紫绀先心病患儿血清铁及心肌中铁和转铁蛋白受体-1变化及意义的研究

发布时间：2018-03-16 23:34

本文选题：紫绀型先心病　切入点：慢性缺氧　出处：《第三军医大学》2012年博士论文　论文类型：学位论文

【摘要】：背景：紫绀先天性心脏病是由心内右向左分流引起的，可造成患者慢性缺氧及紫绀，临床新生儿的发病率及死亡率很高。患者机体可通过增加血红蛋白、肌红蛋白、细胞内线粒体的数量及加强糖酵解等多种代偿方式，以增加氧气的释放，并减低能量的消耗，重塑细胞的能量供求平衡，使心肌细胞能够最大限度的适应缺氧环境，维持细胞基本的生存和功能。铁是肌红蛋白、细胞色素及线粒体电子传递链中辅基的重要组成成分，是机体不可缺少的重要元素，主要参与心肌细胞对氧气的转运和利用。在低氧环境中，有很多参与铁稳态的基因表达发生变化，其中很多基因为低氧诱导因子HIFs(Hypoxia-inducible factors HIFs)的直接靶点。HIFs可直接作用于目的基因的低氧反应原件(hypoxia-responsive elements HRE)，以增强其表达。转铁蛋白受体-1(Transferrin Receptor-1TfR-1)为心肌细胞摄取铁的主要蛋白之一。有学者研究发现，在TfR-1基因的启动子上存在一个HRE。但TfR-1在心肌慢性缺氧与铁代谢间存在着怎样的作用仍不明确，我们提出假设：在慢性缺氧环境下，心肌细胞可能通过调节TfR-1的表达从而改变心肌铁代谢，以实现心肌慢性缺氧适应。本研究将通过观察紫绀先心病患儿血清铁及总铁结合力、心肌中非血红素铁的含量以及TfR-1的表达情况，明确是否在紫绀先心病患儿外周血及心肌组织中伴随铁代谢的改变，进而探讨心肌组织内铁含量及TfR-1对心肌组织慢性缺氧适应的意义。研究方法：本研究经新桥医院伦理委员会批准，共分三个分题：分题一：选取紫绀先心病患儿23例，非紫绀先心病患儿24例。以静脉血为标本，检测患儿血红蛋白含量、红细胞压积，以亚铁嗪法检测血清铁及总铁结合力，以了解紫绀先心病患儿机体铁储备的改变。分题二：选取紫绀先心病患儿20例，非紫绀先心病患儿15例。以术中右室流出道心肌组织为标本，使用亚铁嗪法检测心肌组织中非血红素铁含量，并用Perls-DAB法检测心肌组织中铁的分布，以了解紫绀先心病患儿心肌组织摄取铁的变化。分题三：以分题二中入组病例右室流出道心肌为标本，采用Western blot法检测心肌组织中TfR-1蛋白的表达量，免疫组化法检测心肌组织中TfR-1的分布和定位，以了解TfR-1蛋白在紫绀先心病患儿心肌组织中的表达变化。研究结果：主要结果如下： 1.两组患儿血红蛋白含量及红细胞压积都基本处于正常范围内，但组间差异较大。与非紫绀组相比，紫绀组先心病患儿血红蛋白含量明显升高(166.7g/L±22.1g/L比125.6g/L±11.9g/L, p0.05)，紫绀先心病患儿平均红细胞压积也明显高于非紫绀组(52.4%±8.8%比37.7%±3.1%，p0.05)。 2.亚铁嗪法检测患儿血清铁及总铁结合力，与非紫绀先心病患儿相比，紫绀组患儿血清铁明显下降(23.25μmol/L±4.4μmol/L比31.34μmol/L±4.2μmol/L, p0.05)，总铁结合力增加(69.59μmol/L±5.8μmol/L比52.67μmol/L±9.2μmol/L, p0.05),与非紫绀先心病患儿组差异显著。 3.亚铁嗪法检测患儿心肌非血红素铁含量，与非紫绀组患儿相比，紫绀组患儿心肌非血红素铁明显升高，相比有显著差异(6.12μmol/g±0.67μmol/g比4.02μmol/g±0.68μmol/g，p0.05)。Perls-DAB法检测心肌中铁的分布，非紫绀组患儿心肌可见少量阳性颗粒，紫绀组患儿心肌可见大小不等的阳性颗粒明显增多。 4.Western blot检测结果显示：与非紫绀组患儿相比，紫绀组患儿心肌中TfR-1蛋白表达明显增强，其相对光密度比值(OD)明显强于非紫绀组(0.62±0.02比0.39±0.02，p0.001)。免疫组化结果显示：在紫绀组患儿心肌胞浆中及胞膜上TfR-1蛋白广泛表达，较非紫绀组明显增加。结论： 1.在紫绀先心病患儿体内，外周血血红蛋白及红细胞压积的升高，伴随血清铁下降以及总铁结合力的增加。提示在慢性缺氧的情况下，患儿机体处于一种潜在的铁缺乏状态，大量的铁可能被机体组织摄取，用于适应这重慢性低氧环境，如合成血红蛋白及红细胞数量以增加血液的携氧能力，造成机体铁储备下降。 2.紫绀先心病患儿心肌组织中铁颗粒明显增多，，并且伴随非血红素铁浓度也明显升高，表明除血红蛋白的合成需要更多的铁，心肌组织内相应含铁蛋白合成的增强，也需要心肌组织摄取大量的铁，这一改变可能为心肌慢性缺氧适应中的关键环节。 3.紫绀先心病患儿心肌组织中TfR-1的表达明显高于非紫绀组。提示在慢性缺氧环境中，TfR-1作为心肌组织中摄取铁的主要分子，其表达增强有助于心肌细胞摄取更多的铁，协助心肌细胞完成低氧适应机制。
[Abstract]:Background:
Cyanotic congenital heart disease is caused by intracardiac right to left shunt, can cause patients with chronic hypoxia and cyanosis, morbidity and mortality in neonates is high. Patients can increase hemoglobin, myoglobin, the number of mitochondria in cells and enhance glycolysis and other compensatory way to increase oxygen release, and to reduce energy consumption, energy supply and demand balance remodeling cells, myocardial cells can adapt to hypoxic environment, to maintain the survival and function of cells.
