Selective modulation of collagen gene expression by different isoforms of platelet-derived growth factor in experimental wound healing.
Subcutaneous sponges in rat were used as a wound model to study the changes in collagen gene expression induced by different isoforms of platelet-derived growth factor (PDGF). The steady state levels of proalpha1(I) and proalpha1(III) collagens rose markedly in response to PDGF-AB treatment. In marked contrast to PDGF-AB, PDGF-BB exerted a down-regulatory effect on the expression of type I and III procollagen mRNA levels. In situ hybridisation signal for proalpha1(I) collagen mRNA was most prominent in the periphery of the sponges in response to PDGF-AB. In PDGF-AA and PDGF-BB treated sponges, however, the hybridisation signal for proalpha1(I) collagen mRNA was evenly distributed. Immunolabellings demonstrated the presence of type I and III collagen epitopes and thus revealed the deposition of these proteins into developing granulation tissue. The volume of ingrown granulation tissue was estimated by measuring the cross-sectional area of the samples. PDGF-AB and PDGF-BB were both effective resulting in a significant increase in the amount of granulation tissue. However, only a limited enhancement of granulation tissue ingrowth was observed in response to PDGF-AA treatment. To conclude, PDGF-AB and PDGF-BB induced significantly the ingrowth of repair tissue in wounds. PDGF-AB distinctively upregulated collagen gene expression, while PDGF-BB primarily seemed to be mitogenic.
Lepistö
J
J
Department of Surgery, University of Turku, FIN-20520 Turku, Finland.
Peltonen
J
J
Vähä-Kreula
M
M
Söderström
K
K
Niinikoski
J
J
Laato
M
M
D000818:Animals; D015870:Gene Expression; D008297:Male; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011347:Procollagen / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014945:Wound Healing / Q000502:physiology*
D010982:Platelet-Derived Growth Factor; D011347:Procollagen; D012333:RNA, Messenger