title: Effects of endotoxemia on systemic plasma loss and hematocrit in rats.
abstract: Endotoxemia in rats increases plasma extravasation but does not result in continuously rising hematocrit. These contradictory observations led us to design a study in anesthetized rats (C, control rats, n = 10; E, endotoxin rats, n = 10) in which we continuously measured in blood hematocrit (conductivity cell) and changes in concentration of 125I-HSA (human serum albumin) and 51Cr-labeled red cell (51Cr-RBC; multichannel analyzer) in an extracorporeal circuit. In two additional series of experiments we measured in blood samples changes in protein concentration (series II, C: n = 7, E: n = 7) and uptake of intraperitoneally injected 125I-HSA and 51Cr-RBC (reflecting lymph flow rate; series III, C: n = 6, E: n = 7). Endotoxemia was induced by infusion (iv, 0.2 ml/100 g.hr) of Escherichia coli endotoxin (20 mg/kg) from t = 0 to t = 60 min; controls received saline. Experiments ended at t = 120 (series I and II) or 150 min (series III). The endotoxemia resulted in a marked rise of serum lactate (by ca 500% at t = 120); heart rate increased and central venous pressure decreased (by ca 20 and -95% at t = 120, respectively). All rats showed characteristic changes in hematocrit during endotoxemia: an increase from t = 20 to t = 45 (by ca 9%) followed by a decrease to preshock values or less at t = 120. The 51Cr activity per microliter blood cells did not change, indicating that there was no red cell mobilization. Protein concentration and 125I-HSA activity also showed a temporary increase during endotoxemia, but 125I-HSA activity per gram protein was decreased. Peritoneal uptake of 125I-HSA and 51Cr-RBC was significantly increased during endotoxemia (by 200%). We conclude that fluid extravasation during endotoxemia is temporary, mainly concerns plasma water, and is compensated by mechanisms like reabsorption and increased lymph flow, resulting in restoration of plasma volume.
authors.affiliation: Laboratory for Physiology, Free University Amsterdam, The Netherlands.
authors.forename: A A
authors.initials: AA
authors.lastname: van Lambalgen
authors.forename: M T
authors.initials: MT
authors.lastname: Rasker
authors.forename: G C
authors.initials: GC
authors.lastname: van den Bos
authors.forename: L G
authors.initials: LG
authors.lastname: Thijs
mesh_terms: D000818:Animals; D002859:Chromium Isotopes; D002860:Chromium Radioisotopes; D004731:Endotoxins / Q000097:blood*; D004912:Erythrocytes / Q000502:physiology; D006400:Hematocrit; D006439:Hemodynamics / Q000187:drug effects; D007456:Iodine Isotopes; D010953:Plasma Volume; D051381:Rats; D011919:Rats, Inbred Strains; D012711:Serum Albumin, Radio-Iodinated
chemical_list: D002859:Chromium Isotopes; D002860:Chromium Radioisotopes; D004731:Endotoxins; D007456:Iodine Isotopes; D012711:Serum Albumin, Radio-Iodinated