[The effect of posttreatment with isoflurane versus propofol on pulmonary alveolar capillary barrier in endotoxemic rats].
OBJECTIVE
To compare the effects of posttreatment with isoflurane versus propofol on pulmonary alveolar capillary barrier (PACB) in endotoxemic rats.


METHODS
Ninety-six male Sprague-Dawley rats weighing 250 to 350 g were randomly divided into 6 equal groups to be administered with intravenous lipopolysaccharide (LPS, 4 mg/kg) or equivalent volume of normal saline (NS) and treated with intravenous pentobarbital (C, 20 mg x kg(-1) x h(-1)), inhaled isoflurane (I, 0.55%) or intravenous propofol (P, 10 mg/kg bolus, 40 mg x kg(-1) x h(-1)) 2 hours after the establishment of endotoxemic model: NS-C, NS-I, NS-P, LPS-C, LPS-I, and LPS-P groups. The rats were ventilated for 2 h. The mean arterial pressure (MAP) and arterial blood gas were assessed hourly for 4 h. One cohort (n = 8 per group) was subjected to bronchial alveolar lavage in the left lungs for determination of protein concentration in the bronchial alveolar lavage fluid (BALF) and the lung permeability index (LPI, BALF protein concentration/serum protein concentration). Then the right lungs were removed to undergo light and electron microscopy and measurement of the wet wet-to-dry weight ratio (WW/WD). In a second cohort (n = 8 per group), Evans blue dye (EBD, 30 mg/kg) was injected 30 min before the end of the experiment to determine the EBD content in the lung.


RESULTS
The MAP, pH, PaCO(2), and PaO(2) were not different significantly within the three NS groups and the three LPS groups and WW/WD did not show any difference among all six groups. The LPI and EBD content in lung were significantly higher in the LPS-C group [8.1 x 10(-3) +/- 2.4 x 10(-3) and 0.628 +/- 0.082 absorption unit (AU) respectively] than in NS-C group (3.3 x 10(-3) +/- 2.2 x 10(-3) and 0.479 +/- 0.154 AU respectively, both P < 0.05), and were higher in the LPS-P group (9.1 x 10(-3) +/- 2.2 x 10(-3) and 0.664 +/- 0.028 AU respectively) than in the LPS-I group (5.5 x 10(-3) +/- 2.0 x 10(-3) and 0.517 +/- 0.048 AU respectively, both P < 0.05). Light microscopy showed more severe lung injury changes in the LPS groups than in the NS groups, especially in the LPS-P group. Electron microscopy found that the tight junctions between the adjacent pulmonary microvascular endothelial cells in the LPS-P groups were disrupted.


CONCLUSIONS
Compared with posttreatment with propofol, posttreatment with isoflurane protects the PACB function and decreases the pulmonary permeability in endotoxemic rats.
Zhang
Hong
H
Department of Anesthesiology and Critical Care Medicine, Fudan University Affiliated Zhongshan Hospital, Shanghai 200032, China.
Xue
Zhang-Gang
ZG
Jiang
Hao
H
D000818:Animals; D015824:Blood-Air Barrier / Q000187:drug effects*; D002196:Capillaries; D002199:Capillary Permeability / Q000187:drug effects*; D019446:Endotoxemia / Q000503:physiopathology*; D007530:Isoflurane / Q000493:pharmacokinetics / Q000494:pharmacology*; D008070:Lipopolysaccharides; D008168:Lung / Q000098:blood supply; D008297:Male; D015742:Propofol / Q000493:pharmacokinetics / Q000494:pharmacology*; D011650:Pulmonary Alveoli / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D008070:Lipopolysaccharides; D007530:Isoflurane; D015742:Propofol