Nardostachys jatamansi extract protects against cytokineinduced β-cell damage and streptozotocin-induced diabetes

AIM: To investigate the anti-diabetogenic mechanism of Nardostachys jatamansi extract (NJE). METHODS: Mice were injected with streptozotocin via a tail vein to induce diabetes. Rat insulinoma RINm5F cells and isolated rat islets were treated with interleukin- 1β and interferon-γ to induce cytotoxicity. RESULTS: Treatment of mice with streptozotocin resulted in hyperglycemia and hypoinsulinemia, which was confirmed by immunohistochemical staining of the islets. The diabetogenic effects of streptozotocin were completely abolished when mice were pretreated with NJE. Inhibition of streptozotocin-induced hyperglycemia by NJE was mediated by suppression of nuclear factor (NF)-κB activation. In addition, NJE protected against cytokine-mediated cytotoxicity. Incubation of RINm5F cells and islets with NJE resulted in a significant reduction in cytokine-induced NF-κB activation and downstream events, inducible nitric oxide synthase expression and nitric oxide production. The protective effect of NJE was further demonstrated by the normal insulin secretion of cytokine-treated islets in response to glucose. CONCLUSION: NJE provided resistance to pancreatic β-cell damage from cytokine or streptozotocin treatment. The β-cell protective effect of NJE is mediated by suppressing NF-κB activation.