Intraplantar injection of sialidase reduces mechanical allodynia during inflammatory pain

Sialic acids are highly charged glycoresidues that are attached to glycoproteins or glycosphingolipids, and they are associated with various biological functions. Gangliosides, sialic acid-containing glycosphingolipids, are abundant in neural tissues and play important roles in the nervous system. Previous studies revealed that peripheral gangliosides are involved in nociceptive behavior and hyperalgesia. These observations prompted us to determine whether the sialic acid-cleaving enzyme sialidase affects pain signaling. Intraplantar injection of sialidase reduced mechanical allodynia during complete Freund's adjuvant-induced inflammation. We also found that ganglioside induces mechanical allodynia in naïve mice. These results suggest that sialyl conjugates in subcutaneous tissues modify allodynia.