Time‐course of recovery of gastric emptying and motility in rats with experimental spinal cord injury

Abstract

We have shown recently that spinal cord injury (SCI) decreases basal gastric contractions 3 days after injury. In the present study we used the [13C] octanoic acid breath test as well as gastric strain gauges with the aim to investigate the time-course of recovery from post-injury gastric stasis in rats that underwent experimental SCI at the level of the third thoracic (T3) vertebra. Following verification of the [13C]-breath test sensitivity in uninjured rats, we conducted our experiments in rats that underwent T3- spinal contusion injury (T3-CI), T3- spinal transection (T3-TX) or laminectomy (control) surgery at three days, one, three or six weeks post-injury. Our data show that compared to rats that underwent laminectomy, rats that received SCI showed a significant reduction in the cumulative percent [13C] recovery. Although more marked in T3-TX rats, the delayed gastric emptying in T3-CI and T3-TX rats was comparable in the 3 days-three weeks period post-injury. At six weeks post-injury, the gastric emptying in T3-CI rats recovered to baseline values. Conversely animals in the T3-TX group still show a significantly reduced gastric emptying. Interestingly, the almost complete functional recovery observed in T3- CI rats using the [13C]-breath test was not reflected by analysis of spontaneous gastric contractions after SCI. These data indicate that T3-SCI produces a significant reduction in gastric emptying independent of injury severity (T3-CI vs. T3-TX) that persists for at least 3 weeks after injury. However, 6 weeks post-injury T3-CI, but not T3-TX, rats begin to demonstrate functional recovery of gastric emptying.

Experimental spinal cord injury in rats diminishes vagally-mediated gastric responses to cholecystokinin-8s

“…We and others have shown recently that models of experimental high-thoracic spinal cord injury (T3-SCI) mirror the GI clinical presentation of neurotrauma patients, indeed we reported that T3-SCI animals show a diminished food intake and gastroparesis 28,29, while other groups have also shown inhibition of gastric emptying and duodenal transit of liquids 30-33. We have also shown a significant reduction in gastric motility and a diminished esophageal-gastric relaxation reflex in anesthetized T3-SCI rats 3 days after injury 28.…”

Gastric emptying of enterally administered liquid meal in conscious rats and during sustained anaesthesia

“…Unfortunately, gastric half emptying time was not reported by those authors, thus limiting further comparisons. In our previous [ 13 C]-breath test study30 we reported T max and T 1/2 values for gastric emptying in surgically naïve animals fed a solid meal that contained the same molar amount of [ 13 C]-octanoic acid. Similarly to our observations of liquid gastric emptying, the sensitivity of our [ 13 C]-breath test for solid emptying was also in general agreement with published reports27.…”

“…Rats were gavaged with 1ml Ensure® in the days prior to the experiment in order to establish familiarity to the technique and the meal. Following an overnight fast (water ad libitum), the [ 13 C]-breath test was performed using procedures described previously30. Briefly, animals were placed in a 7 L capacity metabolic chamber with a continuous flow of fresh air (0.65 l/min) in order to maintain CO 2 levels near 0.5%.…”

Autonomic Consequences of Spinal Cord Injury

“…Functional recovery of gastric emptying is established at 6 weeks post T3 contusion. However, it does not occur in animals with spinal cord transection (278). The recovery of gastric emptying after contusion SCI may correlate with plasticity of vagal and enteric neurocircuitry.…”