In vivo analysis of the presence of heme oxygenase‐1, transcription factor Jun‐D and CD90+/CD73+/CD105+/CD45‐ cells in the pulp of bleached teeth

• Published in: International endodontic journal Vol. 52; no. 12; pp. 1723 - 1737
• Main Authors: Benetti, F., Briso, A. L. F., de Araújo Lopes, J. M., Carminatti, M., Conti, L. C., Gallinari, M. O., Ervolino, E., Cintra, L. T. A.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01-12-2019
• Subjects: Animals; Bleaching; CD105 antigen; CD45 antigen; CD73 antigen; CD90 antigen; dental bleaching; Dental Pulp; Dentistry; Endodontics; Heme; Heme Oxygenase-1; Hydrogen peroxide; Immunofluorescence; Inflammation; Jun‐D; Mesenchyme; Molars; Oxidative stress; Oxygenase; Rats; Rats, Wistar; Stem cell transplantation; Stem cells; Teeth; Tooth Bleaching; Tooth Bleaching Agents; dental bleaching; stem cells; dental pulp; Jun-D; heme oxygenase-1; hydrogen peroxide
• ISSN: 0143-2885; 1365-2591
• DOI: 10.1111/iej.13190

Aim
To investigate hydrogen peroxide (H2O2)‐induced responsiveness in pulp cells using heme oxygenase‐1 (HO‐1) immunolabelling, Jun‐D immunolabelling to study the effects of H2O2 on odontoblastic differentiation and CD90+/CD73+/CD105+/CD45‐ cell counting for in vivo identification of mesenchymal stem cells in the pulp.
Methodology
The maxillary molars of 50 rats were treated with a bleaching gel (35% H2O2, 1 × 30 min) or placebo gel (control groups). At 2, 3, 7, 15 and 30 days after the treatment (n = 10), inflammation in pulp tissue was analysed by haematoxylin–eosin staining, HO‐1‐ and Jun‐D‐immunolabelled cells were counted in each third of the pulp chamber, and the number of CD90+/CD73+/CD105+/CD45‐ cells was quantified by immunofluorescence. The results were assessed using the Paired t‐test or Wilcoxon signed‐rank test (P < 0.05).
Results
Significant H2O2‐induced inflammation was noted at 2 and 3 days (P < 0.05), with tertiary dentine formation occurring from 7 days. The bleached specimens had greater HO‐1 immunolabelling in the middle and cervical thirds of the coronal pulp at 2 and 3 days, in all thirds at 7 days, and in the occlusal third at 15 days (P < 0.05), and significant nuclear Jun‐D immunolabelling in the cervical third at 2 and 3 days and in the occlusal and middle thirds at 7 days (P < 0.05). Bleached and control groups had low numbers of CD90+/CD73+/CD105+/CD45‐ cells in the pulp at all periods (P > 0.05).
Conclusions
Pulp cells responded to oxidative stress by expressing HO‐1 during the post‐bleaching inflammation phase until the beginning of the repair phase. Jun‐D expression occurred during the reduction of inflammation and the beginning of tertiary dentine production. The presence of oxidative stress did not influence the number of CD90+/CD73+/CD105+/CD45‐ cells identified in vivo in the dental pulp.