Abstract: To investigate the effects of melatonin on the proliferation and function of porcine placenta trophoblast cells (pTr), pTr cells were treated with different concentrations of melatonin (0, 10 nmol /L, 100 nmol/L, 1 μmol/L, 10 μmol/L and 100 μmol/L) for 48 hours. The effect of melatonin on the proliferation and function of pTr cells was analyzed by detecting the number of cells, the secretion levels of VEGF, EGF, E2, P4 and the mRNA expression levels of related genes. The results showed that the concentration of 10 μmol/L melatonin significantly promoted the proliferation of pTr (P<0.05). The secretion levels of VEGF, EGF, E2 and P4 were significantly increased (P<0.05). Compared with the blank control group, 10 μmol/L melatonin significantly up-regulated the expression ofMT1,CDK4,SLC2A1,VEGF, andEGFRin pTr cells (P<0.05), and the expression ofVEGFR2,EGF,ESR1, andPGR(P<0.01). In conclusion, 10 μmol/L melatonin could promote the proliferation of pTr cells by directly binding to MT1, or indirectly by regulating the expression ofCDK4andSLC2A1genes. In addition, melatonin might also improve placental function in pigs by regulating the expression of growth factors and their receptors and steroid hormone receptors and promoting the synthesis and secretion of growth factors and reproductive hormones.

Key words: melatonin, porcine placental trophoblast cells, cell proliferation, gene expression