Iron is myoglobin, cytochrome and an important component of mitochondrial electron transfer cofactor in the chain, is an important element of the indispensable, mainly involved in the myocardial cells of oxygen transport and utilization. In hypoxia environment, there are many expression of genes involved in iron homeostasis changes, many of them because of hypoxia inducible factor HIFs (Hypoxia-inducible factors HIFs) hypoxia response of the original direct targets of.HIFs can be directly applied to the target gene (hypoxia-responsive elements HRE), to improve the expression of transferrin receptor. -1 (Transferrin Receptor-1TfR-1) is one of the main protein in myocardial uptake of iron. Some scholars have found that in the promoter of TfR-1 gene, but the existence of a HRE. TfR-1 in the myocardium of chronic hypoxia and iron metabolism exist between what role is not clear, we hypothesized that in chronic hypoxia environment, myocardial cell The myocardial iron metabolism may be altered by regulating the expression of TfR-1 in order to realize the chronic hypoxia adaptation of the myocardium.
This study through the observation of cyanosis congenital heart disease in children with serum iron and TIBC, non heme iron content and the expression of TfR-1 in myocardium, whether in cyanotic congenital heart disease in children with peripheral blood and myocardial tissue with iron metabolism, and then discuss the Fe and TfR-1 in myocardial tissue of myocardial adaptation to chronic the significance of hypoxia.
Research methods:
The study was approved by the Xinqiao Hospital Ethics Committee and divided into three points:
Topic: the cyanosis congenital heart disease in children with 23 cases of non cyanotic congenital heart disease in children. In 24 cases of venous blood were detected with hemoglobin, hematocrit, the FerroZine assay of serum iron and total iron binding capacity, in order to understand the cyanotic congenital heart disease in children body iron reserves change.
Section two: selection of cyanotic children with congenital heart disease in 20 cases, 15 cases of non cyanotic congenital heart disease in children. As of right ventricular outflow tract myocardium were non heme iron content of myocardial tissue were detected using FerroZine method, and the distribution of Perls-DAB was used to detect the myocardial tissue in congenital heart disease, in order to understand the changes of myocardial tissue in purple purple children with iron uptake.
Section three: the topic 2 cases of right ventricular outflow tract myocardium specimens, TfR-1 protein expression in myocardial tissue was detected by Western blot method, the distribution and localization of TfR-1 were detected by immunohistochemistry in myocardial tissue, in order to understand the TfR-1 protein in cyanotic children with congenital heart disease myocardial tissues.
The results of the study:
The main results are as follows:
1. two groups of children with hemoglobin and hematocrit were basically in the normal range, but the differences between the groups. Compared with non cyanotic group, cyanosis group of children with congenital heart disease hemoglobin content increased obviously (166.7g/L + 22.1g/L 125.6g/L + 11.9g/L, P0.05), cyanosis congenital heart disease in children with average hematocrit were significantly higher than those in non cyanosis group (52.4% + 8.8% to 37.7% + 3.1%, P0.05).
