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Bao L, Zhao J, Gregersen H. Association between jejunal remodeling in fasting rats and hypersensitivity of intestinal afferent nerves to mechanical stimulation. Biomech Model Mechanobiol 2024; 23:73-86. [PMID: 37548873 DOI: 10.1007/s10237-023-01758-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 07/24/2023] [Indexed: 08/08/2023]
Abstract
Remodeling of Intestinal properties and hypersensitivity of intestinal afferents to mechanical stimulation were previously demonstrated in a fasting rat model. Other studies investigated the association between mechanical and histological remodeling during fasting. This study aimed to further explore the relationship between the jejunal remodeling and intestinal afferent hypersensitivity by combining afferent nerve recordings with histological and mechanical data. Eight male Sprague Dawley rats had no access to food for 7 days (Fasting group). Seven male rats served as controls (Control group). Jejunal segments were studied in vitro in an organ bath for analysis of afferent signaling and for analysis of mechanical and histomorphological parameters. Correlation analyses were done to analyze association between nerve activity (spike rate increase ratio, SRIR) at distension levels of 20, 40 and 80 cmH2O and mechanical stress and histomorphological changes of the jejunal segments. Compared with the Control group, the main findings in jejunal segments in the Fasting group were (1) Most histomorphometry parameters were reduced (P < 0.05-P < 0.001), (2) SRIR values were higher (P < 0.001), (3) The relative numbers of intermuscular and submucosal neurons were increased (P < 0.05-P < 0.01), and (4) SRIR was negatively correlated with intestinal wall thickness, circumferential muscle layer thickness and positively correlated with the inner residual strain, the number of neurons, and the mechanical stress. In conclusion, the fasting-induced histomorphological remodeling (reduced wall thickness and increased relative number of neurons) and biomechanical remodeling (residual strain changes and high stress level) of the intestine in fasting rats were associated with hypersensitivity of intestinal afferents. Afferent hypersensitivity appears to be dependent on stress rather than on strain.
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Affiliation(s)
- Lingxia Bao
- Chongqing University of Posts and Telecommunications, Chongqing, 400065, China
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China
| | - Jingbo Zhao
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China.
- Anbiping (Chongqing) Pathological Diagnosis Center, No. 8 Xiyuan North Road, Shapingba District, Chongqing, 401334, China.
| | - Hans Gregersen
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China
- GIOME, California Medical Innovations Institute, San Diego, CA, USA
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Bao L, Zhao J, Liao D, Wang G, Gregersen H. Pressure overload changes mesenteric afferent nerve responses in a stress-dependent way in a fasting rat model. Biomech Model Mechanobiol 2020; 19:1741-1753. [PMID: 32072371 DOI: 10.1007/s10237-020-01305-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 02/06/2020] [Indexed: 12/28/2022]
Abstract
It is well known that overload changes the mechanical properties of biological tissues and fasting changes the responsiveness of intestinal afferents. This study aimed to characterize the effect of overload on mechanosensitivity in mesenteric afferent nerves in normal and fasted Sprague-Dawley rats. Food was restricted for 7 days in the Fasting group. Jejunal whole afferent nerve firing was recorded during three distensions, i.e., ramp distension to 80 cmH2O luminal pressure (D1), sustained distension to 120 cmH2O for 2 min (D2), and again to 80 cmH2O (D3). Multiunit afferent recordings were separated into low-threshold (LT) and wide-dynamic-range (WDR) single-unit activity for D1 and D3. Intestinal deformation (strain), distension load (stress), and firing frequency of mesenteric afferent nerve bundles [spike rate increase ratio (SRIR)] were compared at 20 cmH2O and 40 cmH2O and maximum pressure levels among distensions and groups. SRIR and stress changes showed the same pattern in all distensions. The SRIR and stress were larger in the Fasting group compared to the Control group (P < 0.01). SRIR was lower in D3 compared to D1 in controls (P < 0.05) and fasting rats (P < 0.01). Total single units and LT were significantly lower in Fasting group than in Controls at D3. LT was significantly higher in D3 than in D1 in Controls. Furthermore, correlation was found between SRIR with stress (R = 0.653, P < 0.001). In conclusion, overload decreased afferent mechanosensitivity in a stress-dependent way and was most pronounced in fasting rats. Fasting shifts LT to WDR and high pressure shifts WDR to LT in response to mechanical stimulation.
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Affiliation(s)
- Lingxia Bao
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing University, Chongqing, 400044, China.,Department of Clinical Medicine, Giome Academia, Aarhus University, 8200, Aarhus N, Denmark
| | - Jingbo Zhao
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing University, Chongqing, 400044, China.,Department of Clinical Medicine, Giome Academia, Aarhus University, 8200, Aarhus N, Denmark
| | - Donghua Liao
- Department of Clinical Medicine, Giome Academia, Aarhus University, 8200, Aarhus N, Denmark.,Department of Gastroenterology and Hepatology, Mech-Sense, Aalborg University Hospital and Clinical Institute, Faculty of Health Sciences, Aalborg University, Aalborg, Denmark
| | - Guixue Wang
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing University, Chongqing, 400044, China
| | - Hans Gregersen
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing University, Chongqing, 400044, China. .,Department of Surgery, GIOME, the Chinese University of Hong Kong, Pok Fu Lam, Hong Kong, SAR. .,Department of Surgery, Clinical Science Building, GIOME, Prince of Wales Hospital, Ngan Street, Shatin, Hong Kong.
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