Cytotoxicity of 1,4 butanediol diglycidyl ether associated or not with hyaluronic acid in human fibroblasts

Introduction: The half-life of hyaluronic acid in the skin is only a few days, so it is stabilized by cross-linking with 1,4-butanediol diglycidyl ether (BDDE). However, BDDE may be toxic and cause hypersensitivity reactions. Aim: This study evaluated the cytotoxicity of different concentrations of BDDE, with or without hyaluronic acid, on human fibroblasts. Methods: Human gingival fibroblasts were isolated and added at 1x104 cells per well in 96-well plates. For cytotoxicity analysis, BDDE was tested at concentrations of 1, 2, 20, 70, and 100 ppm relative to the hyaluronic acid hydrogel in the culture medium. Another set was composed of the same amounts of BDDE dissolved only in the culture medium, resulting in concentrations of 0.2, 0.4, 4, 14, and 20 ppm. Control groups included cells in culture media only (positive control), cells in hyaluronic acid without BDDE, and cells with 20% methanol (negative control). Cytotoxicity was measured using the MTT assay at 24 hours and 7 days (n = 3, in duplicate). Cell viability was calculated relative to the positive control group (cells in culture medium only). Data were analyzed using one-way ANOVA and the Tukey test (α = 0.05). Results: All groups were not cytotoxic after 24 hours (p > 0.05). However, at 7 days, 20 ppm BDDE without hyaluronic acid (p<0.05) and 70 and 100 ppm BDDE with hyaluronic acid were cytotoxic (p<0.01). Conclusion: The BDDE cross-linker showed late cytotoxicity (7 days) to gingival fibroblasts at high concentrations.