| Objective：To study the effects of different use of time of magnesium sulfatethat used on pregnant rat and fetal rat of preeclampsia rat model, and theexpression of both the （MAP-2）mRNA and（caspase-3）mRNA, and themechanism of action of hippocampus of fetal brain.Methods: Dividing the pregnant SD rats to five groups: normal pregnant controlgroup, preeclampsia model group,1-day magnesium sulfate treatmentgroup,2-day magnesium sulfate treatment group and4-day magnesium sulfatetreatment group,there were6rats in each group. Except for the normal pregnantcontrol group,the pregnant rats in the other four groups were given low doselipopolysaccharides（1g/kg）to induce them to copy preeclampsia rat model inthe14th day of their pregnancy.The treatment groups had been treated bymagnesium sulfate for1day,2days and4days respectively,and observing itsinfluence on blood pressure and urine protein of pregnant rats.The caesareanbirth purification made in the20th day of pregnancy of the treatment groups,andmeasuring the length and weight of the newborn mice. And then the placenta tissue and the brain tissue of fetal rats were fixed., and observing the histologicchanges through HE(hematoxylin-eosin) staining of placenta in each group.andthe the neuron apoptosis of these tissue were tested by TUNEL method.Theexpression of MPA-2mRNA and caspase-3mRNA of fetal hippocampus in eachgroup were measured by RT-pPCR.Results:（1）On day15of pregnancy,except for the normal pregnant group,thesystolic pressure of the other4groups increased30mmHg,Compared with thebasic systolic pressure of themselves,with statistical significance（P<0.05）.Theblood pressure of preeclampsia model group increased and last until they gavebirth.There is a measurable reduction in the blood pressure of the groups treatedby magnesium sulfate when they were given magnesium sulfate. The bloodpressure of2-day magnesium sulfate treatment group and4-day magnesiumsulfate treatment group decreased obviously compared with the modelgroup,with statistical significance （P<0.05）.Comparison between2-daymagnesium sulfate treatment group and4-day magnesium sulfate treatmentgroup had no statistical significance（P>0.05）.The blood pressure of normalpregnant control group had little change.(2)On day15of pregnancy,except forthe normal pregnant group,the levels of the24-hour proteinuria of the other4groups were higher more than2times the basic pressure, and the comparisonwith he normal pregnant group was of statistics significance（P<0.05）.(3)Thecomparison of birth quotas such as length and weight in different groups had nostatistical significance(P>0.05).(4)The preeclampsia model group showedplacental inflammatory changes such as baseband inflammatory cell infiltration,labyrinth zone tissue nuclear fragmentation and fibrin deposition by examinationof the pathology.The pathological changes mentioned above was evidently slightwhen they came to all the magnesium sulfate treatment groups. The differences between these treatment groups were significant.(5)TUNLE tests showed thatthe numbers of apoptosis in fetal hippocampal CA1region of1-day magnesiumsulfate treatment group,2-day magnesium sulfate group and4-day magnesiumsulfate group were markedly less than that of model group,with statisticalsignificance（P<0.05）.And the effects of treatment of the2-day magnesiumsulfate group and4-day magnesium sulfate group were better than the1-daymagnesium sulfate group,with statistical significance (P<0.05).However, therewas no statistical significance in comparison between2-day treatment group and4-day treatment group(P>0.05).(6)The expression of MAP-2mRNA decreasedwhen the preeclampsia model group,1-day magnesium sulfate treatmentgroup,2-day magnesium sulfate treatment group and4-day magnesium sulfatetreatment group compared with the normal pregnancy control group, withstatistical significance(P<0.05). Compared with the model group, the expressionof MAP-2mRNA of all the magnesium sulfate treatment groups increased,with statistical significance(P<0.05).And the expression of MAP-2mRNA of the2-day magnesium sulfate treatment group and4-day magnesium sulfatetreatment group were higher than the1-day magnesium sulfate treatmentgroup,with statistical significance (P<0.05).However,the comparison betweenthe2-day magnesium sulfate treatment group and4-day magnesium sulfatetreatment group had no statistical significance(P>0.05).(7)The expression ofcaspase-3mRNA of hippocampus of the newborn mice in the preeclampsiamodel group,1-day magnesium sulfate treatment group,2-day magnesiumsulfate treatment group and4-day magnesium sulfate treatment group werehigher than the normal pregnancy control group,with statistical significance(P<0.05).The expression of caspase-3mRNA of groups treated with magnesiumsulfate was less than the model group,with statistical significance (P<0.05).The expression of caspase-3mRNA of2-day magnesium sulfate treatment group and4-day magnesium sulfate treatment group was less than1-day magnesiumsulfate treatment group,with statistical significance (P<0.05).However,thecomparison between the2-day magnesium sulfate treatment group and4-daymagnesium sulfate treatment group had no statistical significance(P>0.05).Conclusions:(1)The low doses of lipopolysaccharides could successfully copythe preeclampsia rat model,caused corresponding manifestations such ashypertension, albuminuria and placental pathology.(2)Magnesium sulfate has acertain therapeutic effect on pregnant rats of preeclampsia,playing a role oflowering the blood pressure, and improving the function of placenta, with noobvious side effects.(3)Magnesium sulfate has a certain therapeutic effect onfetal brain preeclampsia,and its protection mechanism is suppose to be relevantto up-regulating the expression of MAP2mRNA of fetal brain anddown-regulating the expression of caspase-3mRNA.(4)The curative effect ofthe2-day magnesium sulfate treatment group is better than that of the1-daymagnesium sulfate treatment group and the4-day magnesium sulfate treatmentgroup. |
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