Hyperuricemia Mouse Model and LPP Treatment

Male Kunming mice (6-week-old, 25 ± 2 g) were purchased from the Chinese Beijing Vital River Laboratory Animal Technology Co., Ltd. All mice were housed in the Animal Center of China CDC Mice with temperature at 24–26°C, humidity at 40–60%, and a 12 h light–dark cycle. Mice had free access to the standard commercial mouse food and water. After one-week adaption, mice were randomly divided into three groups (n = 8/group): negative control group (NC), hyperuricemic group (HUA), and LPP-treated group (LPP). The HUA mouse model was established according to literature with slight modification (18 (link), 21 (link)–26 (link)). Briefly, potassium oxonate (Sigma-Aldrich, MA, United States,) and adenine (Sigma-Aldrich, MA, United States) were suspended in 0.5% Carboxymethylcellulose sodium (CMC-Na) solution. Mice in HUA and LPP groups were daily administered with 0.3 ml solution of potassium oxonate (PO, 250 mg/kg) and adenine (75 mg/kg) by gavage, and NC group mice were given the equal volume of 0.5% CMC-Na solution for 14 days. Four hours after the treatment of PO and adenine, mice in LPP group were orally administered with 1 × 10⁹ CFU LPP in 0.3 ml PBS and mice in NC and HUA groups were given the equal volume of sterile PBS. After 14-day of daily administration of LPP or PBS, mice were sacrificed and body weight was recorded. Blood was collected from the eye vein. To acquire the serum, the collected blood samples were left undisturbed for 30 min then centrifuged at 5000 xg for 20 min. The kidney, liver, ileum, colon, and cecal content were also collected. All samples were stored at −80°C until analysis, except for the samples used for histopathology and RNA sequencing, which were kept in 4% paraformaldehyde and RNAlater (Thermo Fisher Scientific, Waltham, MA, United States) respectively.