In vitro evaluation of the effect of the electronic cigarette aerosol, Cannabis smoke, and conventional cigarette smoke on the properties of gingival fibroblasts/gingival mesenchymal stem cells.

Abstract

The current study aimed to evaluate the effect of electronic cigarette (EC) aerosol, Cannabis, and conventional cigarettes smoke on gingival fibroblast/gingival mesenchymal stem cells' (GF/G-MSCs) of never smokers. Human GF/G-MSCs (n=32) were isolated and characterized using light microscopy, flow cytometry, and multilineage differentiation ability. Following the application of aerosol/smoke extracts, GF/G-MSCs were evaluated for cellular proliferation; colony-forming units (CFU-F) ability; cellular viability (using the MTT assay); mitochondrial depolarization using JC-1 dye; and genes' expression of ATM, p21, Oct4, and Nanog. Colony-forming units and viability (OD 450nm) were significantly reduced upon exposure to Cannabis (mean±SD; 5.5±1.5; p<.00001, 0.47±0.21; p<.05) and cigarettes smoke (2.3±1.2 p<.00001, 0.59±0.13, p<.05), while EC aerosol showed no significant reduction (10.8±2.5; p=.05, 1.27±0.47; p>.05) compared to the control group (14.3±3, 1.33±0.12). Significantly upregulated expression of ATM, Oct4, and Nanog (gene copies/GADPH) was noticed with Cannabis (1.5±0.42, 0.82±0.44, and 1.54±0.52, respectively) and cigarettes smoke (1.52±0.75, 0.7±0.14, and 1.48±0.79, respectively; p<.05), whereas EC aerosol caused no statistically significant upregulation of these genes compared to the control group (0.63±0.1, 0.31±0.12, and 0.64±0.46, respectively; p>.05). The p21gene was not significantly downregulated in EC aerosol (1.22±0.46), Cannabis (0.71±0.24), and cigarettes smokes (0.83±0.54) compared to the control group (p=.053, analysis of variance). Cannabis and cigarettes smoke induce DNA damage and cellular dedifferentiation and negatively affect the cellular proliferation and viability of GF/G-MSCs of never smokers, whereas EC aerosol showed a significantly lower impact on these properties.