Investigation on the effects of Salmonella enterica Subsp enterica serovar Typhimurium on the apoptosis/necrosis of avian macrophage-like monocytes

Introduction and Objectives: Salmonella enterica Subsp enterica serovar Typhimurium (SEST) is one of the most important serovars of the genus Salmonella in human and animals. Because of its intracellular tropism, monocytes/macrophages are pivotal in killing of Salmonella serovars; they are also responsible for transport of SEST to extra-intestinal organs. Study on the mechanistic. To see the mechanistic effects of the SEST on the apoptosis of avian innate immune cells, specially homogeneous macrophage-like monocytes (MLMs). Materials and Methods: The MLMs were isolated from peripheral blood mononuclear cells of many healthy broilers. The MLMs were then divided in two groups: control (without SEST) and treatment (challenged with SEST clinical isolates) groups. Cellular-molecular damage caused by SEST in MLMs was assessed with bioluminescence [(BL), specific method measuring caspases activity and intracellular ATP contents] and flow cytometry (specific method for measuring apoptosis/necrosis). Results: Results of BL-based apoptotic assays revealed higher caspases 3/7 and 9 activity (BL intensity). Furthermore, a significant diminished intracellular ATP content (BL intensity) was observed. The results of flow-cytometry based necrosis of the MLMs cell revealed stable the MLMs in both SEST-treated MLMs and non-treated/control, although slightly more necrotic MLMs was observed in SEST-treated MLMs compared to the non-treated/ctrl counterparts. Conclusion: The results herein indicate that SEST weakens MLMs particularly through caspases activation/apoptosis. These findings can open a new window on the molecular aspect of Salmonella-macrophage interactions and immunopathology/pathogenicity of salmonellosis in animals especially chickens.

Keywords:

Apoptosis , Avian macrophages , Bioluminescence , Flow cytometry , Salmonellosis , Salmonella enterica Subsp enterica serovar Typhimurium.