Increased level of apoptosis in rat brains and SH-SY5Y cells exposed to excessive fluoride-A mechanism connected with activating JNK phosphorylation

► The apoptotic death rate and phospho-JNK at protein level were obviously increased in brains of the rats and in SH-SY5Y cells exposed to high amount of fluoride. ► When SH-SY5Y cells were singly treated with SP600125, an inhibitor of phospho-JNK, the decreased expression of phospho-JNK, but no apoptosis, was detected. ► After JNK phosphorylation in the cultured cells was inhibited by SP600125, the treatment with high-fluoride did not induce the increase of apoptosis. ► The results indicated that exposure to excessive fluoride resulted in the increase of apoptosis in rat brains and SH-SY5Y cells, in which one of the mechanisms might be activating JNK phosphorylation.