Swimming training combined with fecal microbial transplantation protects motor functions in rats with spinal cord injury by improving the intestinal system

Spinal cord injury (SCI) leads to severe intestinal dysfunction and decreased motility. There is an interaction between the intestine and the nervous system, intestinal intervention through microbial regulation and exercise is a potential treatment option for spinal cord injury. We investigated the effects of swimming rehabilitation training combined with fecal microbial transplantation on intestinal as well as neurological functions in rats with spinal cord injuries, and explored the potential mechanisms. The animals were randomly divided into five groups: sham-operated control group (Sham), spinal cord injury only group (SCI), swimming training group (Swimming), fecal microbial transplantation group (FMT) and combined interventions group (Combined). Behavioral assessments, pathological and immunological analyses were performed after the interventions. Compared to rats in the spinal cord injury group, rats subjected to swimming training, fecal microbial transplantation and combined interventions group exhibited improved intestinal transit, barrier functions, motility, and motor conduction pathway conductivity(P < 0.05). The combined interventions group had better outcomes(P < 0.01). In addition, combined interventions significantly suppressed inflammatory factor levels (P < 0.05) in the colon and spinal cords and significantly protected forefoot motor neurons (NeuN) in the spinal cord injury area, inhibiting astrocyte activation and reducing the expressions of the signature glial fibrillary acidic protein (GFAP) and markers of microglia (Iba-1) at the lesion site(P < 0.05). In conclusion, all effects of combined swimming training and fecal microbial transplantation interventions were superior to swimming training or fecal microbial transplantation alone. Swimming training and fecal microbial transplantation interventions have a synergistic effect on the recovery of intestinal function and motility after spinal cord injury. The mechanism of mutual facilitation between gut function and motility may be related to the brain-gut axis interaction.