Journal of Dental Research, Vol 69, 1555-1559, Copyright © 1990 by International & American Associations for Dental Research Online Journals
Chondrocyte-like colony formation of mesenchymal cells by dentin extracts in agarose gel culture
K. Harada, S. Oida, S. Sasaki and S. Enomoto
Second Department of Oral Surgery, Tokyo Medical and Dental University, Japan.
In this study, the effects of guanidine extracts from demineralized bovine
dentin matrix on rat mesenchymal cells were investigated by use of an
agarose gel culture. The dentin extracts were divided into water-soluble
and -insoluble fractions. Rat mesenchymal cells obtained from the
cultivation of skeletal muscle tissue and embedded in agarose gel were
treated with these two fractions. After three weeks of cultivation, the
treated cells formed colonies that were stained metachromatically with
toluidine blue in a dose-dependent manner. The activity necessary to form
chondrocyte-like colonies by the water-insoluble fraction was significantly
higher than that by the water-soluble fraction. Each chromatographic
fraction of the water-insoluble part of dentin extracts on tandem Sephacryl
S-200 High-resolution columns was also investigated. Chondrocyte-like
colony-forming activity was concentrated in a single fraction. However, the
electrophoretic pattern of this fraction revealed that there were still
some bands of molecular weight between 18 and 30 kDa. According to the
Western blot analysis of this fraction, there was a band corresponding to
purified transforming growth factor beta (TGF-beta) under the non-reducing
condition. After reduction, this band disappeared and we found a band
corresponding to a component of 13 kDa as well as TGF-beta. These findings
suggest that TGF-beta is present not only in bone but also in the dentin
matrix.
