Exosomes are small (40-150 nm) membrane vesicles of endocytic origin that are found in bodying fluids, and supporting their role in intercellular communication. Although recent studies have demonstrated that various biomarkers involved in the extent of pain from the serum exosomes, the effects of exosomes on the onset and progression of pain have not been elucidated. The objective of this study was to examine the effects of serum exosomes in mice with PSL on nociceptive responses induced by 0.5% formalin.
We have confirmed that the i.t. injection of serum exosomes from PSL mice or sham-operated mice transferred into the normal mice did not show any spontaneous nociceptive responses. However, 0.5% formalin-induced nociceptive response was significantly enhanced by i.t. pretreatment with serum exosomes isolated from PSL mice but not from sham mice. In addition, we digested the exosomes isolated from PSL with trypsin to obtain the ‘‘surface protein shaved'' exosomes. The surface protein shaved PSL exosomes were ineffective on formalin-induced response.
Our data indicate that the surface protein of exosomes in mice with PSL may play an important role in enhancing nociceptive responses.