J. Kjaeve et al., METHYLPREDNISOLONE ATTENUATES AIRWAY AND VASCULAR-RESPONSES INDUCED BY REACTIVE OXYGEN SPECIES IN ISOLATED, PLASMA-PERFUSED RAT LUNGS, Free radical research, 25(5), 1996, pp. 407-414
The effects of methylprednisolone (MP) on the acute airway and pulmona
ry vascular responses induced by reactive oxygen species (ROS) were in
vestigated in isolated, plasma-perfused rat lungs. ROS were generated
by adding xanthine oxidase and hypoxanthine to the perfusate. MP was a
dministered in 3 different ways: 1. Added to the perfusate (1 mgml(-1
)) 5 min prior to xanthine oxidase and hypoxanthine, 2. Given as intra
peritoneal injections (40 mgkg(-1)) to lung donor rats 12 and 2 hours
prior to the experiments, or 3. Combining 1 and 2. The lungs were per
fused at constant volume inflow (15 mlmin(-1)). Pulmonary arterial pr
essure and transpulmonary pressure were followed for 30 min after addi
tion of xanthine oxidase and hypoxanthine. ROS induced a powerful, acu
te broncho- and vasoconstriction, which was inhibited by addition of M
P to the perfusate. Pretreatment with MP also inhibited the vascular a
nd airway responses. Adding MP to the perfusate of pretreated lungs fu
rther reduced the ROS-induced smooth muscle constriction. In conclusio
n, MP inhibits vasoconstriction and bronchoconstriction induced by ROS
in isolated rat lungs.