IL-6 immunoreactivity changes during aging in the polychaete Ophryotrocha labronica (Polychaeta: Dorvilleidae)

IL-6 is a pleiotropic pro-inflammatory cytokine thought to play a role in age physiology, even if its possible modulation by aging mechanisms has not been fully defined. In this paper, the morpho-functional modifications and IL-6 immunoreactivity during aging in a simple invertebrate model, Ophryotrocha labronica, are reported. The comparison between newly-hatched, juveniles, young adult and 3-month-old females showed significant differences in the nervous and genital systems. There is evidence of nerve cell loss and a decline in oocyte growth and maturation at the gonad level. Immunohistochemistry reveals a different distribution of IL-6-like molecules, and a decreased number of reactive nerve cells in the central nervous system of aged O. labronica associated to the induced morphological modifications.