Hypoxia and an angiogenic response in the partially obstructed rat bladder
Hypoxia and an angiogenic response in the partially obstructed rat bladder
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DOI：
10.1097/01.lab.0000021135.87203.92
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发表时间：
2002-07-01
影响因子：
5
通讯作者：
Levin, RM
中科院分区：
文献类型：
--
作者：
Ghafar, MA;Anastasiadis, AG;Levin, RM
先前对部分膀胱出口梗阻（PBOO）动物模型进行的分子和血流研究使我们提出膀胱缺氧/缺血是由于这种情况而在膀胱中发生的细胞和功能变化的显著效应物。为了证实在部分梗阻的膀胱中缺氧的发生，我们在PBOO后以增加的间隔获得大鼠膀胱，并测量缺氧的生物标志物（hypoxyprobe-1加合物的细胞内形成和缺氧诱导因子-1 α [HIF-1 α]蛋白的表达）以及这种缺氧是否可能引起组织中的血管生成反应。接受PBOO或对照组的大鼠在手术后以增加的间隔用hypoxyprobe-1处理，并将其膀胱切片，并使用检测hypoxyprobe-1加合物的抗体进行免疫染色。对照组大鼠膀胱未染色，而强烈的，但区域限制，hypoxyprobe-1免疫染色中检测到所有阻塞膀胱在一个独特的模式，随着时间的推移而改变。从类似处理的大鼠膀胱中提取蛋白质，并使用Western印迹技术分析HIF-1 α蛋白的表达以及血管生成调节因子（血管内皮生长因子、血管生成素-1和内皮抑素）的表达。HIF-1 α蛋白在对照膀胱中不表达，然而，该蛋白在PBOO后2周内高度上调。同样，血管内皮生长因子（HIF-1 α作用的下游靶点）和血管生成素-1的表达也在梗阻性膀胱中上调，证实了对缺氧的血管生成反应。然而，令人费解的是，抗血管生成分子内皮抑素的表达也被慢性PBOO上调。这些结果进一步支持缺氧参与细胞重塑以及PBOO后膀胱表现出的进行性功能障碍的概念。
Previous molecular and blood flow studies performed on animal models of partial bladder outlet obstruction (PBOO) caused us to propose that bladder hypoxia/ischemia was a significant effector of the cellular and functional changes that occur in the bladder as a result of this condition. To confirm the occurrence of hypoxia in the partially obstructed bladder, we obtained rat bladders at increasing intervals following PBOO and measured biomarkers of hypoxia (intracellular formation of hypoxyprobe-1 adducts and expression of hypoxia inducible factor-1alpha [HIF-1alpha] protein) and whether such hypoxia might elicit an angiogenic response in the tissue. Rats receiving PBOO or controls were treated with hypoxyprobe-1 at increasing intervals subsequent to surgery and their bladders were sectioned and immunostained using an antibody that detects hypoxyprobe-1 adducts. Control rat bladders were unstained, whereas intense, but regionally restricted, hypoxyprobe-1 immunostaining was detected in all obstructed bladders in a unique pattern that changed over time. Proteins were extracted from bladders removed from similarly treated rats and were analyzed for the expression of the HIF-1alpha protein as well as for expression of angiogenic regulatory factors (vascular endothelial growth factor, angiopoietin-1, and endostatin) using Western blotting techniques. HIF-1alpha protein was not expressed in control bladders, however, the protein was highly up-regulated over the 2-week period after PBOO. Likewise, the expression of vascular endothelial growth factor (a downstream target of HIF-1alpha action) and angiopoietin-1 was also up-regulated in obstructed bladders confirming an angiogenic response to this hypoxia. Enigmatically, however, expression of the antiangiogenic molecule endostatin was also up-regulated by chronic PBOO. These results further support the concept that hypoxia is involved in the cellular remodeling as well as in the progressive functional impairment exhibited by the urinary bladder after PBOO.