Figure 4: Immunohistochemical staining for identification of TNF-α. (a) Representative light micrograph of the complex at 15 days of ligation illustrates localization of TNF-α. (b) Representative images illustrate immunohistochemical localization of TNF-α at subepithelial connective tissue, coronal and apical PDL spaces, and interradicular PDL regions, according to experimental conditions. For example, note TNF-α expression at the distal coronal PDL-bone interface (black arrow heads). Connective tissue (CT), alveolar bone (AB), periodontal ligament (PDL), dentin (D), and secondary cementum (SC).