Expression of pulmonary mRNA encoding ICAM-1, VCAM-1, and P-selectin following thoracic irradiation in mice.

PURPOSE: Recent studies have revealed that ionizing radiation induces the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and P-selectin in vitro. The purpose of this study was to investigate the expression of these adhesion molecules in mouse lung following whole thoracic irradiation. MATERIALS AND METHODS: C57BL/6J mice were irradiated with a single dose of 12 Gy to the thoraces and sacrificed at 4, 12, 24, and 48 hours and 1, 2, 4, and 8 weeks after irradiation. Expression of total lung mRNA for ICAM-1, VCAM-1, and P-selectin was quantified by the Northern blot method and normalized to beta-actin. RESULTS: There were increases in mRNA for ICAM-1 of 42% at 4 hours (p < 0.05), 76% at 24 hours (p < 0.01), and 51% at 48 hours (p < 0.05) compared with the controls. These returned to the control level at 1 week. The expression of VCAM-1 mRNA was also increased by 49% (p < 0.01) at 12 hours and was still increased by 25% at 1 week. P-selectin mRNA was transiently increased by 59% at 12 hours. CONCLUSIONS: These early inductions of mRNA for ICAM-1, VCAM-1, and P-selectin in mouse lung following thoracic irradiation were transient but significant, and are one of the most immediate changes reported in vivo.