Melatonin inhibits astrocyte activation in periventricular white matter via NF-κB pathway / 中华急诊医学杂志

ABSTRACT

Objective:To investigate the effect of melatonin (MEL) influence on lipopolysaccharide (LPS)-induced long-term anxiety-like behavior and activation of astrocytes in septic neonatal rats.Methods:Sprague-Dawley rats were randomly(random number) assigned to the control group, LPS group and LPS+MEL group. Sepsis model was intraperitoneally injected with LPS (1 mg/kg), and neonatal rats in the MEL group were administered with MEL (10 mg/kg) 30 min after LPS injection. At different time points after injection, rats in each group were divided into three subgroups 3 d, 7 d and 28 d. The expression of GFAP and TNF-α in the corpus callosum was detected by immunofluorescence staining and Western blot. Open-field test was applied to observe anxiety-like behaviors. In vitro, cultured neonatal SD rat astrocytes were divided into the control group, LPS group, LPS+MEL group, and LPS+MEL+luzindole group. Immunofluorescence staining was used to observe the expression of GFAP and TNF-α. Expression of GFAP, TNF-α, p-NF-κBp65, NF-κBp65 protein in astrocytes were assessed by Western blot. RT-qPCR was used to investigate the mRNA expression of GDNF and BDNF. One-way ANOVA and two-way ANOVA were used for comparison of multiple groups of variables. A P<0.05 was considered statistically significant. Results:LPS reduced the duration of movement in the central area and distance in the central area/total distance in open-field test, while melatonin evidently reversed the LPS-induced anxiety-like behavior. Compared with the LPS group, the expressions of GFAP and TNF-α were significantly decreased in the corpus callosum at 3 d and 7 d in the MEL group ( P< 0.05). Compared with the LPS group, MEL could significantly decrease the expression of GFAP, TNF-α and p-NF-κBp65 in astrocytes ( P< 0.05), which could be blocked by Luzindole. In addition, compared with the LPS group, MEL pretreatment could reverse the down regulation of GDNF and BDNF induced by LPS ( P<0.05). Conclusions:MEL can relieve LPS-induced long-term anxiety-like behavior in septic neonatal rats. The mechanism may be related to the inhibition of astrocyte activation and inflammatory reaction through NF - κ B pathway.