Journal of Applied Physiology, Vol 62, Issue 2 706-710, Copyright © 1987 by American Physiological Society
Effect of endotoxin on diaphragm lymph contamination in unanesthetized sheep
R. E. Drake, S. J. Allen, J. C. Gabel, J. Katz and G. A. Laine
The preparation for collecting lung lymph from sheep caudal mediastinal
lymph node (CMN) efferent vessels is widely used to study the effects of
endotoxin on lung microvascular permeability. However, there are
nonpulmonary lymph vessels that drain into the CMN along with the afferent
lymph vessels from the lung. Thus CMN lymph is a mixture of lymph from the
lung and diaphragm lymph vessels as well as from other nonpulmonary lymph
vessels. We studied the effect of 0.5-1.0 microgram/kg Escherichia coli
endotoxin on the flow rates in diaphragm and CMN efferent lymph vessels
(Qdi and QCMN, respectively) in unanesthetized sheep. For the time period
between 2 and 5.5 h after endotoxin QCMN was increased from its base line
of 7.2 +/- 4.4 (SD) to 17.3 +/- 10.6 ml/h and the lymph-to-plasma protein
concentration ratio (L/PCMN) had increased from 0.68 +/- 0.11 to 0.81 +/-
0.06. During the same time period, Qdi was 4.5 +/- 3.1 ml/h compared with
1.0 +/- 0.8 ml/h at base line and the diaphragm lymph-to-plasma protein
concentration ratio (L/Pdi) was 0.92 +/- 0.07 (base line = 0.74 +/- 0.15).
The increases in flow rate and protein concentration were significant for
each type of vessel (P less than 0.05). We conclude that the period of
increased QCMN and L/PCMN after endotoxin is associated with an increase in
Qdi and L/Pdi. Thus, it is difficult to determine how much of the CMN lymph
response comes from the lungs and how much comes from diaphragm lymph
vessels.
