Effect of melatonin on exosomal dynamics in bovine cumulus cells

In this study, the effects of melatonin were investigated on the exosome release from bovine cumulus cells after 7 days. Cells were randomly allocated into three groups as follows; Control, 0.1 nM, and 0.1 mM Met groups. The physicochemical properties of exosomes such as size and zeta potential were measured by the dynamic light scattering. Both scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to characterize exosome morphology. The effect of melatonin on cell viability was studied using an MTT assay. The expression of exosome markers like Alix, CD63, Rab27a, and Rab27b was monitored using real-time PCR analysis. We also investigated fatty acid composition by the gas chromatography method. TEM and SEM confirmed typical exosome's morphology. By increasing the concentration of melatonin, the viability of cumulus cells was significantly increased compared to the control group (p < 0.05). These changes coincided with the significant reduction of exosome diameter (p < 0.05). Zeta potentials of exosomes were not changed after treatment with 0.1 nM, and 0.1 mM melatonin. Compared to the control cells, 0.1 mM melatonin increased the expression of mRNA for Rab27b whereas suppression of CD63 was found simultaneously (p < 0.05). The expression of Alix and Rab27a was not changed in groups that received 0.1 nM, and 0.1 mM melatonin. Melatonin increased the percent of unsaturated fatty acids such as Arachidonic acid, Oleic acid, and Linoleic acid. These data showed that melatonin could change the exosomal dynamics in bovine cumulus cells.