Kopolovic J, Brezis M, Spokes K, Rosen S
Department of Pathology, Edith Wolfson Hospital, Holon, Israel.
Virchows Arch A Pathol Anat Histopathol. 1989;414(5):429-37. doi: 10.1007/BF00718627.
Polyethylene glycol protects against O2 deprivation after clamping of the renal artery or norepinephrine infusion and in hypoxic primary cell culture. Isolated perfused kidneys under hypoxic conditions develop morphological alterations in all segments of the proximal tubule and medullary thick ascending limb. In an attempt to ameliorate the effect of hypoxia, rat kidneys were perfused for 90 min with regularly oxygenated (95% O2 + 5% CO2) or hypoxic perfusate (95% N2 + CO2) supplemented with 8-12% polyethylene glycol (MW approximately 8000). In oxygenated and hypoxic kidneys, polyethylene glycol produced similar changes in S1-S2 segments consisting of reduction of cell thickness and organelle compaction with internalization of brush border into the tubulo-vesicular system. In the S3 segment, the cellular volume loss was more limited; the brush border was transformed to membranous whorls and the cytoplasm contained large, irregular, clear zones. Mitochondrial swelling was pronounced in the hypoxic proximal tubules. Polyethylene glycol quantitatively increased and emphasized the damage in the medullary thick ascending limb. Inclusion of 10(-2) M ouabain preserved the medullary thick ascending limb from hypoxic injury and polyethylene glycol had no effect on this undamaged epithelium. Thus, polyethylene glycol affects renal tubules on the basis of their known water permeability and does not protect against but rather worsens hypoxic injury in the medullary thick ascending limb.
聚乙二醇可防止肾动脉夹闭或去甲肾上腺素输注后以及在缺氧原代细胞培养中的氧剥夺。在缺氧条件下，离体灌注的肾脏在近端小管和髓质厚升支的所有节段都会出现形态学改变。为了减轻缺氧的影响，用补充有8-12%聚乙二醇（分子量约8000）的正常氧合（95% O2 + 5% CO2）或缺氧灌注液（95% N2 + CO2）对大鼠肾脏进行90分钟灌注。在氧合和缺氧的肾脏中，聚乙二醇在S1-S2节段产生了类似的变化，包括细胞厚度减少、细胞器压实以及刷状缘内化到微管泡系统中。在S3节段，细胞体积损失更为有限；刷状缘转变为膜性涡旋，细胞质中含有大的、不规则的透明区。缺氧近端小管中线粒体肿胀明显。聚乙二醇在数量上增加并加重了髓质厚升支的损伤。加入10(-2) M哇巴因可保护髓质厚升支免受缺氧损伤，而聚乙二醇对这种未受损的上皮细胞没有影响。因此，聚乙二醇根据肾小管已知的水通透性对其产生影响，并且不能防止而是会加重髓质厚升支的缺氧损伤。
