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Objective To explore the effect of blood-brain barrier disruption on expression of AQP-4,through comparing the cell morphology and the expression of aquaporin-4(AQP-4)of cultured astrocytes in medium with and without fetal bovine serum(FBS). Methods Cerebral cortical astrocytes from female Wistar rats were cultured in serum free medium,DMEM supplement-ed with 10% FBS,and serum free medium supplemented with 10% FBS.Phase contrast microscope was used to detect the cell morphology and cell size. Immunofluorescence staining and reverse real-time quantitative poly-merase chain reaction(RT-qPCR)were used to examine the expression of glial fibrillary acidic protein(GFAP), AQP-4 and metabotropic glutamate receptor 5(mGluR5). Results Astrocytes in serum free medium showed extensive process bearing morphology,small body and nucleus,and high refractivity.In contrast,in two kinds of 10% FBS-containing medium,astrocytes were flat with large body and nucleus,weak refractivity,as well as short process.Analysis of immunofluorescence staining and RT-qPCR revealed a down-regulation of GFAP and AQP-4 protein and mRNA expression in two kinds of 10% FBS-con-taining medium, compared with that in serum free medium (P<0.001), however, there was no difference in mGluR5 protein and mRNA expression(P>0.05). Conclusion FBS changed astrocyte morphology and down-regulated the expression of GFAP and AQP-4.
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BACKGROUND: Metabotropic glutamate receptors (mGluRs) participate in the induction of synaptic plasticity phenomena, such as long-term potentiation and long-term depression that are thought to be at the origin of learning and memory. They are also likely to play a role in modulating glutamate-induced neurotoxicity. It will become apparent that mGluRs are excellent targets for the development of drugs that modulate excitatory synaptic transmission. But there were several controversies about the exact role of group 1 mGluRs subtype 5 (mGluR5). This study was designed for evaluation of the neuroprotective role of mGluR5. METHODS: Fifty male Sprague-Dawley rats were divided into three groups, control, MK-801 and lamotrigine. The hippocampus and basal ganglia were removed at 6 hours and 3 days after the one hour transient middle cerebral artery occlusion. The gene expression of mRNA of the brain samples were evaluated by using reverse transcriptase polymerase chain reaction technique. RESULTS: The gene expression of mGluR5 mRNA in hippocampus was increased by 101.96 +/- 18.45% at 6 hours after ischemia and decreased by 50.70 +/- 15.73% at 3 days after ischemia (p<0.01). MK-801 and lamotrigine attenuated the ischemia-induced increases of gene expression of mGluR5 mRNA. In MK-801 group, the expression in basal ganglia was increased by only 0.23 +/- 5.41% at 6 hours after ischemia and decreased by 9.82 +/- 4.35% at 3 days after ischemia. In MK-801 group, the expression in hippocampus was decreased by 3.45 +/- 8.24% and 9.35 5.69% at 6 hours and 3 days after ischemia. In lamotrigine group, the expressions in hippocampus and basal ganglia were decreased by 26.66 +/- 9.85% and 9.45 +/- 5.22% at 6 hours after ischemia. CONCLUSIONS: From these results, the role of mGluR5 was defined as a mediator for neuronal damage after transient focal cerebral ischemia in hippocampus and basal ganglia.