Nitric oxide increases the survival of rats with a high oxygen exposure.
The purpose of this study was to begin to examine the influence of inhaled NO on O2 toxicity. The survival of Sprague-Dawley rats exposed to >95% O2, >95% O2 + 10 ppm NO, >95% O2 + 100 ppm NO, and >95% O2 + 3 ppm NO2 was determined. Survival at 120 h was 2/24 in >95% O2, 2/12 in >95% O2 + 10 ppm NO, and 1/12 in >95% O2 + 3 ppm NO2. Survival at 120 h was 21/30 in >95% O2 + 100 ppm NO (p < 0.01 compared with >95% O2). Three additional groups of rats were exposed for 60 h to: 21% O2, >95% O2, or >95% O2 + 100 ppm NO. The lungs were then assayed for total protein, reduced (GSH) and oxidized glutathione (GSSG), and 4-hydroxy-2(E)-nonenal. Both of the high O2 groups had significantly (p < 0.05) lower GSH/mg protein and GSH/GSSG ratios compared with the 21% O2 group. The >95% O2 group had a higher 4-hydroxy-2(E)-nonenal/mg of protein than either the 21% O2 group (p < 0.05), or the >95% O2 + 100 ppm NO group (p < 0.05 compared with >95% O2, not different from the 21% O2 group). Additional groups of rats were exposed to either 21% O2, >95% O2, or >95% O2 + 100 ppm NO for 0, 24, 48, and 60 h. The lungs were examined for neutrophil accumulation, which was increased at 60 h in the two groups exposed to >95% O2, but adding NO had no effect. Thus, the overall result was that 100 ppm inhaled NO improved the survival of rats in high O2.
Nelin
L D
LD
Department of Pediatrics, Medical College of Wisconsin, Milwaukee 53226, USA.
Welty
S E
SE
Morrisey
J F
JF
Gotuaco
C
C
Dawson
C A
CA
D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D018496:Hyperoxia / Q000503:physiopathology* / Q000628:therapy; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000627:therapeutic use*; D010100:Oxygen / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015996:Survival Rate; D013997:Time Factors
D000447:Aldehydes; D015853:Cysteine Proteinase Inhibitors; D009569:Nitric Oxide; D005978:Glutathione; C027576:4-hydroxy-2-nonenal; D010100:Oxygen; D019803:Glutathione Disulfide