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Stress–strain analysis of duodenal contractility in response to flow and ramp distension in rabbits fed low‐fiber diet
Author(s) -
Liu Yue,
Zhao Jingbo,
Liao Donghua,
Wang Guixue,
Gregersen Hans
Publication year - 2019
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/nmo.13476
Subject(s) - distension , contractility , strain (injury) , stress (linguistics) , medicine , fiber , cardiology , endocrinology , materials science , composite material , philosophy , linguistics
Background Previously we demonstrated that low‐fiber diet in rabbits affects the passive mechanomorphological properties in the small intestine, resulting in reduced intestinal wall thickness and collagen content, as well as intestinal wall softening. The aim of the present study was to evaluate the contractility in rabbits on long‐term low‐fiber diet and specifically to compare the contraction threshold, the frequency, and the amplitude of flow‐induced and distension‐induced contractions in the duodenum between rabbits on normal diet and on long‐term low‐fiber diet. Methods Ten rabbits were fed a low‐fiber diet for 5 months (Intervention group), and five rabbits were fed normal diet (Control group). The duodenal segments were used for determination of mechanical parameters for analyses of contractility. The duodenal experiments were carried out in organ baths containing physiological Krebs solution. Pressure and diameter changes induced by contractions in response to flow and ramp distension were measured. The frequencies and amplitude of contractions were analyzed. Distension‐induced contraction thresholds and maximum contraction amplitude of flow‐induced contractions were calculated in terms of mechanical stress and strain. Multiple linear regression analyses were applied to study dependencies between contractility parameters and wall thickness, wall area, and muscle layer thickness. Key results During distension, the pressure, stress, and strain thresholds for induction of phasic contraction were biggest in the Intervention Group ( P < 0.05). In addition, the contraction frequencies during flow‐induced contraction were highest in the Intervention Group ( P < 0.05), whereas the maximum contraction amplitudes in terms of pressure, diameter, stress, and strain were lowest in the Intervention Group ( P < 0.05). The contraction thresholds and contraction frequencies were negatively associated with the wall thickness, wall area, and muscle layer thickness, whereas maximum contraction amplitudes were positively associated with the wall thickness, wall area, and muscle layer thickness. Conclusions and inferences Duodenal contractility in rabbits fed with long‐term low‐fiber diet exhibited low contraction amplitudes and high contraction thresholds and frequencies. The changes were associated with the low‐fiber diet‐induced histomorphological remodeling. Studies on detailed structural and functional diet‐induced changes in smooth muscle and intestinal nerves are needed for better understanding the remodeling mechanisms.