Butyrate Treatment and Sample Collection

The occurrence of autoimmune responses occurs as early as 6 weeks of age in lupus-prone MRL/lpr female mice (15, 16).To ascertain the effect of butyrate on active disease in MRL/lpr mice, mice were treated with butyrate starting at 8 weeks of age and after disease occurrence to mimic patients with active early-stage lupus. At the age of 8 weeks, female MRL/lpr mice were randomly separated into two groups (n = 6 per group): phosphate-buffered saline (PBS) -treated control group (MRL/lpr) and butyrate-treated group (MRL/lpr + Butyrate). Mice were weighted weekly and treated with sodium butyrate (Sigma-Aldrich, USA; 320 mg/kg, 0.1 mL/10 g body weight) or phosphate-buffered saline (PBS, 0.1 mL/10 g body weight). Treatments were administered three times per week (namely every Monday, Wednesday, and Friday) for 8 weeks by gavage, starting at 8 weeks of age until 16 weeks of age, when subjects were humanely euthanized. After the mice were killed, stool, blood, and kidney tissues were collected for further analysis.