ABSTRACT
PURPOSE: The alpha-melanocyte-stimulating hormone (alpha-MSH) has been shown to interact with various cells of the immune and inflammatory system and down-regulate either the production or the action of the pro-inflammatory cytokines. In this study, we investigated the potential of alpha-MSH on preventing pancreatic islet cell from death and dysfunction by inflammatory cytokines released from peripheral blood mononuclear cells (PBMCs) in rat. METHODS: Rat pancreatic islets were co-cultured with PBMCs, stimulated by phorbol myrstic acid and ionomycin. alpha-MSH was treated to PBMCs for 2 hours before co-culture. Viability and apoptosis of islets were observed by MTT and FACS. Inflammatory cytokines and nitric oxide (NO) were measured. Insulin release from islet co-cultured with mononuclear cells was checked for the islet function. RESULTS: In comparison to control group, viability of islets with alpha-MSH treated mononuclear cells was increased and apoptosis was reduced significantly. Inflammatory cytokines such as TNF-alpha and IL-1beta were reduced in alpha-MSH-treated group. NO production in alpha-MSH-treated group was decreased. Insulin secretory function of islet was recovered in condition of alpha-MSH treatment. CONCLUSION: This study demonstrates that alpha-MSH protects cell death and preserves the secretory function of pancreatic islet cells from the pro-inflammatory reaction of mononuclear cells, and may have the potential to improve the graft survival in clinical islet transplantation.