Pilot Study: Gut Function Following Experimental Cervical Spinal Cord Injury

Spinal cord injury (SCI) has been linked to diminished gut function, with patients citing a return to normal bowel function as a high priority. Prior studies using a left C2 hemisection (LC2Hx) model have shown microscopic pathological changes that are reversed with probiotic (pbx) administration. This study aimed to identify macroscopic functional changes following a LC2Hx, and if probiotic administration can improve functional recovery. We hypothesized there would be slowed gut transit following LC2Hx that improved with probiotics administration. We completed two experiments, each with six female Springer-Dawley rats, over a two week timeline. We split the first cohort into naive and LC2Hx groups and the second cohort into LC2Hx gavaged with saline and LC2Hx gavaged with pbx groups. The second cohort received daily gavage. Fecal pellets were collected over 14 days, weighed, dried for 24 hours, then re-weighed to measure the fecal water content. Rats were also housed individually for 24 hours to measure the total fecal output. Once euthanized, the colons were weighed and measured to calculate the colon weight-to-length ratio – a macroscopic marker correlated with colon histopathologic scores. In the first cohort, the LC2Hx rats produced fewer fecal pellets and had lower fecal water content at 2 weeks post-injury compared to the naive rats. Furthermore, the colon weight-to-length ratio was higher in the LC2Hx group. There was no difference in fecal water content between the pbx and saline groups in the second cohort, but the pbx group returned to pre-injury levels of pellet production at 2 weeks, while the saline group remained low. The colon weight-to-length ratio was significantly lower in the pbx group than the saline group. Both the decreased pellet production and fecal water content in the LC2Hx groups of both cohorts are consistent with decreased gut motility and subsequent constipation post-SCI. Gut inflammation increased following SCI, as evidenced by the increased colon weight-to-length ratio in the LC2Hx groups. Prior studies have shown an increased Firmicutes/Bacteroidetes ratio - an indicator of gut dysbiosis, namely an imbalance of pathogenic to commensal bacteria - which could explain this finding of increased colon inflammation. The return to normal fecal pellet production and a decrease in colon weight-to-length ratio in the pbx group suggests treating this gut dysbiosis with probiotics mitigates gut inflammation, leading to improved gut function. This study shows evidence of gut dysfunction in a cervical model, with promising results of probiotics as a possible treatment. Studies are ongoing to verify these results. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.