Abstract:Objective To investigate the effects of curcumin on glucose transport and phosphatidylinositol 3-kinase (PI3K) / protein kinase B (Akt) signaling pathway in adipocytes of type 2 diabetes mellitus (T2DM) rats. MethodsNinety Sprague-Dawley (SD) rats were randomly divided into normal group, model group (high-fat diet-fed), curcuminlow-dose group (50 mg/ kg), curcumin medium-dose group (150 mg/ kg), and curcumin high-dose group (250 mg/ kg)groups, and rosiglitazone group (1. 35 mg/ kg), each group comprised 15 rats. The body weight of rats was measuredimmediately after administration, 2 weeks after administration and 8 weeks after administration, and blood was collected for12 hours after fasting at the end of 8 weeks, fasting blood glucose (FBG), fasting insulin (FINS), the insulin resistanceindex (HOMA-IR), triglyceride (TG), low/ high-density lipoprotein cholesterol (LDC-C/ HDL-C), and total cholesterol(TC) were measured. The glucose perfusion rate was measured by positive glucose clamp assay, the translocation of glucosetransporter 4 (GluT4) in adipocyte membrane was detected by fluorescence immunoassay,GluT4 in adipocytes was detectedby real-time fluorescence quantitative PCR (qRT-PCR), the expression of GluT4, p-PI3K, insulin receptor substrate 2(Irs2) and p-Akt in intracellular and extracellular membranes of adipocytes were detected by Western blotting. Results Compared with the normal group, the weight of the model group increased immediately and 2 weeks after administration,and decreased 8 weeks after administration; compared with the model group, the body weight of curcumin treatment groupand rosiglitazone treatment group decreased immediately, 2 weeks and 8 weeks after administration ( P < 0. 05). Comparedwith the normal group, the FBG, FINS, HOMA-IR, HDC-L, LDC-L, TC and TG in the model group increased, and theglucose injection rate decreased in a dose-dependent manner; GluT4 mRNA increased in the model group, the proteinexpression of GluT4, Irs2, p-PI3K/ PI3K and pAkt/ Akt decreased significantly; and the differences were statisticallysignificant ( P < 0. 05). Compared with the model group, the levels of FBG, FINS, HOMA-IR, HDC-L, LDC-L, TC and TGin the curcumin treatment group and rosiglitazone group were significantly lower, the rate of glucose injection was significantlyhigher, GluT4 mRNA decreased, the protein expression of GluT4, Irs2, p-PI3K/ PI3K and pAkt/ Akt increased significantly,and the differences were statistically significant ( P < 0. 05), and the difference of curcumin dosage among the three groupswas also statistically significant ( P < 0. 05). Conclusions Curcumin can increase the insulin sensitivity of T2DM rats,which may be achieved by activating PI3K/ Akt signaling pathway to promote the GluT4 membrane translocation in adipocytesand increase the uptake of glucose by adipocytes, thereby alleviating the balance of blood sugar metabolism.