The Effect of Steroidal and Nonsteroidal Anti-inflammatory Agents on Granulocyte Migration into Bovine Pulmonary Artery Intimal Explants

Abstract

To determine whether steroidal or nonsteroidal anti-inflammatory agents inhibit granulocyte migration, we measured granulocyte adherence to and migration across the intact endothelial layer of bovine pulmonary artery intimal explants. Explants were placed endothelium uppermost in chemotaxis chamber with either fetal calf serum (FCS) or zymosan activated plasma (ZAP) in medium 199 in the lower well and 5 × 10⁶ separated ⁵¹Cr labelled granulocytes/ml in medium 199 + FCS in the upper well. Methylprednisolone (0.3 and 3.0 mg/ml), indomethacin (5 and 50 μM) and ibuprofen (10 and 100 μM) were also added to the upper well of some chambers. After 30, 60, 120 or 180 minutes of incubation the chambers were dismantled. Granulocyte adherence was assessed by rinsing the explant in 0.1% trypsin; the number of radioactive counts in the trypsin wash represented the number of adherent cells. Those remaining in the explant represented the number of granulocytes that migrated into the explant. At each time studied, chemotaxin-induced granulocyte migration was 2–3 times that of unstimulated or random migration (180 min incubation with FCS=30.5% ± S.E. 2.1; with ZAP in lower well = 61.6 ± 3.4). Both unstimulated and chemotaxin-induced migration was significantly decreased from 30 minutes by 3.0 mg/ml of methylprednisolone (180 min incubation with ZAP in lower well = 22.3 ± 5.8), but not by 0.3 mg/ml. However, one hour pretreatment of either the granulocytes or the explant with 3.0 mg/ml methylprednisolone had no significant effect on granulocyte migration. In contrast, granulocyte migration was unaltered by treatment with either indomethacin or ibuprofen. Methylprednisolone, indomethacin and ibuprofen had little effect on granulocyte adherence. We conclude that granulocyte migration across an intact endothelial layer is inhibited by high dose corticosteroids but not by cyclooxygenase inhibitors. This suggests a plausible rationale for use of high doses of corticosteroids in clinical states where granulocytes may mediate tissue injury.