Chen W, Hunt D M, Lu H, Hunt R C
Department of Microbiology and Immunology, University of South Carolina School of Medicine, Columbia 29208, USA.
Invest Ophthalmol Vis Sci. 1999 Mar;40(3):744-51.
In retinopathy of prematurity, capillary growth in the retina is attenuated. Subsequent cyclic elevation of oxygen levels leads to renewed capillary growth that may eventually result in retinal detachment. It is hypothesized that the sensitivity of the premature retina to oxidative shock results from the absence of antioxidant protective proteins.
The expression of heme oxygenase-1, metallothionein, superoxide dismutase, and catalase mRNAs was measured in retinas of rats from 6 days before birth to 4 days after birth using in situ hybridization and semiquantitative reverse transcription-polymerase chain reaction with Southern blot analysis.
Superoxide dismutase mRNA was expressed to a similar extent at all time points. Metallothionein mRNA expression, which was high at embryonic days (E) 16 and 18, decreased to low levels by the time of birth and remained low at least until 4 days after birth. Catalase mRNA expression was low until birth and increased until at least postnatal day 4. Heme oxygenase-1 mRNA showed low expression at E16 and E18, increased before birth, and then diminished.
Four antioxidant protein mRNAs showed very different patterns of expression in the rat retina. Two of these proteins, heme oxygenase-1 and catalase, were expressed at relatively low levels until approximately the time of birth. The former is important in protection against heme-mediated generation of reactive oxygen species, whereas the latter protects against hydrogen peroxide-generated damage. As a result of the low expression of these mRNAs, and presumably the proteins encoded by them, the premature rat (and probably the premature human) is likely to be born without a full complement of antioxidant defenses.
在早产儿视网膜病变中，视网膜中的毛细血管生长减弱。随后氧水平的周期性升高会导致毛细血管重新生长，最终可能导致视网膜脱离。据推测，早产儿视网膜对氧化应激的敏感性源于缺乏抗氧化保护蛋白。
使用原位杂交以及半定量逆转录-聚合酶链反应和Southern印迹分析，测定出生前6天至出生后4天大鼠视网膜中血红素加氧酶-1、金属硫蛋白、超氧化物歧化酶和过氧化氢酶mRNA的表达。
超氧化物歧化酶mRNA在所有时间点的表达程度相似。金属硫蛋白mRNA在胚胎期（E）16和18时表达较高，到出生时降至低水平，并且至少在出生后4天一直保持低水平。过氧化氢酶mRNA在出生前表达较低，并且至少在出生后第4天之前持续增加。血红素加氧酶-1 mRNA在E16和E18时表达较低，在出生前增加，然后减少。
四种抗氧化蛋白mRNA在大鼠视网膜中呈现出非常不同的表达模式。其中两种蛋白，即血红素加氧酶-1和过氧化氢酶，在大约出生时之前表达水平相对较低。前者在防止血红素介导的活性氧生成方面很重要，而后者则防止过氧化氢造成的损伤。由于这些mRNA以及可能由它们编码的蛋白质表达水平较低，早产大鼠（可能还有早产人类）出生时可能没有完整的抗氧化防御机制。
