Department of Anatomy and Cell Biology, 9312 Scott Hall, School of Medicine, Wayne State University, 540 East Canfield, Detroit, MI 48201, USA.
Neuroscience. 2010 Jul 14;168(3):820-30. doi: 10.1016/j.neuroscience.2010.01.018. Epub 2010 Feb 6.
Endothelin-1 exerts potent vasoconstrictor and vasodilatory effects through its actions on its receptors A (ETrA) and B (ETrB), respectively. While ETrA and B have classically been thought to be expressed on vascular cell types, more recent evidence suggests that, particularly following brain injury, their expression may be seen in other, non-vascular cell types. To date no studies have comprehensively studied the cellular location of endothelin receptors following traumatic brain injury (TBI). Therefore, this study investigates the cellular localization of ETrA and B in normal and traumatized brains using an impact acceleration device. Adult male Sprague-Dawley rats were subjected to TBI by weight drop (450 g) from either 1.5, a distance known to elicit mild TBI in the absence of changed in cerebral blood flow (CBF) or 2 m, a distance shown to cause a significant reduction in CBF. One set of impacted brains were processed for Western determination of ETrA and B expression. Another set were processed for immunofluorescence (IF). For IF, ETrA and ETrB antibodies were combined with cell markers for neurons, astrocytes, microglia, oligodendrocytes, smooth muscle cells and endothelial cells of blood vessels. While ETrA and B was upregulated after more moderate to severe injury (2 m) overall receptor expression was unchanged in response to mild trauma (1.5 m). Double labeling IF confirmed prominent ETrA and ETrB labeling in NeuN labeled pyramidal neurons and interneurons in sensorymotor cortex (smCx) and hippocampus (hipp) post TBI. ETrA rather than ETrB was preferentially co-localized in vascular smooth muscle cells. After injury, a subpopulation of astrocytes in white matter co-localized ETrA but not ETrB. Localization of either receptor in endothelial cells was sparse. No prominent IF was detected in microglia and oligodendrocytes. Taken together with previous findings in other pathological states that show an apparent shift in the localization of ETrA and B, the observed receptor shifts in this work may underlie the ET-1-mediated pathotrajectory of TBI including hypoperfusion.
内皮素-1 通过其对受体 A（ETrA）和 B（ETrB）的作用发挥强大的血管收缩和舒张作用。虽然 ETrA 和 B 经典地被认为表达在血管细胞类型上，但最近的证据表明，特别是在脑损伤后，它们的表达可能在其他非血管细胞类型中可见。迄今为止，尚无研究全面研究创伤性脑损伤（TBI）后内皮素受体的细胞位置。因此，本研究使用冲击加速装置研究了正常和创伤性大脑中 ETrA 和 B 的细胞定位。成年雄性 Sprague-Dawley 大鼠通过从 1.5 米高处（已知在不改变脑血流（CBF）的情况下引起轻度 TBI）或 2 米高处（已知导致 CBF 显著降低）的重量下降（450 克）导致 TBI。一组受影响的大脑用于 Western 测定 ETrA 和 B 的表达。另一组用于免疫荧光（IF）。对于 IF，将 ETrA 和 ETrB 抗体与神经元、星形胶质细胞、小胶质细胞、少突胶质细胞、平滑肌细胞和血管内皮细胞的细胞标志物结合使用。虽然 ETrA 和 B 在更中度至重度损伤（2 m）后上调，但整体受体表达在轻度创伤（1.5 m）后没有变化。双重标记 IF 证实 TBI 后，感觉运动皮层（smCx）和海马（hipp）中的 NeuN 标记的锥体神经元和中间神经元中存在明显的 ETrA 和 ETrB 标记。ETrA 而不是 ETrB 优先与血管平滑肌细胞共定位。损伤后，白质中的一部分星形胶质细胞共定位 ETrA 但不共定位 ETrB。内皮细胞中任何受体的定位都很少。在小胶质细胞和少突胶质细胞中未检测到明显的 IF。与其他病理状态下先前的发现相结合，这些发现表明 ETrA 和 B 的定位明显转移，本工作中观察到的受体转移可能是内皮素-1 介导的 TBI 包括低灌注的 ET-1 介导的病理轨迹的基础。
