TESTING
environment. With this recommendation in mind, HVE tissues maintained in culture for 11 days were used to further evaluate their relevance as an in vitro tool to assess the risk of topically applied hazardous chemicals.
Viability assay Irritant and corrosive substances cause harmful cell damages at the site of contact, reducing cell viability and initiating a protective inflammatory reaction. In vitro, cellular activity and viability is evaluated by a capacity to convert MTS (3-(4,5-dimethylthiazol-2-yl)-5- (3-carboxymethoxyphenyl)-2-(4-sulfophenyl)- 2H-tetrazolium) into a blue formazan salt, while inflammatory responses are detected by the quantification of inflammatory cytokines released by injured cells. In order to validate the suitability of the 3D HVE model as an in vitro tool to assess the risk of hazardous chemicals, its responsiveness to Benzalkonium chloride (BZK) and Triton X100 (Tx100) has been defined first by a viability MTS assay. BZK and Triton X100 are toxic agents causing deleterious impact on the environment and human health. BZK is commonly used at 0.02% as a
preservative in various personal care solutions, with described adverse effects on human tissues.7
Tx100, also known as octylphenol
ethoxylate, is commonly used around 0.1% as an emulsifier in personal care products, with proven cytotoxic effect on mammalian cell lines.8 The impact of BZK 0.02% and Tx100
0.1% on the viability of the epithelial cells was evaluated by an MTS colorimetric assay after a 24 hours treatment on top of the HVE. Topical applications were performed by the use of a nylon mesh that ensures the complete spreading and equal repartition of chemical solutions on the surface of 3D models. Besides the untreated tissue control, a
placebo solution applied by a similar route was used as a negative control condition to evaluate the impact of the mesh application route on the viability of the model. Spectrophotometric quantifications revealed a statistical reduction of the metabolic activity under BZK and Tx100 treatments, compared to untreated and placebo tissues (Figure 3). The absence of a statistical difference
between the untreated HVE and the placebo confirmed that a nylon mesh can be used to apply compound on top of the 3D model without impacting its viability. Taken together, those data comforted on the responsiveness of the 3D HVE model to hazardous chemicals and on its use to evaluate the viability of vaginal tissues after topical application of irritant and corrosive products.
Inflammatory response to chemical threats Irritation often triggers inflammation as a natural response to physical injuries or chemical exposure. Therefore, to correlate the observed loss of viability to an inflammatory status, a complementary quantification of cytokine
77
biomarkers was conducted from HVE treated with BZK or Tx100. Given the central role of Interleukin 1 beta
(IL-1β) in recruiting immune cells to mediate inflammation at infectious site,9
this biomarker
was selected to evaluate the response of HVE to the two cytotoxic agents. The concentration of IL-1β released into the
culture media of HVE treated with BZK 0.02% and Tx100 0.1% from day 11 to day 12 of air/ liquid culture was quantified by a specific ELISA assay. IL-1β was also quantified from the culture media of HVE treated with a placebo solution to evaluate the impact of the topical application on the inflammatory status. As expected, the release of IL-1β was
statistically increased in HVE treated for 24 hours with BZK 0.02% or with Tx100 0.1%, compared to untreated and placebo tissues (Figure 4). Combined to the previous observation of a loss of viability following BZK and Tx100 stimuli, the IL-1β quantification confirmed the responsiveness of the HVE model to chemical threats and therefore its use as a reliable in vitro tool to reflect physiological changes and biochemical reactions induced in natural human vaginal epithelium submitted to external stressors.
Conclusion The present study reports a new 3D vaginal model that recapitulates key anatomical and biochemical features of the natural basal vaginal epithelium. This in vivo-like model displayed the expected cellular responses to
www.personalcaremagazine.com
November 2025 PERSONAL CARE
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107
