Fig. 1
From: Substance P participates in periodontitis by upregulating HIF-1α and RANKL/OPG ratio
Rat experimental periodontitis model. Healthy gingival tissue attached to teeth cervical region in Normal group (A1). Six weeks after ligation, the ligatures still firmly stayed on cervical region (B1). Obvious gingival recession of the first molars was observed at 6 weeks after ligation (B2). Compared with normal periodontal tissues (A2), gingival inflammatory infiltration and obvious alveolar bone loss were observed by hematoxylin-eosin staining (B3, B4)