Evaluacija citotoksičnosti resveratrola i piceatanola u makrofazima, T-stanicama i stanicama kože

The cytotoxicity of resveratrol and of piceatannol, a structural analog of resveratrol, was examined in cultured cells. Using a MTT-based assay, which measures the conversion of 3-[4,5-dimethylthiazol-2- yl]-2,5-diphenyl tetrazolium bromide (MTT) to a colored formazan product in living cells, resveratrol was found to inhibit the viability of transformed mouse macrophages, tumor-derived human T cells and human epidermoid carcinoma cells in a concentration-dependent manner, with the effect decreasing in the order: T cells (LC50 ~27 µmol L-1, 24 h; ~9 µmol L-1; 48h) > macrophages (LC50 ~29 µmol L-1, 24 h; 39 µmol L-1, 48 h) > skin cells (LC50 ~91 µmol L-1, 24 h ; ~66 µmol L-1, 48 h). Paradoxically, a high concentration of resveratrol (50 µmol L-1) inhibited the proliferation of all three cell types, and a low concentration (5 µmol L-1) stimulated the proliferation of macrophages. The viability of macrophages was also decreased by piceatannol in a concentration-dependent manner. The stimulation of macrophages with zymosan lowered the cytotoxicity of both resveratrol and piceatannol. Scanning electron microscopy of cells treated with resveratrol revealed changes in cellular morphology that were consistent with toxicity. In macrophages and skin cells, resveratrol (50 µmol L-1) induced a time-dependent increase in reduced glutathione levels but did not alter the background levels of thiobarbituric acid-reactive substances. Taken together, the present data indicate that resveratrol is toxic to cultured macrophages, T cells and skin cells at concentrations ≥25 µmol L-1, and that the cytotoxicity occurs via a mechanism that does not involve oxidative stress. Furthermore, the degree of toxicity of both resveratrol and piceatannol towards macrophages depends on the activation status of these cells, with zymosan-activated cells appearing more resistant than nonstimulated cells.Citotoksičnost resveratrola i piceatanola, strukturnog analoga resveratrola, ispitivana je u uzgojenim stanicama. Primjenom MTT-testa koji mjeri pretvorbu 3-[4,5-dimetiltiazol-2-il]2,5-difenil-tetrazolijeva bromida (MTT) u obojeni formazan produkt u živim stanicama, na|eno je da resveratrol inhibira preživljavanje transformiranih makrofaga miša, ljudskih tumorskih T-stanica i humanih stanica epidermoidnog karcinoma u ovisnosti o koncentraciji, a učinak opada redom: T-stanice (LC50 ~27 µmol L-1, 24 h; ~9 µmol L-1; 48 h) > makrofazi (LC50 ~29 µmol L-1, 24 h; 39 µmol L-1, 48 h) >stanice kože (LC50 ~91 µmol L-1, 24 h; ~66 µmol L-1, 48 h). Paradoksalno, pri visokoj koncentraciji resveratrola (50 µmol L-1) inhibirana je proliferacija svih triju tipova stanica, a pri niskim koncentracijma (5 µmol L-1) stimulirana je proliferacija makrofaga. Preživljavanje makrofaga bilo je tako|er smanjeno primjenom piceatanola ovisno o koncentraciji. Stimulacija makrofaga zimosanom smanjila je citotoksičnost i resveratrola i piceatanola. Skenirajuća elektronska mikroskopija stanica tretiranih resveratrolom pokazala je promjene u morfologiji stanica, što je bilo u skladu s toksičnosti. U makrofazima i stanicama kože resveratrol (50 µmol L-1) inducirao je porast smanjenja razina glutationa ovisan o vremenu, ali nije mijenjao osnovne razine reaktivnih spojeva tiobarbiturne kiseline. Gledajući skupno, prikazani rezultati indiciraju da je resveratrol toksičan za uzgojene makrofage, T-stanice i stanice kože pri koncentracijama ≥25 µmol L-1 i da se citotoksičnost zbiva mehanizmom koji ne uključuje oksidativni stres. Nadalje, stupanj toksičnosti resveratrola i piceatanola prema makrofagima ovisi o aktivacijskom statusu tih stanica, pri čemu su stanice aktivirane zimosanom rezistentnije od nestimuliranih stanica