Manganese superoxide dismutase expression in alveolar type II epithelial cells from nonventilated and hypoperfused lungs.
Manganese superoxide dismutase expression in alveolar type II epithelial cells from nonventilated and hypoperfused lungs.
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非通气和低灌注肺的肺泡 II 型上皮细胞中锰超氧化物歧化酶的表达。
DOI：
10.1165/ajrcmb.11.3.8086173
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发表时间：
1994
影响因子：
6.4
通讯作者：
Jackson,RM
中科院分区：
文献类型：
--
作者：
Russell,WJ;Matalon,S;Jackson,RM
由于肺不张导致的缺氧和低灌注以及由此导致的肺动脉血流减少导致锰超氧化物歧化酶（MnSOD）活性特异性降低，并且在再氧化过程中对氧化损伤敏感。由于MnSOD蛋白集中在肺泡上皮II型细胞（ATII）的线粒体中，我们假设这些细胞中MnSOD的表达也会因缺氧而降低。为了研究MnSOD的表达调控是发生在转录前还是转录后，我们测定了缺氧后MnSOD蛋白含量或稳态mRNA水平是否也发生了变化。采用弹性酶消化法从右肺缺氧低灌注7天的成年兔肺中分离出ATII细胞。在1 mM KCN存在下，通过抑制细胞色素c的减少来测定MnSOD的活性，在免疫印迹上测定MnSOD蛋白含量，在狭缝印迹自显像上定量MnSOD mRNA。对照肺ATII细胞的MnSOD活性为8.4 +/- 1.9 U/mg蛋白，缺氧和低灌注肺ATII细胞的MnSOD活性为6.8 +/- 1.5 U/mg蛋白（n = 9, P = 0.037）。对照组ATII细胞MnSOD蛋白含量为5.1 +/- 1.4微克/毫克蛋白，缺氧和低灌注肺ATII细胞MnSOD蛋白含量为4.1 +/- 1.2微克/毫克蛋白（P = 0.021）。RNA槽型印迹法测定正常肺ATII细胞MnSOD mRNA/18S核糖体RNA（任意吸光度单位比）为2.18 +/- 1.26，缺氧肺ATII细胞MnSOD mRNA/18S核糖体RNA为2.94 +/- 0.88 （n = 7, P < 0.05）。（摘要删节250字）
Lungs that have been hypoxic and hypoperfused because of atelectasis and the resulting decrease in pulmonary arterial blood flow develop specific decreases in manganese superoxide dismutase (MnSOD) activity and are sensitive to oxidant injury during reoxygenation. Since the MnSOD protein is concentrated in mitochondria of alveolar epithelial type II cells (ATII), we hypothesized that expression of MnSOD would be decreased in these cells also as a result of hypoxia. To investigate whether regulation of MnSOD expression occurred before or after transcription, we determined whether MnSOD protein content or steady-state mRNA level changed after hypoxia as well. ATII cells were isolated by elastase digestion from lungs of adult rabbits after right lungs had been hypoxic and hypoperfused for 7 days because of unilateral atelectasis. MnSOD activity was measured by inhibition of cytochrome c reduction in the presence of 1 mM KCN, MnSOD protein content was measured on immunoblots, and MnSOD mRNA was quantified on slot blot autoradiograms. MnSOD activity was 8.4 +/- 1.9 U/mg protein in ATII cells from control lungs and 6.8 +/- 1.5 U/mg protein in ATII cells from hypoxic and hypoperfused lungs (n = 9, P = 0.037). MnSOD protein content was 5.1 +/- 1.4 micrograms/mg protein in ATII cells from control and 4.1 +/- 1.2 micrograms/mg protein in ATII cells from hypoxic and hypoperfused lungs (P = 0.021). ATII cell MnSOD mRNA/18S ribosomal RNA (ratio of arbitrary absorbance units) determined by RNA slot blots was 2.18 +/- 1.26 in ATII cells from control lungs and 2.94 +/- 0.88 in ATII cells from hypoxic lungs (n = 7, P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)