Figure 2

BME26 tick cells tolerate H₂O₂ overexposure compared to other mammalian cell lines. (A–D) Comparison of cell viability was determined using a Neubauer hemocytometer with trypan blue exclusion technique, in four different cell types 24 h after challenge with increasing H₂O₂ concentrations (from 62.5 μM to 1000 μM H₂O₂). (A) Embryonic Rhipicephalus microplus BME26 cell line; (B) embryonic Aedes aegypti Aag2 cell line; (C) BLACK6 mouse macrophage primary culture cells; (D) Rhesus monkey kidney epithelial LLCMK2 cell line. The dotted line (100%) represents untreated control (absence of H₂O₂). (E) BME26 cells viability was measured by MTT assay 24 h after H₂O₂ addition at increasing concentrations ranging from 2.2 mM to 13.2 mM. Insert shows LD₅₀ at approximately 6.02 mM. (F) BME26 cells viability was assessed by MTT assay 2 h, 12 h and 24 h after H₂O₂ addition at 2.2 mM (non-lethal) and 4.4 mM (~LD₂₅) concentrations. (G) BME26 cells morphology was observed under a confocal laser scanning microscope, Zeiss LSM 710. Cytoskeletal architecture (red) and nuclei (blue) were observed using Phalloidin-Texas Red and Hoechst 33342 staining, respectively. White arrows show the filopodia and yellow asterisks show cells with a rounded shape. Scale Bar: 20 µm. The experiments were performed with three independent biological samples in three experimental replicates each, *p < 0.05, **p < 0.01, ***p < 0.001, compared to control in Tukey’s multiple comparisons test.