Using a coronary ligation-induced myocardial infarction (MI) rat model, we observed a marked increase in Iba1-positive macrophages and the pro-inflammatory macrophage marker Interferon regulatory factor 8 (IRF8) in thoracic (T1-T4) dorsal root ganglia (DRGs) starting at four weeks post-MI and persisting for at least four weeks. The gene discussed is IRF8; the disease is myocardial infarction.