Srt 1720

According to the manufacturer's instructions, the MitoTracker Green (Beyotime, C1048, China), MitoSOX-Red (Beyotime, C1045, China), and JC-1 fluorescent probe (Beyotime, C2006, China) were used to detect mitochondrial membrane potential changes in NP cells. The morphology of mitochondria of NP cells was observed by transmission electron microscopy (TEM; H-9500; Hitachi, Tokyo, Japan). The decrease in mitochondrial membrane potential is a hallmark event in the early stages of apoptosis [76 ,77 (link)]. JC-1 (5,5′,6,6′-tetrachloro1,1′,3,3′-tetramethylbenzimidazolylcarbocyanine iodide) is an ideal fluorescent probe widely used to detect mitochondrial membrane potential (△Ψm). JC-1 monomers can produce green fluorescence (△Ψm↓) while JC-1 aggregates can produce red fluorescence (△Ψm↑) [78 ,79 (link)]. We measured the proportion of mitochondrial depolarization by comparing the relative proportions of red and green fluorescence. Therefore, the transition of JC-1 from red fluorescence to green fluorescence can detect the decrease of cell membrane potential and serve as an early detection indicator of apoptosis. Then we used the selective SIRT1 activator (SRT-1720, Beyotime, SC0267) and the selective SIRT1 inhibitor (EX-527, MCE, HY-15452) to verify the mechanism of PEVs repairing impaired mitochondria in pathological NP cells. All experiments were performed with four replicates each.