OxyFile #253

Effects of low-dose hydrogen peroxide in the isolated perfused 
rat lung.

Author:   Habib MP; Clements NC

Source:   Exp Lung Res 1995 Jan-Feb; 21(1):95-112

Abstract:

Isolated perfused rat lungs (IPRL) were used to determine 
if treatment with hydrogen peroxide would result in measurable 
changes in exhaled ethane during the early stages of capillary 
leak. Pulmonary capillary filtration coefficient, pulmonary 
vascular resistance, and dynamic pulmonary compliance were 
measured at two time points in an IPRL. Additionally, exhaled 
ethane was determined before and after the addition of 
0.25 mM H2O2 to the perfusate in a second group of lungs. 
Lung wet/dry weight ratios were measured at the termination 
of the experiments. The ethane in the exhaled alveolar 
gas from IPRLs ventilated with 5%CO2/20%O2/balance N2 was 
quantitated using gas chromatography before and after the 
addition of 0.25 mM H2O2 to Krebs Ringer's 5% albumin perfusate. 
H2O2 (0.25 mM) caused a small but significant increase 
in capillary filtration coefficient from 0.0122 (+/- 0.0008) 
to 0.0173 (+/- 0.0013) mL/min/cm H2O/g dry lung weight 
(p < .05). Wet/dry lung weight ratios were increased in 
the H2O2-treated lungs (6.0654 +/- 0.1024 versus 5.4149 
+/- 0.1143; p < .05). Exhaled ethane did not increase over 
the period of time hydrogen peroxide was present in the 
perfusate. In other experiments in closed-chested rats, 
0.25 mM peroxide did not cause increased exhaled ethane, 
whereas 1 mM H2O2 did. This latter increase in ethane was 
not noted in similarly perfused open-chested rats. These 
data indicate that small amounts of H2O2 may increase pulmonary 
capillary permeability without affecting exhaled ethane 
measurements.