Cytotoxicity and apoptosis induction by e-cigarette fluids in human gingival fibroblasts

Clin Oral Investig. 2016 Apr;20(3):477-83. doi: 10.1007/s00784-015-1537-x. Epub 2015 Aug 4.


Objectives: Electronic cigarettes (e-cigarettes) are generally acknowledged as a safer alternative to the use of combusted tobacco products. Nevertheless, there are increasing conflicting claims concerning the effect of these novel industrial products on the health of e-cigarettes users. The aim of this work was to investigate the effects of the liquids of e-cigarettes on human gingival fibroblasts (HGFs) and to compare the effects of nicotine-containing fluid to the fluid itself.

Materials and methods: HGFs were treated with different concentrations (0-5 mg/mL) of fluids of e-cigarettes for different times (0-72 h) and cytotoxicity was analyzed by MTT assay. Fluids were administered also after being vaped (e.g., warmed into the cartomizer). Apoptosis occurrence and Bax expression were evaluated by flow cytometry; ROS production was analyzed by fluorescence optical microscopy.

Results: Both nicotine-containing and nicotine-free fluids induced an increased ROS production after 24 h, along with an increased Bax expression, followed by apoptosis occurrence after 48 h of exposure.

Conclusions: The cytotoxicity exerted on HGFs by e-cigarettes fluids is not entirely ascribable to nicotine. Since the e-cigarettes are advertised as a safer alternative to traditional ones, especially for the possibility of "smoking" nicotine-free fluids, further studies are necessary to clarify the mechanism involved in the occurrence of cytotoxicity exerted by such compounds.

Clinical relevance: Our results suggest a role for e-cigarette fluids in the pathogenesis of oral diseases, such as periodontitis.

Keywords: Apoptosis; Bax; Cytotoxicity; Human gingival fibroblast; Reactive oxygen species; e-cigarette.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Electronic Nicotine Delivery Systems / adverse effects*
  • Fibroblasts / drug effects*
  • Flow Cytometry
  • Gingiva / cytology*
  • Gingiva / drug effects*
  • Humans
  • Microscopy, Fluorescence
  • Reactive Oxygen Species / metabolism
  • Risk Factors
  • bcl-2-Associated X Protein / metabolism


  • Reactive Oxygen Species
  • bcl-2-Associated X Protein