| ã€Objective】Glutamate is the predominant excitatory neurotransmitter throughout the vertebrate central nervous system, including the retina, but can be toxic to retinal ganglion cells (RGCs) at hight concentrations, the accumulation of synaptically released glutamate is mainly prevented by a powerful glial uptake system Glial cells, mainly Müller glia in retina, which express the glutamine synthetase, glutamine synthetase confers upon glial cells an almost unlimited capacity to remove extracellular glutamate. Malfunction of glutamate transport and GS will leads high concentrations of glutamate in the extracellular space. This study was conducted to observe the change of Glutamine synthetase (GS) mRNA and GS activity in the retina. Of the rat model of Diabetes. which allows an early examination of the change in the retina function of diabetic ratsã€Materials and methods】40 male prague-dawley (SD) rats (180—200g) were used for the experiments. They are randomly divided into normal group,diabetic mellitus (DM) group, and diaetes was induced in diabetic mellitus group with streptozotocin(STZ 57mg/kg body weight). The rats were killed separately after 1,2 months, Total RNA was prepared from the 10 rats retinas of each group and the reverse transcriptase-polymerase chain reaction (RT-PCR) analysis were used to detect the glutamine synthetase(GS) expression. The glutamine synthetase activity of 10 rats in each group were evaluated with spectrophotometric assay.ã€Result】The level of glutamine synthetase mRNA in the diabetic mellitus group decreased compared with those in the control (P＜0.05). The activity of the glutamine synthetase in the diabetic rats decreased compared with those in control (P＜0.05).ã€Conclusion】The depression of GS mRNA and the activity of GS occur in the diabetic rats retina which can impair the glutamate metabolism in the retina. And this change might be involved in the pathogenesis of incipient diabetic retinopathy. |
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