TSPO and Sepsis: At 10 days after sepsis, spleen weight had negative correlation with butyrate levels (Fig. 10J; r = − 0.7041, p = 0.023, R2 = 0.4958), probe trail (r = − 0.5281, p = 0.0430, R2 = 0.2789, data not shown) and positive correlation with TSPO expression in the PFC (Fig. 10K; r = 0.8855, p = 0.0003, R2 = 0.7490) and hippocampus (Fig. 10L; r = 0.7413, p = 0.0058, R2 = 0.549).