Connective tissue growth factor and its correlation to other growth factors in experimental granulation tissue

Connective tissue growth factor (CTGF) is upregulated in a variety of fibrotic disorders, probably secondary to the activation and production of transforming growth factor-beta (TGF- g ). We have studied the expression of CTGF in a rat wound-healing model using Northern blot, in situ hybridization, and immunohistochemistry. The expression of CTGF mRNA in Northern blot and immunohistochemistry were correlated to the expression of TGF- g 1 and platelet-derived growth factor (PDGF). Northern hybridization showed the maximum expression of CTGF mRNA on day 14, whereas TGF- g 1 expression was maximal on days 7 and 14 and the time-related changes were smaller than for CTGF. PDGF A and PDGF B mRNA expressions were at maximum on day 14 and on day 21, respectively. In situ hybridization showed that fibroblast-like cells expressed CTGF most intensively, expression declining rapidly after day 14. CTGF mRNA and protein were found in blood vessel cells during the first week. In immunohistochemistry, all gro...