In vivo and in vitro radiotherapy increased dentin enzymatic activity

• Published in: Journal of dentistry Vol. 100; p. 103429
• Main Authors: Cunha, Sandra Ribeiro, Maravic, Tatjana, Comba, Allegra, Ramos, Pedro Augusto, Tay, Franklin R., Pashley, David H., Fregnani, Eduardo Rodrigues, Aranha, Ana Cecília, Mazzoni, Annalisa, Breschi, Lorenzo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2020; Elsevier Limited
• Subjects: Densitometers; Dental Bonding; Dentin; Dentin-Bonding Agents; Dentistry; Enamel; Endogenous enzymatic activity; Enzymatic activity; Fluorescein; Fluorescence; Gelatin; Gelatinase B; Head & neck cancer; Head and neck cancer; Humans; Kruskal-Wallis test; Matrix Metalloproteinase 9; Proteins; Proteolysis; Radiation therapy; Radiotherapy; Resin Cements; Scanning microscopy; Teeth; Tumors; Zymography; United States > US; Germany; Endogenous enzymatic activity; Head and neck cancer; Zymography; Radiotherapy
• ISSN: 0300-5712; 1879-176X
• DOI: 10.1016/j.jdent.2020.103429

The present study investigated the effects of in vitro and in-vivo radiotherapy on endogenous enzymatic activity in dentin using gelatin zymography and in-situ zymography. Gelatin zymographic assays were performed on protein extracts obtained from dentin powder of sound non-irradiated (NRT), in vitro irradiated (VTRT) and in vivo irradiated (VIRT) human teeth. Their proteolytic activities were quantified using band densitometric evaluation. For in-situ zymography, dentin specimens from NRT, VIRT and VTRT were covered with fluorescein-conjugated gelatin and examined with confocal laser-scanning microscopy. Fluorescence intensity emitted by the hydrolyzed fluorescein-conjugated gelatin was quantified and statistically analyzed. In-situ zymography data were statistically analyzed using Kruskal-Wallis ANOVA and Dunn’s multiple comparison procedures (α = 0.05). No difference between in vitro and in vivo radiotherapy treatment was found. Both VTRT and VIRT groups showed increase in MMP-9 expression when compared to NRT group. Significant increases (p < 0.05) in gelatinolytic activity (26 % for VTRT; 55 % for VIRT) were observed when compared to the NRT group. Radiotherapy increase endogenous enzymatic activity in non-restored dentin.