PMN sequestration in PMA injured lung

Polymorphonuclear neutrophils (PMN) mediate lung injury to phorbol myristate acetate (PMA). We hypothesized that PMA would increase pulmonary PMN sequestration (Seq.) PMN were isolated from the blood of the lung donor and radiolabeled with 'Chromium ("Cr). Isolated canine lung lobes were ventilated and pump perfused with blood. "CrPMN and indocyanine green dye were injected via the arterial catheter and venous samples were collected over 12 sec at 0.6 sec intervals for first pass uptake and lung blood volume determination. PMA (0.1 ug/ml blood, n=3) or vehicle, dimethyl sulfoxide, (DMSO, n=4) was then added to the venous reservoir. At 30 min inflow and outflow to the lung were clamped and the tissue containing blood was homogenized. Homogenate and circulating blood (Bid.) ⁵¹Cr content were assayed. MEASURE PMA DMSO Seq. 51Cr-PMN/[Bld. 51Cr-PMN]/g 26.43±7.64 6.46±1.03 Seq. 51Cr-PMN/[Bld. 51Cr-PMN] 420.2±115.3 145.0±24.1 Total 51Cr-PMN/[Bld 51Cr-PMN] 460.91103.1 217.9±24.2 PMA tended to increase pulmonary ⁵¹Cr-PMN sequestration.