Leonurine protects against dexamethasone-induced cytotoxicity in pancreatic β-cells via PI3K/Akt signaling pathway.

Glucocorticoid excess induces pancreatic β-cell apoptosis and insulin secretion impairment, which may lead to hyperglycemia and steroid diabetes. Leonurine is a natural alkaloid extracted from the Herba leonuri, which has been widely used in the treatment of obstetric and gynecological diseases. However, whether leonurine performs a protective role in pancreatic β-cells remains unknown. In this study, we evaluated the effect of leonurine on dexamethasone -treated β-cells. Our data showed that leonurine inhibited dexamethasone-induced INS-1 cell apoptosis and facilitated cell proliferation. Moreover, leonurine attenuated dexamethasone-impaired insulin secretion in mice islets. Leonurine ameliorated dexamethasone-induced dephosphorylation of Akt, Bad and GSK-3β. Importantly, the protective role of leonurine on dexamethasone-induced cytotoxicity was blocked by LY294002 in INS-1 cells. Our findings revealed for the first time that leonurine could protect against dexamethasone-induced cytotoxicity in pancreatic β-cells via PI3K/Akt signaling pathway, suggesting leonurine may be a promising therapeutic agent for steroid diabetes.