Anti-diabetic effect of ramulus mori polysaccharides, isolated from Morus alba L., on STZ-diabetic mice through blocking inflammatory response and attenuating oxidative stress

Diabetes mellitus is a clinically complex disease characterized by the dysfunctions of pancreas. In this study, we investigated the therapeutic effects of ramulus mori polysaccharides (RMP) on diabetic mice induced by streptozotocin. Our results showed that body weight and insulin level were notably increased after metformin and RMP treatments, while the blood glucose was lowered. HE-staining assay showed that the treatments mitigated the pathological lesions in pancreas tissue. In addition, the expression levels of tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), interleukin-6 (IL-6) and cyclo-oxygenase-2 (COX-2) were effectively reduced in pancreas tissue by the treatments, respectively. We also found that upon these treatments, the activities of manganese superoxide dismutase (MnSOD) and glutathione reductase (GSH-Rd) were increased; the content of malonaldehyde (MDA) was decreased in pancreas tissue; and the mRNA expression of heme oxygenase-1 (HO-1) was markedly increased in pancreas tissue. Taken together, these results suggest that RMP plays the blood glucose-lowering and metabolism-normalizing roles, and it may improve the function of pancreas through inhibiting the inflammatory response and attenuating the oxidative stress in pancreas tissue.