Abstract: Objective To study the effect of total flavonoids (TF) of Melastoma dodecandrum on insulin resistance and renal damage in rats with diabetic nephropathy (DN). Methods Ten of 60 rats were randomly selected as normal group, and the remaining 50 rats were intraperitoneally injected with streptozotocin to establish the DN model and finally 43 DN models were successfully established. The 40 rats with DN were selected and randomly divided into four groups (n = 10 each), including DN model group, low-dose TF [150 mg / (kg·d)] group, middle-dose TF [300 mg / (kg·d)] group and high-dose TF [600 mg / ( kg·d)] group. On the 2nd day after the establishment of the rat DN models, the animals in TF-treated groups were given TF at different doses by gavage, and those in control group and model group were given the same volume of normal saline. The treatments lasted 30 d, and then renal tissues were removed for pathological analysis. The laboratory indicators including fasting plasma glucose (FPG), fasting insulin (FINS), serum creatinine (Scr), blood urea nitrogen (BUN), uric acid (UA) and microalbumin ( mAlb) were determined. The insulin resistance index (HOMA-IR) and the sensitivity index (ISI) were calculated. Results The levels of FPG, FINS, Scr, BUN, UA and mAlb in DN model group were significantly higher than those in control group (P< 0. 05). The FPG, FINS and HOMA-IR were significantly reduced (P < 0. 05) while ISI was significantly increased in TF-treated groups as compared with those in DN model group (P < 0. 05), and the changes of HOMA-IR and ISI were increased significantly with the increase of TF dose (P < 0. 05). The levels of Scr, BUN, UA and mAlb were significantly lowered in a dose dependent manner in TF-treated groups compared to those in DN model group (P < 0. 05). Conclusion TF of Melastoma dodecandrum can effectively improve the IR, decrease the blood glucose, alleviate the pathological damage of renal tissues and promote the recovery of renal function of DN rats.

Key words: diabetic nephropathy, rats, insulin resistance, renal function, total flavonoids of Melastoma dodecandrum