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目的:探讨脑缺血对大鼠皮层、海马二价金属离子转运体1(DMT1)表达的影响。方法:雄性Wistar大鼠随机分为脑缺血1、3、7、28 d和假手术组。结扎双侧颈总动脉建立脑缺血模型组,假手术组仅分离双侧颈总动脉但不结扎。采用RT-PCR测定DMT1+/-IRE mRNA的表达;采用免疫组化染色测定大鼠皮层及海马组织DMT1的表达。结果:大鼠皮层和海马DMT1+/-IRE mRNA的表达随缺血时间的延长逐渐增加。与假手术组比较,皮层DMT1+/-IRE mRNA的表达在缺血1、3 d时无差异(P>0.05);缺血7 d时表达增加(P<0.01),缺血28d时增加更明显(P<0.01)。海马DMT1-IRE mRNA表达除在缺血1 d时与假手术组无差异外(P>0.05),其余时间点DMT1+/-IRE mRNA表达均高于假手术组(P<0.01)。随缺血时间的延长,大鼠皮层、海马的锥体细胞、颗粒细胞及血管内皮细胞DMT1的表达逐渐增加。DMT1的表达除缺血1 d组与假手术组无差别外(P>0.05),其余各组均高于假手术组(P<0.05)。结论:脑缺血可诱导大鼠皮层及海马DMT1表达升高,DMT1表达的改变可能参与了脑缺血引起大鼠脑铁含量升高及神经元铁沉积过程。
Objective: To investigate the effects of cerebral ischemia on the expression of divalent metal ion transporter 1 (DMT1) in the cortex and hippocampus of rats. Methods: Male Wistar rats were randomly divided into 1, 3, 7 and 28 days after cerebral ischemia and sham operation group. The bilateral common carotid arteries were ligated to establish the model group of cerebral ischemia. The sham-operation group only separated the common carotid artery but not ligation. The expression of DMT1 +/- IRE mRNA was detected by RT-PCR. The expression of DMT1 in rat cortex and hippocampus was detected by immunohistochemistry. Results: The expression of DMT1 +/- IRE mRNA in rat cortex and hippocampus gradually increased with the prolongation of ischemia time. Compared with the sham group, the expression of DMT1 +/- IRE mRNA in the cortex was not significantly different at 1 and 3 days after ischemia (P> 0.05), but increased at 7 days after ischemia (P <0.01) (P <0.01). The expression of DMT1-IRE mRNA in the hippocampus was higher than that in the sham-operated group (P <0.01) except that the expression of DMT1-IRE mRNA was not significantly different from that of the sham operation group on the 1st day of ischemia (P> 0.05). With the extension of ischemia time, the expression of DMT1 in rat cortex, hippocampal pyramidal cells, granulosa cells and vascular endothelial cells gradually increased. DMT1 expression was similar to that of sham-operation group (P <0.05) except ischemia group 1 d and sham operation group (P> 0.05). CONCLUSION: Cerebral ischemia can induce the increased expression of DMT1 in rat cortex and hippocampus. The alteration of DMT1 expression may be involved in the increase of brain iron content and the process of iron deposition in rats.