Triclosan, cytotoxicity, mode of action, and induction of apoptosis in human gingival cells in vitro

Abstract

The in vitro cytotoxicology of triclosan, the active ingredient in some mouthrinses and dentifrices used in the prevention and treatment of gingivitis and plaque, was studied using the Smulow-Glickman (S-G) human gingival epithelial cell line. The 24 h midpoint cytotoxicity value was 0.05-0.06 mM triclosan as assessed with the neutral red (NR) assay. Triclosan is used in dentifrices in combination with either zinc citrate or sodium fluoride (NaF). The sequence of potencies of these test agents, as assessed with the NR assay, was triclosan>zinc citrate>>NaF; combinations of triclosan + zinc citrate and triclosan + NaF were additive in their toxicities. Damage to the integrity of the plasma membrane, as assessed by the leakage of lactic acid dehydrogenase during a 3-h exposure, was initially evident with 0.1 mM triclosan. When exposed to triclosan for 3 d, a lag in the growth kinetics of the S-G cells was first observed at 0.01 mM triclosan. A reduction in attachment of S-G cells to dentin chips, previously exposed to triclosan for 1 h, was noted at 0.25 mM triclosan and greater. Triclosan-induced cell death was apparently by apoptosis, as noted by fluorescence microscopy and DNA agarose gel electrophoresis of extracted oligonucleosomal fragments.

Immunotoxic effects of triclosan in the clam Ruditapes philippinarum

“…These results are consistent with those of other studies that have investigated the effect of TCS on cell proliferation in other species or cell types. For example, limited cell growth occurs in the Smulow-Glickman (S-G) human gingival epithelial cells that are exposed to TCS for 3 days (Zuckerbraun et al 1998).…”

The Peritoneal Explant Test for Evaluating Tissue Tolerance to Mouthrinses

“…While the Smulow-Glickman test measures the damage of plasma membrane via leakage of lactic acid dehydrogenase [16] or viable cells per unit area remaining after exposure [17] , the human gingival fibroblasts test further measures the proliferation directly [18] or indirectly via DNA-intercalating fluorescent stain H33342 [19] . These cell lines are based on biopsies, which are limited in providing materials and are an ethical issue.…”

Triclosan in Toothpaste, Is There Any Real Risk for the Health?

“…En células animales, el TCS produce cambios en la morfología, disminución de actividad mitocondrial, de actividades metabólicas y de proliferación. Puesto que el TCS se ha empleado desde hace 3 décadas en formulaciones para higiene oral, los primeros estudios reportando su citotoxicidad fueron hechos sobre líneas celulares derivadas de encía humana (20,21). En la línea celular epitelial de encía humana Smulow-Glickman, se observó que el TCS redujo la integridad de la membrana celular a una concentración (C.C.)…”

“…de 0.05 mM redujo la masa citoplasmática y provocó vacuolización y apoptosis mientras que la proliferación celular se vio afectada con una C.C. de 0.01 mM (21), estas observaciones sugirieron que el TCS puede tener efectos adversos a largo plazo (21). A pesar de la evidencia temprana, sólo en los últimos años se ha enfatizado en investigar la toxicidad del TCS en distintas líneas celulares y modelos animales.…”