Harik N, Harik S I, Kuo N T, Sakai K, Przybylski R J, LaManna J C
Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
Brain Res. 1996 Oct 21;737(1-2):335-8. doi: 10.1016/0006-8993(96)00965-1.
The adult rat adapts to prolonged moderate hypobaric hypoxia by polycythemia, increased brain vascularity, and increased density of the brain capillary glucose transporter (GLUT-1). We now report on the time-course and reversibility of these adaptive alterations. Adult male Wistar rats were subjected to hypobaric hypoxia at 0.5 atmosphere for periods of 4 days or 1, 2 or 3 weeks, and compared to normoxic littermate controls. Reversibility of the effects of hypoxia was studied in rats subjected to hypobaric hypoxia for 3 weeks and then allowed to recover at normobaric conditions for 3 additional weeks. Cerebral vascularity was studied in cross-sections of the cerebral cortex that were immunocytochemically stained with a GLUT-1 antibody. The density of GLUT-1 was determined in isolated cerebral microvessels by quantitative autoradiography of immunoblots. Blood hematocrit and cerebral microvascularity did not significantly increase after 4 days of hypoxia, but were significantly increased at 1, 2 and 3 weeks of hypoxia. Three weeks of normoxic recovery after 3 weeks of hypoxia reversed the polycythemia and cerebral hypervascularity. However, the density of GLUT-1 in isolated cerebral microvessels, which was significantly increased after 1 and 3 weeks of hypoxia, remained elevated after 3 weeks of normoxia.
成年大鼠通过红细胞增多、脑血管生成增加以及脑毛细血管葡萄糖转运蛋白（GLUT-1）密度增加来适应长期的中度低压缺氧。我们现在报告这些适应性改变的时间进程和可逆性。成年雄性Wistar大鼠在0.5个大气压下进行低压缺氧处理，持续4天或1、2或3周，并与常氧同窝对照进行比较。在接受3周低压缺氧处理然后在常压条件下再恢复3周的大鼠中研究缺氧影响的可逆性。通过用GLUT-1抗体进行免疫细胞化学染色的大脑皮质横断面研究脑血管生成。通过免疫印迹的定量放射自显影法测定分离的脑微血管中GLUT-1的密度。缺氧4天后，血细胞比容和脑微血管生成没有显著增加，但在缺氧1、2和3周时显著增加。缺氧3周后进行3周的常氧恢复可逆转红细胞增多症和脑血运过多。然而，在缺氧1周和3周后显著增加的分离脑微血管中GLUT-1的密度，在常氧3周后仍保持升高。
