Objective: The aim of the study was to determine the expression of cell proliferating marker, anti-proliferating cell nuclear antigen (anti-PCNA) and mesenchymal stem cell (MSC) markers (anti-STRO-1 and anti-CD44) in periapical periodontitis and their role in the healing of periapical lesion in periapical periodontitis.
Materials and methods: Ninety Sprague-Dawley male rats (100 g) were divided into 3 groups: Experimental group I (EG I: n = 30), experimental group II (EG II: n=30) and control group (CG: n = 30). Periapical lesions were experimentally developed by leaving the dental pulp of maxillary first molars mesial root open to oral environment for 4 weeks. Conventional root canal treatment was performed in EG II. Maxillary first molars along with alveolar bone were resected and fixed. The processed samples were stained with routine hematoxylin and eosin (H&E), and evaluated immunohistochemically using antibodies against anti-PCNA, anti-STRO-1, and anti-CD44 polyclonal antibodies. Data were analyzed using Chi-square test and a p-value of <0.05 was considered significant.
Results: Immunostaining of anti-PCNA showed 30%, 70% and 53.3% positive staining in CG, EG I, and EG II, respectively (p<0.001). Moreover, the CD44 staining was 20% in CG in contrast to 63.6% in EG I and 43.3 in EG II. STRO-1 staining in CG was 10%, 50% in the EG I and 36.6% in the EG II (p<0.001).
Conclusions: Periapical inflammatory tissues expressed significant proliferative cell marker PCNA and mesenchymal stem cell markers STRO-1, and CD44. These findings further reaffirm the promising role of mesenchymal stem cells in the healing of periapical periodontitis.