2.4 Animals
SD rats weighing 200-250 g (half of which were male) were purchased from the School of Pharmacy, Jilin University (SCXK 2016-0001). All rats were given standard food and water for seven days prior to experimentation and were randomly divided into the blank group (control), intestinal inflammation group (DSS) (Cosin-Roger et al., 2017; M. Zhou et al., 2018), low-dose group of GP treatment (DSS+GP-L, 50mg/kg), middle-dose group of GP treatment (DSS+GP-M, 100mg/kg) and high-dose group of GP treatment (DSS+GP-H, 200mg/kg), each group consisted of 10 rats. Experimental procedures used for the animals and administration methods were based on previously reported experimental protocols (M. Wang, Gao, Xu, & Gao, 2015). The rats fasted for 12 hours on the last day, and each rat was anesthetized and euthanized. The blood from each rat was collected from the common carotid artery. Ten grams of fresh feces from the rats in each group were collected and weighed in a sterilized beaker, and 50 ml of 37 °C sterile normal saline was added, stirred, and filtered with double-layer sterile gauze. The filtrate was then centrifugated at 6,000 g / min for 15 min (centrifugation radius: 10 cm), and then the sediment was suspended in 100 ml of normal saline to obtain the fecal bacteria solution. FMT (5 ml / kg) was administered by gavage once a day for 14 days. The distal parts of the colon tissues were stored in a -80 °C refrigerator for section or Western blot analysis. Feces were collected for further metabolite analysis. Blood was centrifuged, and the supernatant was stored at -20 °C for later testing. The relative serum levels of IL-1β, IL-6 and TNF-α were determined using ELISA kits (Beyotime Institute of Biotechnology, Shanghai, China) according to the manufacturer’s instructions.