Interleukin-6 expression and regulation in rat enteric glial cells

As yet, little is known about the function of the glia of the enteric nervo us system (ENS), particularly in an immune-stimulated environment. This pro mpted us to study the potential of cultured enteroglial cells for cytokine synthesis and secretion. Jejunal myenteric plexus preparations from adult r ats were enzymatically dissociated, and enteroglial cells were purified by complement-mediated cytolysis and grown in tissue culture. Cultured cells w ere stimulated with recombinant rat interleukin (IL)-1 beta, IL-6, and tumo r necrosis factor (TNF)-alpha, and IL-6 mRNA expression and secretion were assessed using RT-PCR and a bioassay, respectively. Stimulation with TNF-al pha did not affect IL-6 mRNA expression, whereas IL-1 beta stimulated IL-6 mRNA and protein synthesis in a time- and concentration-dependent fashion. In contrast, IL-6 significantly and dose-dependently suppressed IL-6 mRNA e xpression. In summary, we have presented evidence that enteric glial cells are a potential source of IL-6 in the myenteric plexus and that cytokine pr oduction by enteric glial cells can be regulated by cytokines. These findin gs strongly support the contention that enteric glial cells act as immunomo dulatory cells in the enteric nervous system.