Mechanical properties of the tracheal mucosal membrane  in the rabbit. I. Steady-state stiffness as a function of age

Wang, Lu; Tepper, Robert S.; Bert, Joel L.; Pinder, K. L.; Paré, Peter D.; Okazawa, Mitsushi

doi:10.1152/jappl.2000.88.3.1014

Cited by 36 publications

(34 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the airway wall is a thick, multilayered structure, the stress in the airway wall may vary from the ideal case. Also, our protocol measured static mechanical properties of the mucosa, and stress may vary under the dynamic conditions present in breathing (11). At 5 cmH 2 O the stress was calculated to be 7.6 Ϯ 0.6 g/cm 2 , and at 25 cmH 2 O it was 72.9 Ϯ 4.0 g/cm 2 .…”

Section: Discussionmentioning

confidence: 99%

Elastic properties of the bronchial mucosa: epithelial unfolding and stretch in response to airway inflation

Noble¹,

Sharma²,

McFawn³

et al. 2005

Journal of Applied Physiology

View full text Add to dashboard Cite

The bronchial mucosa contributes to elastic properties of the airway wall and may influence the degree of airway expansion during lung inflation. In the deflated lung, folds in the epithelium and associated basement membrane progressively unfold on inflation. Whether the epithelium and basement membrane also distend on lung inflation at physiological pressures is uncertain. We assessed mucosal distensibility from strain-stress curves in mucosal strips and related this to epithelial length and folding. Mucosal strips were prepared from pig bronchi and cycled stepwise from a strain of 0 (their in situ length at 0 transmural pressure) to a strain of 0.5 (50% increase in length). Mucosal stress and epithelial length in situ were calculated from morphometric data in bronchial segments fixed at 5 and 25 cmH2O luminal pressure. Mucosal strips showed nonlinear strain-stress properties, but regions at high and low stress were close to linear. Stresses calculated in bronchial segments at 5 and 25 cmH2O fell in the low-stress region of the strain-stress curve. The epithelium of mucosal strips was deeply folded at low strains (0 -0.15), which in bronchial segments equated to Յ10 cmH2O transmural pressure. Morphometric measurements in mucosal strips at greater strains (0.3-0.4) indicated that epithelial length increased by ϳ10%. Measurements in bronchial segments indicated that epithelial length increased ϳ25% between 5 and 25 cmH2O. Our findings suggest that, at airway pressures Ͻ10 cmH2O, airway expansion is due primarily to epithelial unfolding but at higher pressures the epithelium also distends. mucosal folds; epithelium; airway mechanics THE AIRWAY MUCOSA HAS SEVERAL important roles in airway and lung biology. The mucosa contributes to mechanical properties of the airway wall that may influence the degree of airway expansion produced by lung inflation and the extent to which the airway narrows in response to bronchoconstrictor substances. The mucosa comprises the epithelium (with its basement membrane), lamina propria glands, vascular tissue, and an elastic matrix. The epithelium is a continuous layer of cells, with numerous folds that deepen on lung deflation or airway smooth muscle (ASM) contraction (9, 12). By its position internal to ASM, the mucosa imposes an afterload on ASM that may be substantial enough to restrict ASM shortening and, thus, active airway narrowing in response to bronchoconstrictor substances (5, 12). Elastic properties of the mucosa also contribute to the pressure-volume behavior of the airway wall. On lung inflation, the airway lumen expands and the depth of epithelial folds is progressively reduced, which help accommodate the increased volume of the airway lumen (4, 5, 10).Structural and mechanical properties of the mucosa potentially affect the response of the airway wall to lung inflation, deflation, and ASM contraction.Folding properties of the epithelium relevant to ASM contraction have been widely studied (4 -6, 10, 12). The mechanisms of mucosal expansion during lung inflation are less ...

show abstract

Section: Discussionmentioning

confidence: 99%

Elastic properties of the bronchial mucosa: epithelial unfolding and stretch in response to airway inflation

Noble¹,

Sharma²,

McFawn³

et al. 2005

Journal of Applied Physiology

View full text Add to dashboard Cite

show abstract

“…Nonetheless, TR translates in vivo into a reduction of ASM shortening and bronchospasm so that viscoelastic properties need to be investigated during development to evaluate the relevance of our results to an in vivo response. A recent study in rabbit has investigated steady-state stiffness of tracheal mu-cosal membrane as a function of age (28) but has failed to show significant changes with age. A similar study would be important in our model to address the specific issue of relaxation as well as possible differences among species.…”

