Bovine milk exosomes affected proliferation of macrophages under hypoxia

Exosomes are extracellular vesicles implicated in cell-to-cell communication. The objective was to investigate the effect of exosomes in macrophages under hypoxia. Exosomes were isolated from skim milk using differential centrifugation and was characterized by particle size and exosomal markers TSG101, CD81, and ALIX. The effect of exosomes on macrophages under hypoxia was investigated by assessing proliferation, cytokine and reactive oxygen species (ROS) production, and cell cycle. Exosomes treatment increased the cell viability under hypoxia while ROS production was significantly reduced. The production of TNF-α was not affected by hypoxia alone but increased in a dose-dependent manner in cells treated with exosomes under hypoxic condition. Hypoxia arrested cells in the G0/G1 phase whereas exosome treatment reduced the cell in this phase. Our study found that bovine milk exosomes affect the proliferation of macrophages under hypoxia and are able to reverse the adverse effects of hypoxia on cell viability.