Figure 2. Immunohistochemical expression of inducible nitric oxide synthase (iNOS) in the control and treatment groups of heart muscle. A, There is no immunopositive reaction of iNOS in muscle fibers of S group. B, Strongly positive iNOS immunoreactivity of heart muscle (arrowhead) in Cont group. C, Moderate immunopositive reaction in Cont+QC group. D, Intermediate iNOS immunoreactivity of heart muscle in Cont+MP group. E, Weak immunopositive reaction of iNOS in Cont+MP+QC group. S: Sham; Cont: cardiac contusion; Cont+MP: Cont group treated with methylprednisolone; Cont+QC: Cont group treated with quercetin; Cont+MP+QC: Cont group treated with methylprednisolone and quercetin. Immunoperoxidase technique, Harris hematoxylin counter staining, 3-amino-9-ethylcarbazole (AEC) as a chromogen, 20× magnification.