Withaferin-A attenuates multiple low doses of Streptozotocin (MLD-STZ) induced type 1 diabetes

Abstract

Type 1 diabetes mellitus (T1DM) is one of the major metabolic disorders with life-long dependence on insulin. The present study was designed to evaluate the antioxidant and anti-diabetic potential of Withaferin A (WA), the active constituent of Withania somnifera in multiple low doses of Streptozotocin (MLD-STZ) induced T1DM. STZ (40 mg/Kg) was administered intraperitoneally (i.p.) for 5 consecutive days to male Swiss albino mice to induce T1DM. Mice were concurrently treated with WA (2 & 10 mg/Kg). Blood glucose levels, intraperitoneal glucose tolerance test, oxidative stress parameters were estimated biochemically (MDA, GSH) and immunohistochemically (Nrf2, NFκB). In addition, inflammatory cytokines, and insulin levels were quantified by ELISA method. Apoptosis was assessed by immunohistochemical staining for cleaved-caspase-3 and TUNEL assay. WA treatment significantly reduced the blood glucose levels and improved glucose clearance. Strikingly, we observed a significant reduction in the incidence of diabetes upon WA treatment and only 2 out of 8 (2/8 = 25%) animals were diabetic. WA ameliorated the MLD-STZ induced oxidative and nitrosative stress. Furthermore, WA exhibited promising anti-inflammatory effect as evident from reduction in the levels of IL-6 (p < 0.05) and TNF-α (p < 0.05) compared to diabetic mice. In addition, insulitis scoring and IHC for Nrf2 and NFκB indicated promising anti-diabetic effect. WA reduced MLD-STZ induced DNA fragmentation and apoptosis, further supporting the observed protective effect. We, to the best of our knowledge, report for the first time that WA can effectively combat MLD-STZ induced T1DM via modulation of Nrf2/NFκB signaling and holds substantial potential for therapy of T1DM.