Investigating the effects of blue light on cells of the periodontium

Gait-Carr, Edward 2023. Investigating the effects of blue light on cells of the periodontium. PhD Thesis, Cardiff University. Item availability restricted.

	PDF - Accepted Post-Print Version Restricted to Repository staff only until 16 May 2025 due to copyright restrictions. Download (6MB)
	PDF (Cardiff University Electronic Thesis and Dissertation Form) - Supplemental Material Restricted to Repository staff only Download (108kB)

Abstract

In recent years, UV-free blue light has been proposed to supplement current treatment modalities for periodontal disease, owing to its antimicrobial properties which are specific to periopathogenic bacterial species. However, little work has sought to investigate the influence of blue light upon periodontal support tissues. The aim of this study was to investigate discrete molecular targets of 457 nm blue light in primary human gingival fibroblasts (pHGFs) and primary human gingival keratinocytes (pHGKs), with a view to identify cellular responses and proteinaceous and genetic targets which characterise photobiomodulation (PBM) in these cell types. pHGFs or pHGKs received doses of 457 nm blue light ranging from 3 J/cm2 to 90 J/cm2 , prior to experimental assay. pHGFs displayed reductions in cell health, while pHGK proliferation and metabolic activity was enhanced following irradiation (3 – 90 J/cm2 ). Treatment of pHGFs with blue light (3 – 60 J/cm2 ) induced significant generation of reactive oxygen species (ROS), which was inhibited by the presence of an ROS scavenger, N-acetyl cysteine (NAC). Comparable trends in ROS generation and scavenging were also evident in pHGKs irradiated with blue light, however these responses were not significant. pHGFs displayed subtle stimulation of antioxidant responses, while pHGKsshowed no change relative to untreated controls. Analyses of extracellular matrix genes and growth factor secretion from pHGFs revealed significant increases in hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and matrix metalloproteinase 1 (MMP-1), in response to blue light. Presence of NAC during irradiations resulted in inhibition of MMP-1 gene upregulation, thereby correlating generation of ROS with subsequent gene expression and protein secretion. Preliminary insights into use of ex vivo rodent gingival tissue to model PBM responses showed promise, with no detrimental effects observable after a single high fluence dose (60 J/cm2 ), compared to untreated samples. In conclusion, pHGFs and pHGKs displayed differential responses to 457 nm blue light. These findings corroborate current literature, which point toward cell type specific PBM responses. Importantly ROS was established as a PBM mechanism through which secondary cellular responses are mediated. Additionally, growth factors associated with gingival wound healing and tissue remodelling were also influenced by blue light treatments. These findings provide ii novel evidence that UV-free wavelengths of blue light have the potential to confer preferential effects upon gingival tissues and, as such, be used as adjunctive or prophylactic treatments in the management of periodontal disease.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Dentistry
Subjects:	R Medicine > RK Dentistry
Date of First Compliant Deposit:	16 May 2024
Last Modified:	16 May 2024 15:40
URI:	https://orca.cardiff.ac.uk/id/eprint/168972

Actions (repository staff only)

Edit Item