anti-TGF-beta1 treatment in vivo significantly reduced alpha1(I)-procollagen protein (p < 0.05) and the number of expressing cells (p < 0.05) in contrast to significantly increased (p < 0.05) alpha2(I)-procollagen expression.


CONCLUSIONS
These results emphasize anti-TGF-beta1 treatment to reduce radiation-induced fibrosis by decreasing alpha1(I)-procollagen synthesis in vivo. alpha1(I)-procollagen and alpha2(I)-procollagen might be differentially regulated by anti-TGF-beta1 treatment. Increased TGF-beta signaling in irradiated skin fibroblasts seemed to be reversible, as shown by a reduction in PAI-1 expression after anti-TGF-beta1 treatment.
Schultze-Mosgau
Stefan
S
Department of Oral and Maxillofacial Surgery/Plastic Surgery, Freidrich-Schiller-University of Jena, Jena, Germany. stefan.schultze-mosgau@med.uni-jena.de
Kopp
Jürgen
J
Thorwarth
Michael
M
Rödel
Franz
F
Melnychenko
Ivan
I
Grabenbauer
Gerhard G
GG
Amann
Kerstin
K
Wehrhan
Falk
F
D000818:Animals; D024042:Collagen Type I / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D008297:Male; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D011832:Radiation Injuries / Q000517:prevention & control; D051381:Rats; D017208:Rats, Wistar; D013524:Surgical Flaps / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000276:immunology; D053773:Transforming Growth Factor beta1; D014945:Wound Healing
D024042:Collagen Type I; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1