In vivo determination of diffusive transport parameters in a superfused tissue
| Autor: | Ravi Deverkadra, Jeremy Smitherman, Michael F. Flessner, Xiarong Li, Kimberly Credit |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Nitroprusside
Physiology Diffusion Vasodilator Agents Analytical chemistry Vascular permeability Thermal diffusivity Models Biological Capillary Permeability Rats Sprague-Dawley Norepinephrine Peritoneum In vivo Mass transfer medicine Animals Vasoconstrictor Agents Mannitol Carbon Radioisotopes Mass transfer coefficient Chemistry Water Biological Transport Diuretics Osmotic Rats Solutions medicine.anatomical_structure Female medicine.drug |
| Zdroj: | American journal of physiology. Renal physiology. 291(5) |
| ISSN: | 1931-857X |
| Popis: | To address the hypothesis that functional changes in tissue transport can be related to structural alterations, we combined mathematical modeling with in vivo experimentation. The model concept includes interstitial diffusion and removal by a distributed microvasculature. Transport of solute and water across the peritoneum is measured via a plastic chamber affixed to the abdominal wall of anesthetized Sprague-Dawley rats. Solutions containing [14C]mannitol, with or without vasoactive compounds [control (C; n = 10), C + nitroprusside (NP; n = 10), C + norepinephrine (NE; n = 10)], were infused into the chamber, and the volume and tracer concentrations were determined over 60 min to calculate the mass transfer coefficient (MTC) and the water flux. At 60 min, FITC-dextran (500 kDa) was given to mark the perfused vasculature. After euthanasia, the tissue under the chamber was frozen, dried, sliced with a cryomicrotome, and examined with fluorescent microscopy and quantitative autoradiography. The microvessel density (×103/cm2: NE, 50 ± 10; C, 180 ± 7.0; NP, 225 ± 15) resulted in marked differences ( P < 0.05) in water flux (μl·min−1·cm−2: NE, 0.1 ± 0.1; C, 1.6 ± 0.4; NP, 1.0 ± 0.2) and in mannitol MTC (×103cm/min: NE, 0.9 ± 0.3; C, 3.8 ± 0.3; NP, 3.6 ± 0.6). Concentration profiles and calculated capillary permeability and tissue diffusivity were significantly different among the groups. These results demonstrate a direct correlation of mass transfer, diffusion, capillary permeability, and water flux with peritoneal vascular density and validate a method by which mechanistic changes in transport may be measured. |
| Databáze: | OpenAIRE |
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