Pulmonary and Extrapulmonary Effects of Increased Colloid Osmotic Pressure During Endotoxemia in Rats: Determination of Organ Water Content

After the last data collection (at 6 h), all rats were killed with IV administration of pentobarbital, following which the kidneys, lung, heart, liver, and a 15-cm section of the ileum in each rat were quickly removed. Tissues were weighed and then placed in an oven at 60°C for slow drying for > 5 days. Dry weights then were measured, and wet/dry weights were calculated for the determination of organ water content.
Statistical Analysis
All values are presented as the mean ± SD. Data at various time points within the same group were evaluated by repeated measures of analyses of variance, followed by the Dunnett multiple comparisons test. For this analysis, the values at time zero were compared with the measurements taken at 2, 4, and 6 h. Differences among the four groups at comparable time periods were evaluated with analyses of variance followed by the Tukey-Kramer multiple comparisons test. This test also was used to find the differences in the water content of the organ among all groups. Data analyses were performed only on surviving rats and/or those that completed the 6-h experimental period. my canadian pharmacy.com

Results
Group I

Experiments in this group were completed in 10 of 11 rats. The gas-exchange variables showed continued and significant increases in Pa02 level, which were accompanied by significant decreases in PaC02 level and a stable pH level (Table 1). The COP was significantly reduced within 2 to 6 h (Fig 1). In these rats, as in all other groups, an estimated 10 mL/kg blood was removed for different analyses and was replaced by saline solution. A gradual reduction in the Hb concentration from 14.4 ± 0.6 to 12.6 ± 0.8 g/dL was observed after 6 h (Fig 2), with a 10% reduction in the arterial O2 content (Fig 3). The alveolar-arterial O2 pressure difference (P[A-a]O2) was significantly reduced by 30% throughout the experiment (Fig 4). No significant changes occurred in MABP (Fig 5) and HR (Fig 6).
Fig1
Figure 1. Changes in blood COP in healthy rats (controls) and healthy rats that received albumin treatment, as well as following endotoxemia with or without albumin treatment. Endotoxin was administered IV immediately after the baseline values were determined (time zero). Boluses of 1 g/kg human albumin were administered IV immediately after time zero and at 2 and 4 h afterward. * = p < 0.05 (differences within the same group, comparing baseline values with those measured 2,4, and 6 h later using repeated measures of analysis of variance followed by Dunnett multiple comparisons test).
Fig2
Figure 2. Changes in Hb concentrations in healthy rats (controls) and healthy rats that received albumin treatment, as well as following endotoxemia with or without albumin treatment. For drug administrations and statistical comparison, see Figure 1.
Fig3
Figure 3. Changes in arterial O2 content in healthy rats (controls) and healthy rats that received albumin treatment, as well as following endotoxemia with or without albumin treatment. For drug administration and statistical comparison, see Figure 1. The O2 content at 6 h in the endotoxin-albumin-treated group is significantly lower than that in all other groups (Tukey-Kramer multiple comparisons test).
Fig4
Figure 4. Changes in P(A-a)O2 in saline solution-treated (“healthy”) rats and rats that received albumin treatment, as well as following endotoxemia with or without albumin treatment. For drug administration and statistical comparison, see Figure 1. Endotoxin-albumin-treated rats demonstrated significantly higher P(A-a)O2 values, compared to those of all other groups.
Fig5
Figure 5. Changes in MABP in healthy rats (controls) and healthy rats that received albumin treatment, as well as following endotoxemia with or without albumin treatment. For drug administration and statistical comparison, see Figure 1. Albumin treatment during endotoxemia created a consistently higher MABP than endotoxemia by itself.
Fig6
Figure 6. Changes in HR in healthy rats (controls) and healthy rats that received albumin treatment, as well as following endo-toxemia with or without albumin treatment. For drug administrations and statistical comparison, see Figure 1. Endotoxin treatment both alone and in combination with albumin treatment generated significant increases in HR, which was more pronounced in the latter group.

Table 1—Gas Exchange and Blood COP During 6 h of Maintained Anesthesia in 10 Spontaneously Breathing, Saline Solution-Treated Rats

Variables Time
IBaseline(Time Zero) 2 h 4h 6h
Pa0£, mm Hg 76.5 ± 9.2 87.5 ± 7.0i 91.4 ± 9.8i 94.0 ± 7.4i
PaC0£, mm Hg 42.4 ± 3.6 38.4 ± 3.8 36.7 ± 3.9i 32.6 ± 7.1i
ph 7.381 ± 0.03 7.352 ± 0.03 7.342 ± 0.03 7.353 ± 0.05
(HCO3)a, mmol/L 24.7 ± 2.3 20.8 ± 2.5i 19.4 ± 2.5i 17.3 ± 3.1i
HbO2, % 91.9 ± 2.3 94.7 ± 2.3 95.0 ± 1.5 96.0 ± 1.2
COP, mm Hg 14.3 ± 0.6 12.4 ± 1.6i 12.0 ± 2.0i 11.0 ± 1.7i
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