Section: Discussionmentioning

confidence: 99%

Relaxation of guinea pig trachealis during electrical field stimulation increases with age

Chitano

Cox

Murphy

2002

Journal of Applied Physiology

View full text Add to dashboard Cite

Our laboratory has previously shown that maturation of airway smooth muscle (ASM) contractility may play a role in the airway hyperresponsiveness displayed by juveniles of many species, including humans (Chitano P, Wang J, Cox CM, Stephens NL, and Murphy TM. J Appl Physiol 88: 1338-1345, 2000). ASM relaxation, which could also contribute to airway hyperresponsiveness, has neither been described nor quantified during maturation. Therefore, we studied ASM relaxation during and after electrical field stimulation (EFS) in tracheal strips from 1-wk-old, 3-wk-old, and 3-mo-old guinea pigs. Strips were stimulated (60 Hz, 18 V) at their optimal length for 15, 20, and 25 s, with and without the cyclooxygenase inhibitor indomethacin. To evaluate the role of the epithelium, deepithelialized strips from adult animals were also studied. New indexes were developed to quantify relaxation during EFS. We measured the time course of tension relaxation and its maximum rate (RTR) during the EFS, as well as the residual tension at the end of the EFS (TCT(end)). After EFS, we measured the maximum RTR and the time needed to reduce to half the TCT(end). Relaxation during the EFS significantly increased with age. Indomethacin reduced this age difference by increasing relaxation in strips from younger animals. By contrast, removal of the epithelium in adult strips decreased relaxation. Relaxation after EFS decreased with age and was not affected by indomethacin. In adult strips, it was further reduced by epithelium removal. Our results show that during EFS 1) airway smooth muscle relaxation increases with age, 2) cyclooxygenase metabolites oppose relaxation in younger animals, and 3) epithelium removal inhibits relaxation. We suggest that a reduced ASM relaxing ability during stimulation may be involved in juvenile airway hyperresponsiveness.

show abstract

“…For this purpose, we analyzed the biomechanical behavior of the isolated trachea of dolphins when subjected to classical mechanical structural tests (Fung, 1993), as described in the literature by other authors who performed tests on tracheal cartilage (Lambert et al, 1991;Rains et al, 1992) or smooth muscle (Wang et al, 2000) of human beings (Ogawa, 1959;Meyers et al, 1980;Begis et al, 1988) or terrestrial animals (Penn et al, 1989;Codd et al, 1994). To check for possible differences, we also tested tracheae of terrestrial mammals such as the pig and the goat and compared the data with the ones obtained by testing dolphin tracheal samples.…”

mentioning

confidence: 99%

Structure and biomechanical properties of the trachea of the striped dolphin Stenella coeruleoalba: Evidence for evolutionary adaptations to diving

et al. 2005

View full text Add to dashboard Cite

This study analyzes the structure and mechanical properties of the trachea of the striped dolphin Stenella coeruleoalba, one of the most common cetacean species. The cetacean trachea is made up of closed or semiclosed cartilaginous rings without a paries membranaceus. Our results indicate that the inner lining of the trachea contains erectile tissue in which several venous lacunae permeate the mucosa. We also observed and described the presence of peripheral neurons containing nitric oxide along the rim of the venous lacunae. Data obtained from compression and tensile tests and comparison with the pig and goat tracheas indicate a higher stiffness and a different, higher breaking point for the dolphin trachea. On the whole, our data suggest that the trachea of the striped dolphin possesses structural properties that allow rapid filling with blood, possibly in relation to dive activities, and also allow modifications due to increased pressure and immediate return to the original shape without risks of permanent bending or rupture, as would happen in a terrestrial mammal. As the organ undergoes intense pressure difference during descent to optimal foraging depth and subsequent rapid ascent to surface, especially in deep dives of hundreds of meters, the specific structural and biomechanical peculiarities of the trachea of the striped dolphin may represent an evolutionary adaptation to life in the water and to diving.

show abstract

Mechanical properties of the tracheal mucosal membrane in the rabbit. I. Steady-state stiffness as a function of age

Cited by 36 publications

References 21 publications

Elastic properties of the bronchial mucosa: epithelial unfolding and stretch in response to airway inflation

Elastic properties of the bronchial mucosa: epithelial unfolding and stretch in response to airway inflation

Relaxation of guinea pig trachealis during electrical field stimulation increases with age

Structure and biomechanical properties of the trachea of the striped dolphin Stenella coeruleoalba: Evidence for evolutionary adaptations to diving

Contact Info

Product

Resources

About