Prevention of alpha-naphthylthiourea-induced pulmonary edema with fructose-1,6-diphosphate

Neutrophil-derived oxygen free radicals have been implicated in the pathogenesis of noncardiogenic pulmonary edema. Fructose-1,6-diphosphate (FDP) has been shown to inhibit oxygen free radicals production by activated neutrophils. Thus, we investigated whether FDP would attenuate formation of pulmonary edema in anesthetized dogs injected with alpha-naphthylthiourea (ANTU). Hemodynamic studies involved measurements of left ventricular systolic and end-diasystolic pressures (LVSP and LVEDP), pulmonary artery pressure (PaP), heart rate (HR), and cardiac output (CO). Mean wet weight to dry weight ratios of lung tissue samples were calculated. Following baseline measurements, dogs were injected intravenously (IV) with ANTU 5 mg / kg (n = 16) and 10 mg / kg (n = 8) and half of the dogs were randomly selected to receive 75 mg / kg FDP (10%) and subsequent infusion of 7 mg / kg / min. The rest were given 0.9% NaCl in the same manner. Four hours after ANTU administration, the animals were euthanatized. Except for decline in the CO (nonsignificant), no significant changes in systemic hemodynamics within and between the groups were noted. In the FDP group, PaP and pulmonary arteriolar resistance (PaR) remained unchanged. In the saline group, PaP increased from 12.5 +/- 2.44 to 21.8 +/- 3.14 mm Hg (P < .001) and PaR from 166 +/- 29 to 468 +/- 74 dynes. cm / sec(5) (P < .005). During the study LVDEP, PaO(2), PaCO(2), and hematocrit did not change significantly within and between the groups. The lungs mean wet weight to dry weight ratios for the sham-operated dogs were 4.20 +/- 0.41, for the FDP group 4.32 +/- 0.59 and 6.22 +/- 1.37 for the saline group (P < .0005). These data indicate that FDP protected the lung from ANTU-induced injury.