Co-culture Techniques for Cytotoxicity Assays

Objectives: The aim of this study was to evaluate different co-culture tecniques with human cells and microorganisms, for citotocixity assays.
Methods: Two techniques were evaluated: co-culture with direct interaction betwen cell types and co-culture with cell types separated with transwell membrane. In both techniques, Candida albicans and keratinocytes were grown separately for 24 hours and then kept in contact for an additional 24 hours. After this period, cell proliferation was assessed using Alamar Blue and CytoTox-One. Qualitative and quantitative analyses were performed. Analysis of variance (ANOVA) was applied to the survival percentages of cells compared to the control group (considered as 100% viability), complemented by multiple comparisons using Tukey's test. A 5% significance level was adopted.
Results: According to ISO standards,cell types with direct interaction, were moderately cytotoxic (inhibition between 50 and 75% compared to the control group) to both tests. However, there was no interference in cells metabolism in co-culture with transwell, since no differences were observed between the control group (cultured cells by themselves). This goup was classified as none cytotoxic (inhibition lower than 25% compared to the control group).
Conclusions: According to the findings, transwell membrane allowed an interaction between keratinocytes and Candida, as well as an interaction between its metabolites produced with suitable monitoring without causing damage to the cells.