2. children with FerroZine method to detect serum iron and TIBC, compared with non cyanotic congenital heart disease in children, serum iron group cyanosis decreased significantly (23.25 mol/L + 4.4 mol/L than 31.34 mol/L + 4.2 mol/L, P0.05), total iron binding capacity increased (69.59 mol/L + 5.8 mol/L 52.67 mol/L + 9.2 mol/L, P0.05), and non cyanotic children with congenital heart disease group were significantly different.
3. children with FerroZine method detection of myocardial non heme iron content, compared with non cyanosis group, cyanosis group with myocardial non heme iron was significantly increased, there was significant difference (6.12 mol/g + 0.67 mol/g than 4.02 mol/g + 0.68 mol/g, P0.05).Perls-DAB method for detection of myocardial iron distribution, non cyanosis group a small amount of myocardial positive granules, positive granules were visible cyanosis myocardial sizes increased significantly.
4.Western blot test results show that: compared with non cyanosis group, significantly enhanced the expression of TfR-1 protein in cardiac muscle in cyanotic group, the relative optical density ratio (OD) was significantly stronger than that of non cyanosis group (0.62 + 0.02 to 0.39 + 0.02, p0.001). Immunohistochemistry results showed that: in the group with myocardial cytoplasm cyanosis and cell membrane TfR-1 protein is widely expressed, compared with non cyanotic group increased significantly.
Conclusion:
In 1. children with congenital heart disease in cyanosis, increased peripheral blood hemoglobin and hematocrit, serum iron decreased with the increase of TIBC. In chronic hypoxia condition, with the body in a potential iron deficiency, large amounts of iron may be the body tissue uptake, to adapt to this heavy chronic hypoxia environment, such as the number of synthesis of hemoglobin and red blood cells to increase blood oxygen carrying capacity, resulting in a decline in body iron reserves.
2. cyanosis congenital heart disease myocardial tissues of children with iron particles increase obviously, and the non heme iron concentration also increased significantly, except for that of hemoglobin synthesis needs more iron, myocardium containing enhanced ferritin synthesis, myocardial tissue uptake also needs a large amount of iron, this change may be the key link of myocardial adaptation to chronic hypoxia.
The expression of TfR-1 3. in cyanotic children with congenital heart disease myocardial tissue were significantly higher than those in non cyanotic group. In chronic hypoxia environment, TfR-1 as the main molecular iron uptake in myocardial tissue, its expression contribute to enhancement of myocardial uptake more iron, myocardial cells adapt to hypoxia assist complete mechanism.

【学位授予单位】：第三军医大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R725.4

【共引文献】