The aminoterminal propeptide of
type III procollagen (
PIIINP) in serum has been shown to correlate with fibrillogenesis, and thus to be a potential direct marker of
type III collagen deposition. The aim of the study was to investigate the correlation between changes in serum
PIIINP and formation of granulation tissue during pharmacological suppression. Granulation tissue was induced in rats by the implantation of viscose
cellulose sponges. Pharmacological suppression was achieved by
cyclophosphamide treatment. To distinguish between the isolated effect of
cyclophosphamide and the influence of the
weight loss caused by treatment,
weight loss caused by
starvation was investigated. In untreated rats, serum
PIIINP and
wound fluid
PIIINP were related to formation of granulation tissue (serum: r = 0.58, p < 0.05;
wound fluid: r = 0.56, p < 0.05). In rats treated with
cyclophosphamide,
collagen deposition and formation of granulation tissue were markedly reduced, as compared within the untreated rats (6% vs 33%, p = 0.01).
Wound fluid
PIIINP reflected the sparse
collagen deposition (r = 0.48, p < 0.05), whereas serum
PIIINP decreased (-35%, p < 0.01) and was not correlated with the formation of granulation tissue. In starved rats, with a
weight loss of 8%, formation of granulation tissue, vascular density, and
collagen deposition were not reduced.
Wound fluid
PIIINP reflected the formation of granulation tissue (r = 0.52, p < 0.05), whereas serum
PIIINP remained unchanged despite normal formation of granulation tissue.
Starvation of rats without implants caused a decrease in serum
PIIINP (-33%(-)-48%, p < 0.01). We conclude that during
cyclophosphamide treatment and after a moderate
weight loss, serum
PIIINP is not a valid marker of fibrillogenesis. However, in normal rats with free access to food, changes in serum
PIIINP mirror fibrillogenesis. Furthermore, our study provides experimental evidence consistent with the hypothesis that
wound fluid
PIIINP directly mirrors the local formation of granulation tissue, independent of
weight loss and
cyclophosphamide treatment.