Gingival Retraction Procedure is Associated with Increased Gene Expression of TNF-α and TNF-α Receptors: A Pilot Study
Published: 2020-12-22
Page: 166-173
Issue: 2020 - Volume 3 [Issue 2]
Gang Hu
Department of Periodontics, Rutgers School of Dental Medicine, Rutgers University, 110 Bergen St, Newark, NJ 07103, USA.
Andrew Sullivan
Department of Periodontics, Rutgers School of Dental Medicine, Rutgers University, 110 Bergen St, Newark, NJ 07103, USA.
Zaoling Hu
Department of Restorative Dentistry, Rutgers School of Dental Medicine, Rutgers University, 110 Bergen St, Newark, NJ 07103, USA.
Saul Weiner *
Department of Restorative Dentistry, Rutgers School of Dental Medicine, Rutgers University, 110 Bergen St, Newark, NJ 07103, USA. and Department of Biomedical Engineering, Stevens Institute of Technology, 507 River Street, Hoboken, NJ 07030, USA.
*Author to whom correspondence should be addressed.
Abstract
Background: Gingival retraction procedure (GRP), a regularly practiced clinical procedure, displaces the gingiva from around the tooth, temporarily. It has been reported that increased tumor necrosis factor-alpha (TNF-α) levels in gingival crevicular fluid (GCF) were observed even after 30 days following GRP. TNF-α is a pro-inflammatory cytokine found in periodontally-diseased tissues and is associated with loss of connective tissue and bone. The effects of (TNF-α) are tightly regulated by TNF receptor-1 (TNFR1) and 2 (TNFR2). The object of these experiments was to test the hypothesis that up-regulation of TNF-α expression is associated with increased gene expression of its receptors, (i.e., TNFR1 and TNFR2).
Methods: In a GRP rat model, the gingival Index (GI) was recorded, the expressions of TNF-α, and associated genes TNFR1, and TNFR2 in gingival tissue were measured and hematoxylin and eosin (H&E) histological examination was performed.
Results: Expression of TNF-α and TNFR2-related genes demonstrated similar profiles. Both paralleled the profile of the GI. They peaked at day 1 after GRP, and were reduced but still remained at a higher level as compared to sham control at day 3 after GRP, and then returned close to normal at day 7. On the other hand, TNFR1 gene expression peaked at day 3 and remained elevated at day 7 after GRP.
Conclusions: The results indicate gene expressions of TNF-α and TNHR2 are closely associated with the time course of the gingival injury from the retraction procedure, while TNFR1 gene expression may have further long-term effects.
Keywords: TNF-α, gingival retraction, TNHR1, TNHR2, inflammation.