Effects of magnesium sulfate on the neuroprotection of hippocampus of fetal rats delivered by experimental rats model of preeclampsia

Objective To explore the effects of magnesium sulfate (MgSO4) on the hippocampal neurons of fetal rats which were delivered by pre-eclampsia (PE) experimental model rats. Methods A total of 18 pregnant Sprague-Dawley (SD) rats were included into this study. They were divided into 3 groups according to different treatment methods: model group (n=6, PE experimental model group without any treatment), treatment group (n=6, 2-day MgSO4 treatment of PE experimental model rats) and control group (normal pregnant rats). Model group and treatment group were given low dose lipopolysaccharides (1 μg/kg) to induce experimental rats model of PE. Treatment group were managed by MgSO4 60~120 (mg/kg·d) for 2 days before the caesarean birth at the 20th day of pregnancy. Hippocampal neurons in CA1 region were analyzed for apoptosis by TUNEL assay. Relative expression levels of cysteine aspartic proteases (caspase)-3 of hippocampus in fetal rats were detected by real-time (RT)-PCR and immunohistochemistry. Results ①There was no significant difference on systolic blood pressure at 13th day during pregnancy among three groups (F=2.876, P>0.05). The systolic blood pressure of model group and treatment group were higher than that of control group on the 15th day during the pregnancy, with significant differences (P<0.05), and the systolic blood pressure of treatment group was lower than than of model group on 19th day during the pregnancy with significant difference (P<0.05). ②There was no significant difference on neuronal apoptosis of CA1 region of hippocampus in rat brains among three groups (F=1 931.4, P<0.05). The number of neuronal apoptosis of CA1 region of neuronal apoptosis in rat brains of model group and treatment group were higher than that of control group (P<0.05), and the number of neuronal apoptosis of CA1 region of neuronal apoptosis in rat brains of treatment group was lower than that of model group (P<0.05). ③ There was no significant difference on the relative expression levels of caspase-3 mRNA of hippocampus in rat brains among three groups (F=1 687.13, P=0.000). The relative expression of caspase-3 mRNA of hippocampus in rat brains of model group and treatment group were higher than that of control group (P<0.05), and the relative expression of caspase-3 mRNA of hippocampus in rat brains of treatment group was lower than that of control group (P<0.05). Conclusions Administration of regular dose of MgSO4 treatment may play a neuroprotective role in the brain of fetal rats who were delivered by experimental rats model of PE and its mechanism may be related to the regulation of fetal brain caspase-3. Key words: Pre-eclampsia; Hippocampus; Apoptosis; Magnesium sulfate; Caspase 3