Morphological alterations in gastrointestinal organs of western-diet obese rats submitted to vertical sleeve gastrectomy or Roux-en-Y gastric bypass

Abstract

To assess the effect of vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) on the esophageal and intestinal morphology of western diet (WD)-obese rats and to characterize the stomach histopathology of WD rats submitted to VSG. Male Wistar rats received WD from 2-4 months of age, to induce obesity, before randomly submitting them to pseudo (WD-SHAM), VSG (WD-VSG) or RYGB (WD-RYGB) surgeries.Gastrointestinal histomorphometry was performed at 3-months post-surgery. The upper esophagus of VSG and RYGB rats increased luminal area, while reductions in the keratin layer of the mucosa and the tunica muscularis were observed only in the RYGB animals. In the lower esophagus, both surgeries increased keratin layer thickness, but reduced the mucosal mucus content, while RYGB increased the thickness of the tunica mucosa and muscularis. The glandular region of the stomach of WD-VSG rats exhibited hypotrophy, epithelial erosion, fi brosis and moderate infl ammatory infi ltration. VSG and RYGB increased the villi height in the ileum, and the thickness of the tunica muscularis in the jejunum and ileum of WD rats; furthermore, RYGB augmented the ileal villi height.Thus both approaches induced histomorphological alterations in the esophagus and intestine and VSG damaged the gastric mucosa, even over the long-term.

RYGB surgery has modest effects on intestinal morphology and gut hormone populations in the bypassed biliopancreatic limb but causes reciprocal changes in GLP-2 and PYY in the alimentary limb

“…In this small pilot study, RYGB was associated with relatively minor changes in intestinal morphology in rats, which were nevertheless greater in the AL than in the bypassed BPL. We observed decreased crypt depth and increased villi width in the AL of HFD-RYGB rats, with no change in villi length, in good agreement with others [ 12 , 17 ]. This may indicate villi hypertrophy, a hallmark of mucosal adaptation, in response to increased nutrient stimulation [ 13 ].…”

“…However, there is a scarcity of information regarding whether such RYGB induced effects directly correspond to alterations of the morphology and gut hormone cell population within both the BPL and AL. We employed female rats for the current investigations to ensure lack of sex-dependent effects, since most studies to date assessing effects of RYGB on intestinal morphology have employed male rodents [12][13][14].…”