Abstract: 　Objective　To explore the changes in plasma melatonin (MT) and glucocorticoid (GC) and the expressions of melatonin receptor 1 (MR1) and glucocorticoid receptor alpha (GR alpha) after neonatal asphyxia. Methods　Full-term asphyxia neonates (22 cases of mild asphyxia, 28 cases of severe asphyxia) hospitalized from May 2014 to December 2015 were selected. Another 50 non-asphyxiated full-term newborns hospitalized with single disease such as infection and jaundice at the same time were selected as the control group. Peripheral blood samples were collected within 24 hours after birth and 7 days after birth, and plasma and mononuclear cells were separated. The plasma MT and GC expression levels were detected by ELISA. Realtime PCR was used to detect MR1 and GRα mRNA expression. Results　The plasma GC concentrations in mild and severe asphyxia group increased significantly within 24 hours after birth, higher than that in control group. In addition, the plasma GC concentration in severe asphyxia group was significantly higher than that in mild group (P<0.05). The concentration of plasma GC in mild and severe asphyxia group decreased on the 7th day after birth (P<0.05) and was significantly lower than that at 24 hours after birth, but it was still higher in the severe asphyxia group than that in mild group; both the mild and severe asphyxia group had higher GC level than that in control group; the differences are statistically significant (P<0.05). Within 24 hours after birth, the plasma MT concentration in severe asphyxia group was lower than that in mild asphyxia group and control group, and there were significant differences (P<0.05). Compared with 24 hours after birth, the concentrations of plasma MT in severe and mild asphyxia groups increased significantly, higher than that in control group on the 7th day, and there were significant differences (P<0.05). The level of GR alpha mRNA expression decreased within 24 hours after birth in severe asphyxia group, but  was increased in the mild asphyxia group, and there were significant differences among the three groups (P<0.05). The expression levels of GRα in both mild and severe asphyxia groups recovered on the 7th days after birth, and there were no significant differences compared with control group (P>0.05). Compared with 24 hours after birth , the expression level of MR1 mRNA in severe asphyxia group increased on the 7th day after birth, higher than that in control group and in mild asphyxia group, and there were significant differences (P<0.05). Conclusions　The stress caused by severe asphyxia exceeds the adaptation range in the newborn, and results in the high expressions of MR1 and endogenous MT.
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