The Expression Of IRP2mRNA,FnmRNA,TfRmRNA In Rat Brain With Iron Deficiency Anemia

Background and ObjectionIron is an essential factor in many important cell functions, including grow th, immunological response and energy production. It is important to maintain cellular iron homeostasis for cell proliferation and normal function. The iron re gulatory proteins (IRPs ) and the ferritin (Fn) and the transferrin receptor (TfR) involved in the maintenance of cellular iron homeostasis. Fn and TfR are use d by cells to adjust intracellular iron concentration to levels in order to be ade quate for their metabolic needs. IRPs might bind to transcripts of ferritin, trans ferrin receptor to control the expression of iron metabolism proteins at the post-transcriptional level.Brain iron plays essential roles in growth, myelogenesis, neurotransmitter metabolism and other features of brain function. So, iron metabolism is very important to brain cells. However, how it works in brain cells, there aren't some clear answers.In our study, we established the animal model of rats with nutritional iron deficiency and detected the expression of IRP2mRNA, FnmRNA, TfRmRNA in four different brain regions (white matter,cortex, hippocampus and striatum)of the model in order to probe their roles in these regions . Method:Select forty healthy adult Wistar rats, and randomly divided them into con -trol group and iron deficiency group. The model of rat with nutritional iron deficiency anemia(IDA) was established by the Liao Qing Kui . From fifteen to sixty days, iron deficiency and IDA gradually occurs in the rats. We collect ed 1.5 milliliter bloods from orbital vein plexus of each rat and obtained the serum samplesto detect the serum iron (SI), serum ferritin (SFn). According to the concentration of SI, SFn and the rats were divided into four groups: control group(CN),the group of recessive iron deficiency(RC), the group of mild iron deficiency anemia(ML), the group of moderate iron deficiency anemia (MD). The samples of the brain regions of rat were dissected .All sections were frozen at -70℃ in sealed containers until they were homogenized. By the instruction of the Test Kit, the total RNA of the sample was extract ed, and then preserved in liquid nitrogen. Freezingly .The expression of IRP2 mRNA , Fn mRNA and TfR mRNA of samples were detected by the RT-PC R . sFn was measured by Che-miluminescence Assay and SI was measured by flame Assay ,etc. Result①IRP2mRNA: The expression levels of IRP2mRNA in four different brain regions (white matter,cortex, hippocampus and striatum),respectively, remained constant among CN, RC, ML and MD groups. There were not statistically diff erence among them (P > 0.05).②TfR mRNA: The expression levels of TfRmRNA was increased as iron defi ciency increased. In four different brain regions, there were statistically differen ce between ML or MD with CN or RC groups(P<0.05). ③FnmRNA: The expression of FnmRNA was decreased as the increasing of iron deficiency in white matter, hippocampus or striatum. And there were statis tically difference between ML or MD with CN or RC groups(P<0.05). Howeve r, the expression of FnmRNA had no change in cortex, and there was not statistically difference among CN, RC, ML and MD groups(P>0.05). conclusion:1. The total expression levels of IRP2 mRNA remained constant in rat's brain with ID/IDA. This result suggests that the amount of IRP2 maybe change by the procession of iron dependent - ubiquitin - proteasome system.2. The expression of TfRmRNA was increased when iron deficiency increased. This result showed that TfR play a role in brain iron metabolism.3. The expression of FnmRNA was decreased with the increased of iron deficiency in more different brain regions. That indicated that Fn also play a role i n brain iron metabolism.4. The expression of FnmRNA wasn't decreased with the increased of iron def iciency in cortex. Maybe this indicate that there should be another regulation mechanism in rat brain? .5. The different cells in brain have different requirement for iron. So, there iron metabolism could have themselves characteristic.