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Updated: Oct 21, 2026
The Mouse Isolated Perfused Kidney Technique
Published on: November 17, 2016
Effects of blood-free and protein-free perfusion on CFC in the isolated cat hindlimb
Insights
Blood and protein significantly impact capillary filtration coefficient (CFC). Albumin and a blood-albumin mixture increased CFC, suggesting two distinct pathways for water flow across capillaries.
Area of Science:
- Physiology
- Biophysics
Background:
- Capillary filtration coefficient (CFC) is a key indicator of microvascular permeability.
- Understanding factors influencing CFC is crucial for diagnosing and treating edema and other fluid balance disorders.
Purpose of the Study:
- To investigate the effects of blood and protein on capillary filtration coefficient (CFC).
- To elucidate the role of perfusate composition in regulating transcapillary water movement.
Main Methods:
- Isolated cat hindlimbs were perfused with three different solutions: dialysate, dialyzed bovine serum albumin (BSA), and a control solution (albumin plus cat blood).
- Constant flow perfusion was maintained, and CFC was measured over time for each perfusate.
Main Results:
- Perfusion with dialysate and albumin significantly increased CFC compared to the control.
- The magnitude of CFC increase was dependent on the baseline control CFC, indicating a complex interaction.
- The results suggest the presence of at least two distinct transcapillary water pathways.
Conclusions:
- One transcapillary pathway appears to have a constant hydraulic capacity, unaffected by blood or protein.
- A second pathway's hydraulic capacity varies and requires blood and protein for normal function.
- These findings provide insights into the mechanisms governing capillary fluid exchange.
Abstract:
To investigate the effects of blood and protein on capillary filtration coefficient (CFC), isolated cat hindlimbs were perfused at constant flow from a reservoir containing one of three perfusates: 1) an electrolyte solution also used for dialyzing bovine serum albumin (BSA) and hence labeled dialysate, 2) dialyzed 6.5-7.0 g/100 ml BSA, labeled albumin, and 3) albumin plus cat blood, labeled control. CFC during control perfusion averaged 0.0137 +/- 0.003 (SD, n = 26) and increased slowly with time. CFCs with dialysate and albumin were 3.1 +/- 0.56 (n = 11) and 1.7 +/- 0.52 (n = 15) times control, respectively. However, the ratio in a particular experiment depended on control CFC, the ratio being low when the control CFC was low and high when control CFC was high. The data can be explained if water flow occurs through two types of transcapillary pathways, one having a hydraulic capacity constant from animal to animal and insensitive to blood and protein, the second varying in hydraulic capacity and requiring blood and protein for its normal values.
