Irradiation modulates M1 and M2 macrophage accumulation in TA muscle. Hind limb was submitted to 20 Gy 24 h before injury to inhibit proliferation of resident cells. Rats were treated, or not, with daily intravenous injection of liposome-encapsulated clodronate starting 24 h prior to injury until euthanasia at 4 d post-injury, for analysis of the numbers of M1 and M2 macrophages into injured muscle. (A) Irradiation significantly decreased M1 macrophage accumulation when monocytes were depleted. (B) Irradiation impaired the accumulation of M2 macrophages following depletion or not. *Significantly different from the non-irradiated condition homologous, Student’s t-test, p < 0.05. n = at least 3, for all the time points and conditions evaluated.