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

Objective 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. Material and Methods 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. Results Colony-forming units and viability (OD 450 nm) 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 p21 gene 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). Conclusion 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.

Automated summary

Cannabis and cigarettes smoke were found to induce DNA damage and cellular dedifferentiation in GF/G-MSCs of never smokers, negatively affecting cellular proliferation and viability; meanwhile, EC aerosol showed significantly lower impact on these properties.