Fig. 8. Exercise via regulating gut microbiota attenuated surgery-induced GDNF decrease and GDNF participated in regulation of immune and inflammatory responses after surgery.

Nine-week old male mice with or without exercise for 4 weeks in the presence or absence of intraperitoneal injection of valeric acid (one injection per week) were subjected to left carotid artery exposure (surgery) under isoflurane anesthesia (panels A and D). In second experiment, 9-week old mice were treated with antibiotics to eliminate their native gut microbiota and then transplanted with feces from control mice (Trans-Control) before the surgery (panel B). In third experiment, 9-week old mice were treated with antibiotics to eliminate their native gut microbiota and then transplanted with feces of exercise mice (Trans-Exe) or control mice (Trans-Control) before the surgery (panel C). In fourth experiment, 9-week old mice received intraperitoneal injection of valeric acid or normal saline (panels E and F). In fifth experiments, 9-week old mice were subjected to surgery and received intracerebroventricular injection of GDNF immediately after surgery (panels G–I). A–D GDNF concentrations in the hippocampus. E Valeric acid in the cerebral cortex. F, G C3 concentrations in the hippocampus. H IL−6 concentrations in the hippocampus. i IL-1β concentrations in the hippocampus. Results in (panels A, B, D and G) are median ± interquartile range with presentation of value of individual mouse and results in other panels are mean ± S.D. with presentation of value of individual mouse (n = 10 for panels A–D and panel F, = 7–8 for panel E, = 12 for panels G–I). Exe exercise, Sur surgery, NS normal saline, Val valeric acid.