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The effects of low dose lipopolysaccharide on the microcirculation of conscious rats in vivo
Author(s) -
McGown Caroline C,
Ross Jonathan J,
Reilly Charles S,
Brown Nicola J,
Brookes Zoe L
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1151-d
Subject(s) - microcirculation , constriction , intravital microscopy , saline , in vivo , lipopolysaccharide , dorsum , sepsis , medicine , hemodynamics , chemistry , anesthesia , endocrinology , anatomy , biology , microbiology and biotechnology
This study utilised the dorsal microcirculatory chamber (DMC) model to determine the time‐dependent effects (0–24 hours; hrs) of sepsis on the skeletal muscle microcirculation of conscious rats. 3 weeks following implantation of the dorsal microcirculatory chamber in male Wistar rats (220–260g) sepsis was induced and maintained using a low‐dose continuous infusion of lipopolysaccharide (LPS, 150μg/kg/hr) (n=6) or equivalent volume of saline (8.0 μl/hr) (n=4) in to the jugular vein. 0.25ml/100g FITC‐BSA (iv) was administered into the tail vein and intravital microscopy used to determine the diameters of arterioles and venules at 0, 1, 2, 4, 8 and 24 hrs. Results are shown as mean ±SEM. With LPS there was constriction of arterioles (A1: 83.7 +6.7μM; 0 hrs, 74.5 +8.8μM; 1 hr, A3: 30.6 +4.0μM; 0hrs, 20.7 +4.0μM; 1 hr) (P<0.05) and dilation of venules (V1: 201.7 +24.1μM; 0 hrs, 216.6 +21.7μM; 1 hr, V3: 52.7 +9.3μM; 0hrs, 69.2 +16.1μM; 1 hr) between 0–2hrs. At 4 hrs there was dilation of arterioles (A1: 92.0 +6.6μM, A3: 38.2 ±5.3μM) (P<0.05) and venules (V3: 73.6 ±10.2 μM) (P<0.05) and these responses were maintained at 24 hrs. This study is the first to determine time dependent changes in the microcirculation over 24 hrs in conscious rats with a non lethal dose of LPS. In our model vasodilation, which is characteristic of sepsis, did not appear until 4 hrs after LPS administration.