RESUMO
Objective:To study the effect of melatonin (MEL) on the pyroptosis of hippocampus in neonatal rats with hypoxic-ischemic brain damage (HIBD), and the related mechanism.Methods:The animal model of HIBD was established by the modified Rice method.According to the random number table, a total of 105 Sprague-Dawley (SD) rats aged 7 days were divided into 7 groups (15 rats in each group): sham operation (Sham) group, model (HIBD) group, MEL treatment group (5, 10 and 20 mg/kg), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway inhibitor (LY294002) treatment group and MEL+ LY294002 group.The hippocampus neuronal morphology and the changes of nissl bodies were observed through HE staining and nissl staining.The mRNA expression levels of Nod-like receptor family 3 (NLRP3), apoptosis-associated speck-like protein containing a card (ASC), Caspase-1, gasdermin D (GSDMD), interleukin-1β (IL-1β) and interleukin-18 (IL-18) in the left hippocampus of rats were detected by real-time fluorescence quantitative PCR.The protein expression level of the above indexes and the level of phosphorylated Akt (p-Akt) were measured by Western blot.Results:Compared with the Sham group, the number of cell layers in hippocampal CA1 region in the HIBD group decreased, the cell arrangement was irregular, and there were less nissl bodies.Besides, the mRNA expression levels of NLRP3 (1.98±0.08 vs.0.86±0.13), ASC (1.40±0.12 vs.0.81±0.07), Caspase-1 (1.46±0.10 vs.0.75±0.09), GSDMD (1.35±0.10 vs.0.81±0.10), IL-18 (1.23±0.08 vs.0.23±0.04), IL-1β (1.83±0.09 vs.0.57±0.08) and p-Akt (1.12±0.12 vs.0.54±0.07) in the HIBD group were significant higher than those in the Sham group (all P<0.05). Compared with the HIBD group, there were more cell layers in hippocampal CA1 region of the MEL group (10 mg/kg), the arrangement of cells was more regular, and the number of nissl bodies increased.The mRNA expression levels of NLRP3 (1.04±0.10), ASC (0.91±0.06), Caspase-1 (0.63±0.06), GSDMD (1.01±0.09), IL-18 (0.65±0.05) and IL-1β (0.63±0.10) in the MEL group were statistically significantly lower than those in the HIBD group (all P<0.05). Compared with the MEL group (10 mg/kg), the arrangement of cells in hippocampal CA1 region of the MEL+ LY294002 group was relatively disordered, the nissl bodies declined, the p-Akt protein level (0.87±0.09 vs.1.99±0.27) decreased significantly, and the Caspase-1(p20) protein level (0.85±0.09 vs.0.58±0.09) increased significantly (all P<0.05). Conclusions:MEL may inhibit the hippocampal pyroptosis in neonatal rats with HIBD by activating the Akt signaling pathway, thereby protecting the brain.
RESUMO
Objective To study on the correlation of VEGF,HSP 70,NBNA score and neonatal asphysia. Methods Using ELISA to detect the expression level of VEGF,HSP 70 in mild asphyxia group,severe asphyxia group and control group. The expression level of VEGF ,HSP 70and the correlation between NBNA score and asphyxia were compared. Results The expression levels of VEGF ,HSP 70 in both mild and severe asphyxia groups were significantly statistically higher than the control group(P<0.05). The severe asphyxia group had even higher VEGF,HSP 70 levels than the mild asphyxia group(P<0.05).The expression level of VEGF,HSP 70 are negatively correlated with the 7 th,14 th,28th-day NBNA score (r=-0.712,-0.629,-0.493;r=-0.621,-0.506,-0.016 ;P < 0.05).The area curve(AUC)for VEGF,HSP 70 leves to predicted respectively were 0.873 (95%CI 0.771~0.892,P<0.05)and 0.815(95%CI 0.729~0.871,P<0.05). Conclusions VEGF,HSP 70 lev-els in umbilical cord blood are closely related to neonatal asphyxia.The more severe the asphyxia ,the higher the expression level of VEGF and HSP 70,and the lower the NBNA score.