[The optimization and assessment of the method for inducing hyperuricemia in rats]

Objective: To explore an effective method for inducing a rat model with hyperuricemia in a short period and assess the effects of the model. Methods: Sprague-Dawley rats were adopted as donors and randomly divided into control group (CT group, n=6) and 5 model groups (M1-M5 groups, n=8 in each group). M1 group (gavage with 10 g/kg yeast extracts and 100 mg/kg adenine, twice per day, 300 mg/kg oxonic acid potassium by intraperitoneal injection, in the 7^th day of model inducing), M2 group (gavage with 10 g/kg yeast extracts and 100 mg/kg adenine, twice per day, 300 mg/kg oxonic acid potassium by intraperitoneal injection, in the 1^st, 3^rd and 7^th day of model inducing),M3 group (gavage with 10 g/kg yeast extracts and 100 mg/kg adenine, twice per day, 300 mg/kg oxonic acid potassium by intraperitoneal injection, once per day during the model inducing), M4 group (gavage with 20 g/kg yeast extracts and 100 mg/kg adenine, twice per day, 300 mg/kg oxonic acid potassium by intraperitoneal injection, once per day during the model inducing), M5 group (gavage with 30 g/kg yeast extracts and 100 mg/kg adenine, twice per day, 300 mg/kg oxonic acid potassium by intraperitoneal injection, once per day during the model inducing), and group CT (gavaged with equal volume sterilized water and intraperitoneal injected with normal saline according to the weight and at the same frequency as the model groups). The model inducing lasted for 7 days. After the inducing was finished, blood and 24-hour urine were sampled for uric acid and creatinine determination. Then rats were maintained for 2 weeks and blood and 24-hour urine samples were collected, the concentration of uric acid and creatinine were detected. The kidney and stomach were weighed,morphological changes in kidney were observed. Results: After model inducing, the body weight of rats in all model groups was lower than that of the control group (P＜0.01). Deaths occurred in all the rats with model treatments except M2. M4 and M5 groups were failed to be analyzed because of the high mortality, model 1 and 3 groups had 4 and 2 deaths, respectively. The uric acid levels in blood and urine of the model groups were significantly elevated (P＜ 0.01) at the end of model inducing. The model 2 group's blood uric acid was highest among the model groups (P＜0.05). It sustained a higher concentration than CT group in the three model groups after 2 weeks feeding (P＜0.05). The kidneys in model groups obviously swelling and were heavier than CT group (P＜0.01). The inflammation and structural damages were observed in kidneys of all model groups.Conclusion: The yeast extract (10 g/kg), adenine (100 mg/kg) gavage combined with intraperitoneal injections(the 1^st, 3^rd, 7^th day during inducing) of potassium oxonate can be an rapid and effective method for inducing the rat model with hyperuricemia, which can be suggested to the related research.