High Glucose Induces UCP2 Expression And Activates Mitochondria-Mediated Cell Death Pathway In Astrocytes Exposed To Hypoxia

Objective: Research the expression of UCP2 and mitochondrial apoptosis related factors on astrocytes undergoing OGD/R with hyperglycemia.To observe the role of astrocytes and the molecular in the cerebral ischemia reperfusion with hyperglycemia.Methods: The experiments were performed with those passaged astrocytes. Astrocytes are divided into the following groups:(1)The control group: those astrocytes were cultured with normal conditions(the concentration of glucose was 17.5mmol/l, 37? and 5% CO2 incubator);(2)OGD/R with normal glucose group(OGD6h and then reoxygenation 0?6?12?24h);(3)OGD/R with hyperglycemia group(the concentration of glucose was 50mmol/l; OGD6 h and then reoxygenation 0?6?12?24h). At each time point, we tested the activity of astroeytes with the method of CCK-8. The generation of ROS is detected after DHE staining. The apoptosis rate is detected with AnnexinV-FITC/PI(Floweytometry). The UCP2 and mitochondrial apoptosis related factors(Apaf-1?Caspase-3?Caspase-9) are measured by immunofluorescence?western-blotting and QRT-PCR.Results:(1)CCK-8 and trypan blue staining results showed that with the extension of reoxygenation time, astrocytes survival rate is on the decline, and increased mortality.(2)Flow cytometry detection results suggest the apoptosis rate of astrocytes increases gradually with the extension of reoxygenation time at the normal glucose group. Hyperglycemia group, the apoptosis rate of astrocytes at each time point of OGD/R is significantly higher than normal glucose group, and there is statistical significance.(3)After ROS-specific labeled probe DHE marking, we find there is a significant increase in the group of OGD/R contrast to control group. Hyperglycemia group corresponding to each subgroup, the generation of green fluorescence is stronger than normal glucose group.(4)Compared with normal glucose group, the expression of UCP2 and mitochondrial apoptosis related factors(Apaf-1?Caspase-3?Caspase-9) increased significantly at hyperglycemia group(P<0.05).Conculusions: Oxygen glucose deprivation(OGD) can inhibit the activity of astrocytes. High glucose can increase the apoptosis rate of astrocytes and the generation of ROS after OGD/R.High glucose induces UCP2 expression and aggravates hypoxia injury on astrocytes mediated by the mitochondrial apoptotic pathways.