Effects of melatonin on the cytokines production of neonatal cord blood mononuclear cell

Abstract

Objective To investigate the effects of melatonin(MLT)on the cytokines production of neonatal cord blood mononuclear cells(CBMC)in vitro. Methods Ten blood specimens from placenta vena umbilicalis of 10 healthy term delivery newborns were obtained,and 10 healthy adult volunteers'peripheral blood mononuclear cells(PBMC)specimens were taken as controls.CBMC and PBMC suspensions were cultivated in the system without serum and hormone,and then 200 μl PBMC/CBMC suspensions(2 105 cells)were co-cultured with MLT with different concentrations(50 ng/ml,5 ng/ml,500 pg/ml,50 pg/ml)for 72 hours.The concentrations of cytokines including IL-1β,IL-2,IL-4,IL-6,IL-8,IL-12,IFN-γ and TNF-α in the cell supernatant were detected.Results The 500 pg/ml MLT induced secretions of IL-2[(12.18 7.31)pg/ml],IL-6[(2091.08±968.58)pg/ml],IL-8[(2779.04±1168.49)pg/ml],IL-12[(15.29±6.88)Pg/ml]and IFN-γ[(52.22 17.77)pg/ml]of CBMC were more than those of the control group,which were(6.99±4.94)pg/ml,(1017.06±452.60)pg/ml,(1293.33±791.34)pg/ml,(6.84±2.26)pg/ml and(22.24±10.38)pg/ml(P<0.05).Compared with control group[(175.63±62.10)Pg/ml],all concentrations of MLT could inhibit the TNF-α secretion[(24.87 11.21)pg/ml,(18.14±9.44)pg/ml,(31.38±15.28)pg/ml and(28.18±17.35)pg/ml]of CBMC significantly.The 50 ng/ml MLT could induce the PBMC's secretion of IL-2, IL-12, IFN-γ,and inhibit the secretion of TNF-α. The best effect of MLT on CBMC was at the concentration of 500 pg/ml, while that on PBMC was 5 ng/ml. Comparing the best effects of MLT, the levels of IL-12 and IFN-γ of CBMC were higher than those of PBMC, and IL-2 level of CBMC was lower than that of PBMC (P<0.01). Conclusions MLT could promote the cytokine secretion of PBMC and CBMC, and the effects of MLT on IL-12 and IFN-γ secretion of CBMC were stronger than those of PBMC. The results suggested that MLT may contribute to promote the immune function in newborn infants, and provide experimental evidence for clinical application of MLT. Key words: Melatonin; Fetal blood; Leukocytes, mononuclear; Cytokines