Action of boron at the molecular level: effects on transcription and translation in an acellular system.

It has been shown that boric acid has well-defined biological effects such as stimulation of wound healing in vivo, release of growth factors and cytokines, and increase of the extracellular matrice turnover. We examined its action at the molecular level, using cell-free systems of transcription (isolated placenta nuclei) and translation (wheat germ extract). We found that 10 mM boric acid greatly increased RNA synthesis, measured by absorbance at 260 nm (x 6.4) or by [3H]-UTP uptake (x 11). Full-length functional mRNA was produced because proteins of 14-80 kDa were translated. Among these proteins, factors involved in angiogenesis and, subsequently, in wound healing (VEGF and TGFbeta) were identified by slot blot, whereas growth factors such as FGF1 and TNFalpha were not detected. These results demonstrate that boron may contribute to biological cell activities at both the transcription and translation levels. However, the mechanism of action is still not known.