Fig. 3. Alteration in cytosolic Ca²⁺ homeostasis induces mitochondrial dysfunction triggering M. fortuitum-induced HKM apoptosis.

a The alteration in ΔΨm was studied using JC-1 dye. HKM pre-treated with or without indicated inhibitors were infected with M. fortuitum and at 12 h p.i. ΔΨm studied by confocal microscopy ( × 40). b MPT formation was studied using DiOC₆ dye. HKM were infected with M. fortuitum for indicated time period and the relative fluorescence intensity of DiOC₆ plotted. c HKM pre-treated with or without indicated inhibitors were infected with M. fortuitum and the cytosolic translocation of cytochrome c studied by immunoflurescence using TRITC- tagged secondary antibody at 24 h p.i. The nuclei were stained with DAPI. The images are representative of three independent experiments and observed under confocal microscope ( × 40). Vertical bars represent mean ± SE (n = 3).*P < 0.05, compared to HKM. HKM, control head kidney macrophage; HKM + MF, HKM infected with M. fortuitum; HKM + RR + MF, HKM + CsA + MF, HKM + BAPTA/AM + MF, HKM + Dant + MF, HKM + 2-APB + MF, HKM pre-treated with RR, CsA, BAPTA/AM, Dant, 2-APB respectively and infected with M. fortuitum