Study design and experimental groups. In part 1, STZ was injected once per day to induce DM. LBP was administered by oral gavage daily for 12 weeks. In part 2, STZ was injected once per day to induce DM. LBP and/or Fasudil were respectively administered by oral gavage and intraperitoneal injection daily for 12 weeks. In part 3, different level of glucose or 1 g/L LBP + glucose were added in medium of RF/6A cell. All animals and tissues were measured at 4, 8 and 12 weeks after LBP and/or Fasudil administration. Cells were measured at 3, 5 and 7 days after seeding in different level of glucose or 1 g/L LBP + glucose. STZ, streptozotocin; I.P, intraperitoneal; I.G, intragastric administration; WB, Western blot; IHC, Immunohistochemistry.