ABSTRACT
Objective:To investigate the effects of Daizongfang （DZF） on insulin resistance （IR） of adipocytes induced by different methods. Method:The cocktail induction method was adopted to induce the differentiation and maturity of 3T3-L1 preadipocytes. An IR model in mature adipocytes was established by the induction of palmitic acid （PA）， high-concentration glucose （HG）， and dexamethasone （DEX）. DZF extracts at different concentrations （2.0， 0.5， 0.1 g·L<sup>-1</sup>） intervened for 24 hours. A model group， a rosiglitazone （RSG） group， and a blank control group were set up at the same time. The glucose concentration in the culture supernatant was measured by the glucose oxidase-peroxidase （GOD-POD） method. Glucose consumptions under basic conditions （G<sub>Basic</sub>） and insulin stimulation （G<sub>Ins</sub>） were calculated to evaluate the insulin sensitivity index （ISI）. The mRNA expression of glucose transporter 4 （GLUT4） was detected by the real-time polymerase chain reaction （PCR）. Result:Compared with the model group， the DZF （2.0 g·L<sup>-1</sup>） showed increased G<sub>Basic</sub>， G<sub>Ins</sub>， and ISI in three IR models （<italic>P</italic><0.05， <italic>P</italic><0.01）. In addition， for the PA-induced IR model， G<sub>Basic</sub> and G<sub>Ins</sub> in the DZF （0.5 g·L<sup>-1</sup>） group were elevated （<italic>P</italic><0.01）， and G<sub>Basic</sub>， G<sub>Ins</sub>， and ISI in the RSG group increased （<italic>P</italic><0.05， <italic>P</italic><0.01）. For the HG-induced IR model， G<sub>Ins</sub> and ISI increased in the DZF （0.5 g·L<sup>-1</sup>） group （<italic>P</italic><0.05）， and G<sub>Basic</sub>， G<sub>Ins</sub>， and ISI were elevated in the RSG group （<italic>P</italic><0.01）. For the DEX-induced IR model， G<sub>Ins</sub> and ISI increased in the RSG group （<italic>P</italic><0.01）. In the three models， there were differences among groups with different doses. G<sub>Basic</sub>， G<sub>Ins</sub>， and ISI in the high-dose DZF group increased in varying degrees compared with those in the medium- and low-dose DZF groups （<italic>P</italic><0.05）. In the three models， the DZF （2.0 g·L<sup>-1</sup>） group and the RSG group both increased GLUT4 mRNA expression （<italic>P</italic><0.05）. Conclusion:DZF can reduce IR of adipocytes induced by HG， DEX， or PA in a dose-dependent manner and increase glucose uptake in an insulin-independent manner， which may be related to the increase in GLUT4 expression.