TY - JOUR
T1 - Implications of rectal preconditioning for interpretation of sensory-motor data
AU - Zhao, Jingbo
AU - Gregersen, Tine
AU - Fassov, Janne
AU - Krogh, Klaus
AU - Gregersen, Hans
N1 - Copyright © 2019 Elsevier Ltd. All rights reserved.
PY - 2020/1/23
Y1 - 2020/1/23
N2 - Testing of biomechanical properties of intestine requires the tissue to be preconditioned by applying cyclic loading to obtain repeatable mechanical data. However, little is known about the mechanosensory properties during intestinal preconditioning. We aimed to study the relationship between mechanical preconditioning of the human rectum and sensory response. Three fast rectal bag distensions to the pain threshold were done in seven healthy females. A visual analog scale (VAS) was used for sensory assessment. At each distension, we determined (1) time, bag cross-sectional area (CSA), radius (r), r/r0, pressure and tension to reach VAS = 1, 3 and 5 (pain threshold); (2) the same parameters at induced contraction start; (3) CSA where the pressure started to increase (CSAP>baseline) and (4) the number of contractions. The time, CSA, r/r0 and tension to reach VAS = 1 and VAS = 3 increased from distension 1 to 3 (4.9 < F < 11.5, 0.05 > P > 0.007), primarily due to difference between the first and second distension. For VAS = 5, r/r0 was smaller in distension 3 than distension 1 (P < 0.05), whereas time, CSA and tension did not differ between distensions (P > 0.5). Compared with distension 1, CSA, r/r0 and tension at contraction start, and CSAP>baseline were bigger in distensions 2 and 3 (5.5 < F < 10.9, 0.05 > P > 0.009). The pressure to reach the VAS levels, the contraction numbers and pressure at contraction start did not differ among distensions (P > 0.6). During mechanical preconditioning, CSA, tension and deformation increased at sub-pain levels, reflecting sensory adaptation. The data point to acute remodeling of a strain-dependent mechanism in the rectal wall.
AB - Testing of biomechanical properties of intestine requires the tissue to be preconditioned by applying cyclic loading to obtain repeatable mechanical data. However, little is known about the mechanosensory properties during intestinal preconditioning. We aimed to study the relationship between mechanical preconditioning of the human rectum and sensory response. Three fast rectal bag distensions to the pain threshold were done in seven healthy females. A visual analog scale (VAS) was used for sensory assessment. At each distension, we determined (1) time, bag cross-sectional area (CSA), radius (r), r/r0, pressure and tension to reach VAS = 1, 3 and 5 (pain threshold); (2) the same parameters at induced contraction start; (3) CSA where the pressure started to increase (CSAP>baseline) and (4) the number of contractions. The time, CSA, r/r0 and tension to reach VAS = 1 and VAS = 3 increased from distension 1 to 3 (4.9 < F < 11.5, 0.05 > P > 0.007), primarily due to difference between the first and second distension. For VAS = 5, r/r0 was smaller in distension 3 than distension 1 (P < 0.05), whereas time, CSA and tension did not differ between distensions (P > 0.5). Compared with distension 1, CSA, r/r0 and tension at contraction start, and CSAP>baseline were bigger in distensions 2 and 3 (5.5 < F < 10.9, 0.05 > P > 0.009). The pressure to reach the VAS levels, the contraction numbers and pressure at contraction start did not differ among distensions (P > 0.6). During mechanical preconditioning, CSA, tension and deformation increased at sub-pain levels, reflecting sensory adaptation. The data point to acute remodeling of a strain-dependent mechanism in the rectal wall.
KW - Load-dependent effect
KW - Mechanosensation
KW - Preconditioning
KW - Rectum
KW - Sensory-motor properties
UR - http://www.scopus.com/inward/record.url?scp=85077503717&partnerID=8YFLogxK
U2 - 10.1016/j.jbiomech.2019.109541
DO - 10.1016/j.jbiomech.2019.109541
M3 - Journal article
C2 - 31787257
SN - 0021-9290
VL - 99
JO - Journal of Biomechanics
JF - Journal of Biomechanics
M1 - 109541
ER -