Inhibition of the iNOS pathway in inflammatory macrophages by low-dose X-irradiation in vitro. Is there a time dependence?

Background: Low radiation doses (< or = 1.25 Gy), if applied 6 h before or after stimulation, are known to inhibit the inducible nitric oxide synthase (iNOS) pathway in inflammatory macrophages in vitro. We therefore investigated the time dependence and the underlying molecular mechanism of this effect, since it may be involved in the clinically observed anti-inflammatory and analgesic efficacy of low-dose radiotherapy.