Effect of spinal cord stimulation in a rodent model of post-operative ileus

Post-operative ileus (POI) is a transient impairment of gastrointestinal (GI) transit that develops after abdominal surgery. The goal of this study was to investigate the effect of spinal cord stimulation (SCS) on gastric emptying and upper GI transit in a rat model of POI. All rats had an electrode placed on the dorsal surface of the spinal cord between the T(5) and T(8) segments. After recovery, gastric emptying and upper GI transit (geometric centre and head of meal) were assessed using a radiolabelled meal fed to each rat via oral gavage. In unanaesthetized rats, SCS (15, 25, 50, 100, 200 Hz, 0.2 ms at 90% motor threshold for 15 min) was performed immediately after the meal. The sham control group had no current applied. The naïve group was without POI or SCS. Gastric emptying was significantly delayed in sham-stimulated rats with POI compared with naïve controls (39.8 +/- 6.2%vs 76.5 +/- 4.9%, P < 0.001). In rats with POI that underwent SCS, there was a significant acceleration of gastric emptying to levels that resembled those of naïve controls (65.1 +/- 7.4%, P < 0.05). However, while SCS did not normalize the geometric centre and head of the meal when compared with the naïve group, it did significantly improve both parameters compared with the sham stimulation group. In summary, SCS normalizes gastric emptying and improves upper GI transit in a rodent model of POI. Further experiments are required to address the mechanism(s) by which SCS exhibits prokinetic activity.