Effect of local autonomic denervation on in vitro responsiveness of lymphocytes from rat submaxillary lymph nodes

Abstract

The local autonomic denervation of rat submaxillary lymph nodes was achieved by a unilateral sympathetic superior cervical ganglionectomy and/or the unilateral section of chorda tympani (that resulted in ipsilateral parasympathetic decentralization of the submandibular territory). This study was performed to determine: (1) whether local sympathetic and/or parasympathetic denervation of rat submaxillary lymph nodes brought about changes in lymph node cellularity, natural killer activity and lipopolysaccharide (LPS)- and concanavalin A (Con A)-induced cell proliferation in Freund's adjuvant-injected rats; (2) whether the effect of the immunosuppressive drug cyclosporine in rat submaxillary lymph nodes was affected by a single or combined unilateral ganglionectomy plus decentralization. A unilateral ganglionectomy, or the combination of ganglionectomy plus decentralization, performed 7 days earlier, decreased significantly cellularity in ipsilateral submaxillary lymph nodes, while a unilateral decentralization failed to affect it. Natural killer activity increased ipsilaterally after ganglionectomy or decentralization, and decreased after the combined surgical procedure. LPS-induced cell proliferation augmented significantly after ganglionectomy or decentralization, while Con A-induced T lymphocyte proliferation remained unaffected. In the sham-operated side, cyclosporine decreased submaxillary lymph node cell number and natural killer activity, while it increased the proliferative response to LPS. The depressive effect of cyclosporine on lymph node cellularity was no longer observed in ganglionectomized or decentralized lymph nodes, but was found after the combined surgical denervation. Decentralization, or decentralization plus ganglionectomy, blunted the depressive effect of cyclosporine on natural killer activity. The stimulatory effect of cyclosporine on lymphocyte proliferation induced by LPS was reversed both by ganglionectomy or by decentralization and was suppressed by the combined surgical procedure. Neither treatment affected Con A-induced proliferation of T lymphocytes. The results further indicate that an appropriate sympathetic and parasympathetic local environment may be needed for immunomodulation, as well as for cyclosporine activity in lymphoid tissue.