HPLF were preincubated for 30 min with exogenous GSH and then treated with TEGDMA (2.5 mM) with/without GSH (0.5-2.5-5 mM) for the following incubation exposure types: 6 h (GI); 6 h followed by 18 h recovery time in presence (GII) or absence (GIII) of exogenous GSH; 24 h without recovery time (GIV). TEGDMA-cytotoxicity and intracellular glutathione were assessed by Hoechst 33342 and monobromobimane (MBBr) assays. Data were statistically analyzed with Bonferroni ANOVA (p < 0.05).
Preincubation with exogenous GSH increased the intracellular GSH-concentration. TEGDMA was cytotoxic at all treatment times except at 6 h (GI) (94 卤 7%of control). In GII the treatment with TEGDMA alone (59 卤 7%) showed no different results to cultures exposed to TEGDMA and GSH. Exogenous GSH had no effect on the TEGDMA-induced cytotoxicity also in the GIII and GIV. Thus, a combined incubation with GSH did not prevent the cytotoxicity of TEGDMA, despite of a significant increase of intracellular GSH-concentration in the presence of exogenously supplied GSH.
The glutathione-decreasing effect of TEGDMA is not the major cause of TEGDMA-induced cytotoxicity, indicating more complex mechanisms, which are causative for TEGDMA-cytotoxicity in HPLF.