BORON MODULATES EXTRACELLULAR-MATRIX AND TNF-ALPHA SYNTHESIS IN HUMANFIBROBLASTS

Boric acid was not mitogenic for human fibroblasts and it did not chan ge cell viability until 0.5% (w/v), Boric acid treatment affected the metabolism of human dermal fibroblasts in culture, decreasing the synt hesis of extracellular matrix macromolecules such as proteoglycans, co llagen, and total proteins. It also increased the release of these mol ecules into the culture medium. The principal proteins secreted into t he medium after boric acid treatment had molecular masses of 90, 70, 5 8, 49, and 43 kDa and faint bands were detected by electrophoresis bet ween 14 and 30 kDa. hsp 70 and TNF alpha were detected among the secre ted proteins by immunoblotting, and the amount of TNF alpha released w as quantified by radioimmunoassay. Total mRNA levels were higher after boric acid treatment and peaked after 6 h of treatment. TNF alpha mRN A was undetectable in unstimulated fibroblasts and two TNF alpha mRNA bands were detected after stimulation: immature mRNA (4.8 kb) and matu re TNF alpha mRNA (1.9 kb). Thus, the effects of boric acid observed i n wound repair in vivo may be due to TNF alpha synthesis and secretion . (C) 1998 Academic Press.