Tetrahydroxy stilbene glycoside protects N2a/APP695swe cells by regulating Mfn2

Background: To investigate the effect of tetrahydroxy stilbene glycoside (TSG) on mitochondrial function and apoptosis of N2a/APP695swe cells by regulating the expression level of mitofusin 2 (Mfn2) and to further explore the mechanism of the effect of TSG on cell protection. Methods: The CCK8 method was used to analyze the cell viability of N2a/APP695swe cells treated with different concentrations of TSG for 48 h and to select the appropriate concentration of TSG for subsequent experiments. N2a/WT cells and N2a/APP695swe cells were routinely cultured in vitro, and the experimental cells were divided into four groups: the blank control group (WT group): N2a/WT cells, routinely cultured; the model group (APP group): N2a/APP695swe cells, routinely cultured; the treatment group (TSG group): N2a/APP695swe cells, appropriate concentrations of TSG intervention; and the inhibition group (siRNA group): N2a/APP695swe cells, siRNA used to inhibit Mfn2 expression, appropriate concentrations of TSG intervention. The JC-1 method was used to detect mitochondrial membrane potential, the TUNEL method was used to observe apoptosis by fluorescence microscopy, WB was used to detect protein expression of Mfn2, Bcl-2, Bax, Caspase3, Caspase9, and Cytochrome C, and RT‒qPCR was used to detect Mfn2, Bcl-2, Bax, Caspase3, and Caspase9 mRNA expression. Results: A concentration of 100 μmol/L TSG was selected for the experiment ( P < 0.01). Compared with the WT group, the APP group showed decreased membrane potential ( P <0.05), increased apoptosis ( P <0.05), increased expression of cytochrome C, Bax, Caspase3, and Caspase9 ( P <0.05), and decreased expression of Mfn2 and Bcl-2 ( P <0.05). Compared with the APP group, the TSG group showed increased membrane potential ( P <0.05), decreased apoptosis rate ( P <0.05), decreased expression of Bax, Caspase3, Caspase9, and cytochrome C ( P <0.05), and elevated expression of Mfn2 and Bcl-2 ( P <0.05) in the siRNA group. Caspase9 and cytochrome C expression was decreased ( P <0.05), Bcl-2 expression was elevated ( P <0.05), and Mfn2 expression was decreased ( P <0.05) in the siRNA group. Compared with the TSG group, the membrane potential level was decreased ( P <0.05) and the apoptosis rate was increased ( P <0.05) in the siRNA group, and the expression of Bax, Caspase3 and Caspase9, and cytochrome C was elevated ( P <0.05) and the expression of Mfn2 and Bcl-2 was decreased ( P <0.05) in the siRNA group. Conclusion: TSG has a clear protective effect in N2a/APP695swe cells, which may be associated with upregulating Mfn2, elevating mitochondrial membrane potential, increasing Bcl-2 expression and reducing the release of Bax, Caspase3, Caspase9, and cytochrome C, thereby ameliorating cellular mitochondrial dysfunction and inhibiting apoptosis.