Sprague dawley rats

A total of 50 male Sprague-Dawley rats (weight, 250±20 g; age, 8 weeks old) were purchased from the Shanghai Laboratory Animal Center (Shanghai, China) and housed in 40×50×25 cm cages at room temperature (25±1°C) with ad libitum access to food and water. The animals were housed in groups of 5–6 rats with a 12-h light/dark cycle. All animal experiments were performed in accordance with the regulations of the State Science and Technology Commission for the Care and Use of Laboratory Animals (no. 2, 1988). The present study was approved by the Ethics Committee of Zhejiang Chinese Medical University (Hangzhou, China).

Ten-week-old male Sprague-Dawley rats were purchased from Shanghai Laboratory Animal Center. Rats were housed under optimal conditions with standard hygiene, kept at a temperature of 25 °C with a 12/12 light/dark cycle, fed with standard rat chow and water ad libitum. The experiments were performed in accordance with the National Institutes of Health Guidelines for the Use of Laboratory Animals (NIH, publication number 85-23, revised 1996.), which were approved and performed according to guidelines for the care and use of animals established by Soochow University.

Inbred male Sprague Dawley rats (200 ± 20 g) were purchased from Shanghai Experimental Animal Center, Chinese Academy of Sciences. The rats were housed in an air-conditioned room at 25°C with a 12-h darkness/light cycle. The rats received humane care with unlimited accesses to food and water during the study. All of the study's protocols comply with the current ethical considerations of Shanghai University of Traditional Chinese Medicine's (TCMs) Animal Ethic Committee.

A total of 25 5-6 week old male Sprague-Dawley rats were purchased from Shanghai Laboratory Animal Center (Shanghai, China). Rats were fed a normal diet with water ad libitum prior to treatment administration and kept under a 12 h light/dark cycle in a controlled environment (temperature, 22±2°C; humidity 60-80%). All protocols, including diabetes induction and animal sacrifice, were approved by the Institutional Animal Care and Use Committee of the First Hospital of Jilin University (Changchun, China), and the China Council on Animal Care. The rats received adaptive feeding.
Rats in DN group (n=15) were administered an intra-peritoneal injection of streptozotocin (55 mg/kg), while rats in the control group (n=10) received only citrate buffer. Biochemical kits (Xibao Biotechnology Co., Ltd., Shanghai, China) were used to measure the blood glucose levels at 24, 48 and 72 h after streptozotocin injection. After 72 h of assessment, blood was collected from the tail vein of rats and fasting blood glucose was determined. Rats with fasting blood glucose levels of >250 mg/dl were considered as diabetic. The levels of blood urea nitrogen (BUN) and serum creatinine (SCr) in rats were detected by enzyme-linked immunosorbent assay (ELISA), and the corresponding kits were purchased from Wuhan Huamei Biotech Co., Ltd. (Wuhan, China).