Animal experiments
Male KM mice (7-8 weeks, 18-22 g, RRID:MGI:5651867) were purchased from the Laboratory Animal Centre of Sun Yat-sen University (Guangzhou, China) and male Zucker Diabetic Fatty (ZDF) rats including ZDF-Leprfa/fa rats and ZDF-Leprfa/ctrl rats (7-8 weeks, 220~240 g, RRID:RGD_2314027, RRID:RGD_2311071) were purchased from Beijing Vital River Laboratory Animal Technology (Beijing, China). All animal procedures were approved by the Sun Yat-sen University Committee on Ethics for the Use of Laboratory Animals in accordance with the Animal Welfare Legislation of China. Animal studies are reported in compliance with the ARRIVE guidelines.
KM mice were kept at 22 ± 1 °C on a 12-hour light/dark cycle with free access to food and water. These mice were randomly divided into 6 groups, including lean group (without glucose administrated), vehicle group, metformin group, Dapagliflozin group, AST group andCAG group, each group included 10 mice. Metformin (100 mg/kg), Dapagliflozin (1 mg/kg), AST (5 mg/kg), CAG (5 mg/kg) were dissolved in normal saline containing 1% CMC-Na and taken gavage administration in mice. The lean and the vehicle groups were administered the same volume. After acclimatization, oral glucose tolerance test (OGTT) was performed. Briefly, mice were fasted for a period of 14 h and then administrated with glucose (2 g/kg) orally. The plasma glucose of 0, 15, 30, 60, and 120 min were detected by using a blood glucose meter (Roche), respectively.
ZDF-Leprfa/ctrl rats were fed a chow diet provided by the Animal Center of Sun Yat-sen University and ZDF-Leprfa/fa rats were fed high fat diet 5008 (Labdiet, USA) for one month. Randomly selected the rats with blood glucose over 11.1 mmol/L from ZDF-Leprfa/fa rats before experiments. These ZDF rats were divided into 5 subgroups: lean group (ZDF-Leprfa/ctrl, saline), vehicle group (ZDF-Leprfa/fa, model), Dapagliflozin (1 mg/kg/d,p.o. ), CAG (1 and 5 mg/kg/d, p.o. ). The OGTT experiment was preceded after the administration of CAG as described above. The urinary glucose, urinary sodium, and urine efflux were determined after 1- or 5-week treatment, respectively.