Divergent effects of resveratrol, a polyphenolic phytostilbene, on free radical levels and type of cell death induced by the histone deacetylase inhibitors butyrate and trichostatin A.

We investigated the effects of the polyphenolic phytostilbene resveratrol on the steady-state free radical (FR) concentration and mode of cell death induced by the histone deacetylase inhibitors butyrate and trichostatin A. (i) There was no correlation between cell death induction by butyrate or trichostatin A (TSA) and FR levels. (ii) Treatment with resveratrol or N-acetyl-l-cystein (NAC) of cells, in which the FR concentration was high, resulted in an almost complete reduction of FR levels. (iii) When, however, the cellular FR concentration was marginal, resveratrol caused a minor, and NAC a marked increase of FRs as well as of the extent of cell death. Thus, resveratrol and NAC acted as antioxidants only when the cellular FR levels were high, and acted as pro-oxidants when facing a low FR concentration. (iv) Since resveratrol and the antioxidant NAC exhibited analogous effects, it is concluded that the observed actions of resveratrol are due to polyphenolic redox reactions and not related to the stilbene moiety of the molecule. (v) The results indicate that the redox status of a given cell type plays an important role in determining whether resveratrol and other antioxidants promote cell death or protect cells from it.

Na+/H+ exchange in primary, secondary and n-butyrate-treated cultures of ruminal epithelial cells: short communication.

Rate of amiloride-sensitive Na+ uptake into cultured rumen epithelial cells was studied in order to clarify the influence of culture conditions on Na+/H+ exchange (NHE). Cell cultures were exposed to Na-n-butyrate or not for seven days or subcultured. On the 14th day of culturing, primary cell cultures without butyrate exposure showed both non-stratified and stratified growth. Na-n-butyrate treated 14-day-old cultures and 3-day-old subcultures contained mostly non-stratified, i.e. non-keratinised cells. Both n-butyrate treatment and subculturing increased total and amiloride-sensitive Na+ uptake. Our results indicate that Na+ uptake via NHE is determined by the amount and the ratio of non-stratified (non-keratinised) cells.