Inhibitory effects of Salvianolic acid B on apoptosis of Schwann cells and its mechanism induced by intermittent high glucose

摘要

Aims: To investigate protective effects of Salvianolic acid B (Sal B) on the intermittent high glucose (IHG)-induced oxidative stress, mitochondrial pathway activation and Schwann cell (SC) apoptosis in vitro. Main methods: SCs were primarily cultured and exposed to the different conditions. Apoptosis was confirmed by the Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method and concentration of 8-hydroxy-2-deoxy Guanosine (8-OHdG) was detected by Elisa. Intracellular ROS generation and mitochondrial transmembrane potential (ΔΨm) were detected by flow cytometry analysis. Quantitative real-time reverse transcriptase PCR was performed to analyze the expression levels of Bax and BcL-2. Western blot was performed to analyze the expression levels of some important transcription factors and proteins. Key findings: Treatment with Sal B inhibited the IHG-induced oxidative stress by reducing ROS production and 8-OHdG levels, mitochondrial depolarization and apoptosis in SCs in a dose-dependent manner. Furthermore, treatment with Sal B down-regulated the IHG-induced release of cytochrome c, AIF nuclear translocation and Bax expression, but mitigated the IHG-mediated down-regulation of BcL-2 expression in SCs. In addition, treatment with Sal B attenuated the IHG-induced activation of caspase-9 and caspase-3 and minimized the cleavage of PARP in SCs. Significance: Our results indicated that IHG induced SC apoptosis in both caspase-dependent and caspase-independent pathways by activating the mitochondrial pathway. Sal B inhibited the IHG-induced oxidative stress, activation of the mitochondrial pathway and apoptosis in SCs.