Experimental model of hyperuricemia in mice and drug administration

The hyperuricemic animal model was established by injecting the animals with PO, a urate oxidase inhibitor [16, 17]. PO were administrated according to previously described method [18], with modifications. Briefly, the mice were divided into six groups of five mice each, and ChondroT was orally pre-administered at doses of 37.5, 75, and 150 mg/kg/day for 7 days before the PO administration. And then, all the mice except those in the normal control group were intraperitoneally injected once daily with PO (300 mg/kg) at 10:00 a.m. for 7 days experiment. The PO was dissolved in 0.9% saline solution before use. ChondroT (37.5, 75, and 150 mg/kg) and AP (5 mg/kg) were orally administration at 11:00 a.m. for 7 consecutive days on the day when the PO was given. Two hours after the final drug administration, all animals were anesthetized using 2.5% isoflurane. Blood samples were collected from the abdominal aorta of the mice and then the samples were centrifuged at 3000 g for 10 min. The supernatant serum and urine samples were both collected and stored at − 20 °C until they were assayed. The mouse kidneys and livers were collected, washed with 0.9% cold saline solution, and stored at − 80 °C until they were assayed.