Synergistic effect of schizandrin A and DNase I knockdown on high glucose induced beta cell apoptosis by decreasing intracellular calcium concentration.

Objective: To explore the synergistic effect of deoxyribonuclease I (DNase I) knockdown combined with Schizandrin A (Sch A) in protecting islet beta-cells (β-cells) from apoptosis under high-glucose (HG) conditions.

Methods: The concentration of Sch A was detected by Cell Counting Kit-8 (CCK-8). High glucose-cultured rat insulinoma beta cell line (RIN-M5F) cells were treated with Sch A and transfected with DNase I small interfering RNA (siRNA). Cell apoptosis rate and apoptosis-related protein level were examined by flow cytometry and Western blot method respectively. In addition, Na-K-adenosine triphosphatease (Na-K-ATPase) and Ca-Mg-ATPase activity, cell membrane potential, and intracellular Ca concentration was also examined respectively.

Results: Our study revealed that HG stimulation can cause a significant increase in DNase I level and cell apoptosis rate. However, Sch A combined with DNase I knockdown can significantly decrease the cell apoptosis rate and apoptosis-related protein levels such as BAX ( 0.05) and Caspase-3 ( 0.01). In addition, we also found that the combination of Sch A and DNase I knockdown can dramatically increase cell membrane potential level, Na-K-ATPase, and Ca-Mg-ATPase activity. Meanwhile, intracellular Ca concentration was also found to be significantly decreased by the synergistic effect of Sch A and DNase I knockdown.

Conclusion: Overall, our study reveals a synergistic effect of Sch A and DNase I knockdown in protecting β-cells from HG-induced apoptosis.