Expression of apoptosis, autophagy and necroptosis effectors in cells of rat hippocampus after excessive F<sup>-</sup> consumption

The work examined the expression of apoptosis, autophagy and necroptosis markers in hippocampal cells of rats after long-term consumption of excessive F- doses at the transcriptional and translational levels. Male Wistar rats were divided into 4 groups receiving 0.4 (control), 5, 20 and 50 mg/l F- (as NaF) for 12 months. The changes in contents of effectors of mitochondrial (Bcl-2, Bax, Caspase-9, Caspase-3) and receptor (Caspase-8, Fas) pathways of apoptosis, mediators (Ulk-1, Beclin-1) and modulators (AMPK, Ark, mTOR) of autophagy, as well as that of necroptosis (RIP and MLKL) were assessed by immunoblotting, the gene expression (Bcl2, Bax, Casp3, Ulk1, Beclin1, Prkaa1, Akt, and mTor) – by real-time PCR. In the hippocampus of F – exposed animals, the expression ratio of Bcl2/Bax genes and Bcl-2/Bax proteins decreased, caspase-9 and caspase-3 were activated, but the level of caspase-8 and membrane Fas receptor remained stable. Long-term F- consumption had no effect on the content of autophagy initiator Ulk-1 and protein kinases AMPK, Akt and mTOR, but resulted in inhibition of key autophagy mediator Beclin-1. The expression level of necroptosis RIP and MLKL effectors in the hippocampal cells of rats received excessive F- did not change as well. Thus, long-term F- exposure was accompanied by activation of apoptosis, mainly through the mitochondrial pathway, at the background of autophagy suppression.