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Lymph pump mechanics in the rabbit hind leg
F Ikomi1, G W Schmid-Schönbein
1Department of Bioengineering, University of California, San Diego, La Jolla 92093-0412, USA.
The American Journal of Physiology
|July 1, 1996
Summary
Passive tissue movement, like leg rotation and skin massage, significantly enhances lymphatic fluid flow. This study reveals periodic expansion and compression of initial lymphatics as a key pumping mechanism, independent of capillary filtration pressures.
Area of Science:
- Physiology
- Lymphatic System Dynamics
Background:
- Mechanisms governing initial lymphatic fluid uptake and lymph flow rate regulation are not fully understood.
- Passive tissue movement's role in lymph flow has been largely unexplored.
Purpose of the Study:
- To investigate the contribution of passive tissue movement to lymphatic flow rates.
- To determine if external mechanical stimuli can modulate lymph flow independently of capillary filtration.
Main Methods:
- Lymph fluid was collected from rabbit popliteal prenodal lymphatics using cannulation.
- Lymph flow rates were measured during passive whole leg rotation and controlled oscillatory foot skin massage.
- Experiments were conducted on live rabbits and after cardiac arrest to differentiate mechanical effects.
Main Results:
- Lymph flow was minimal (< 0.01 ml/h) without passive leg rotation.
- Whole leg rotation induced a frequency-dependent, linear increase in lymph flow with the logarithm of frequency (0.03-1.0 Hz).
- Oscillatory skin massage also increased lymph flow rates, dependent on frequency and displacement amplitude, even in arrested circulation.
Conclusions:
- Periodic expansion and compression of initial lymphatics by passive tissue motion serve as an effective lymph pumping mechanism.
- Local lymph flow can be modulated by mechanical stimuli independently of capillary fluid filtration pressures.
- This study elucidates a non-capillary filtration-dependent mechanism for regulating lymph flow.