Structural changes in gastric glial cells and delayed gastric emptying as responses to early life stress and acute adulthood stress in rats

AimEnteric glial cells (EGCs) modulate colonic motility in a maternal separation model. We aimed to investigate structural changes in gastric EGC and gastric emptying as responses to maternal separation and acute adulthood stress in rats to elucidate the pathophysiological roles of gastric EGC.Main methodsAs a chronic stress, we subjected male Wistar rats to 3 h of maternal separation during postnatal days 2–14. As an acute adulthood stress (7 weeks of age), we used the 8-h water-immersion method. We morphologically evaluated gastric EGCs using whole-mount longitudinal muscle-myenteric plexus preparations. We analyzed gastric emptying by the phenol red method.Key findingThe area of EGC processes that apparently overlapped with neurons increased according to stress intensity (acute stress, 10.4%; maternal separation, 10.2%; maternal separation plus acute stress, 26.6%; control, 5.0%). Ratios of morphologically changed leaf-like processes to the total processes were 8.1%, acute stress; 10.3%, maternal separation; 4.0%, control. Ratio dramatically increased in the combined stress group (20.5%, p = 0.026 vs. control). The mean bulging head area of leaf-like processes in the combined stress group was greater by 6.4 μm2 (control, 2.4 μm2; p = 0.042). Gastric emptying in the maternal separation group was gradually delayed (104.1% at 7 weeks, 66.7% at 17 weeks, and 48.5% at 48 weeks; p < 0.05, respectively). Gastric emptying in the combined stress group tended to be delayed at 17 weeks (45.7% vs. 81% in controls, p = 0.066).SignificanceGastric EGCs exhibited structural changes according to stress intensity, which may be associated with stress-induced dysfunction of the stomach.