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Tissue contribution to the mechanical features of diaphragmatic initial lymphatics
Author(s) -
Moriondo Andrea,
Boschetti Federica,
Bianchin Francesca,
Lattanzio Simone,
Marcozzi Cristiana,
Negrini Daniela
Publication year - 2010
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2010.196204
Subject(s) - lymphatic system , anatomy , lumen (anatomy) , diaphragmatic breathing , lymph , lymphatic vessel , chemistry , materials science , biomedical engineering , medicine , pathology , surgery , alternative medicine , cancer , metastasis
The role of the mechanical properties of the initial lymphatic wall and of the surrounding tissue in supporting lymph formation and/or progression was studied in six anaesthetized, neuromuscularly blocked and mechanically ventilated rats. After mid‐sternal thoracotomy, submesothelial initial lymphatics were identified on the pleural diaphragmatic surface through stereomicroscopy. An ‘ in vivo ’ lymphatic segment was prepared by securing two surgical threads around the vessel at a distance of ∼2.5 mm leaving the vessel in place. Two glass micropipettes were inserted into the lumen, one for intraluminar injections of 4.6 nl saline boluses and one for hydraulic pressure ( P lymph ) recording. The compliance of the vessel wall ( C lymph ) was calculated as the slope of the plot describing the change in segment volume as a function of the post‐injection P lymph changes. Two superficial lymphatic vessel populations with a significantly different C lymph (6.7 ± 1.6 and 1.5 ± 0.4 nl mmHg −1 (mean ± s.e.m. ), P < 0.001) were identified. In seven additional rats, the average elastic modulus of diaphragmatic tissue strips was determined by uniaxial tension tests to be 1.7 ± 0.3 MPa. C lymph calculated for an initial lymphatic completely surrounded by isotropic tissue was 0.068 nl mmHg −1 , i.e. two orders of magnitude lower than in submesothelial lymphatics. Modelling of stress distribution in the lymphatic wall suggests that compliant vessels may act as reservoirs accommodating large absorbed fluid volumes, while lymphatics with stiffer walls serve to propel fluid through the lumen of the lymphatic vessel by taking advantage of the more efficient mechanical transmission of tissue stresses to the lymphatic lumen.