p47phox介导早产儿氧暴露后体内活性氧簇产生的机制

Mechanism for p47phox - induced reactive oxygen species increasing after oxygen therapy in premature infants

目的探讨早产儿氧暴露后，患儿外周血单个核细胞（PBMCs）内烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶亚单位p47phox调节细胞内活性氧（ROS）升高的机制。方法胎龄〈32周需吸氧早产儿根据吸入氧体积分数（FiO2）不同分为3组：FiO2〈30％为低氧组、FiO2在30％-40％为中氧组、FiO2〉40％为高氧组。同期未吸氧的〈32周早产儿为对照组。氧疗48h后，各组经桡动脉采血3mL，分离PBMCs及血清，应用激光共聚焦显微镜检测PBMCs内ROS生成量，硫代巴比妥酸比色法检测血清丙二醛（MDA）水平，免疫荧光检测p47phox在细胞内定位及p47phox的活化率。结果早产儿氧暴露后，随着Fi02的升高，ROS与MDA逐渐升高，p47phox由胞质向胞膜移位的细胞数增多，p47phox的移位率也在增加；与刘照组相比，余3组ROS明显升高，差异有统计学意义（q=4．48、6．5、16．22，P均〈0．05）；MDA水平显著增加，差异有统计学意义（q=5．08、8．22、12．76，P均〈0．05）；p47phox的活化率比较差异也具有显著性差异（χ^2=134．008，P〈0．05）；与中氧组相比，高氧组ROS和MDA显著升高，差异有统计学意义（q=15．03、4．53，P均〈0．05）；p47phox的活化率明显增加，差异有统计学意义（χ^2=19．26，P〈0．05）。结论早产儿氧暴露后，p47phox可能通过向胞膜移位来调节PBMCs内NADPH氧化酶源性活性氧升高。

Objective To explore the mechanism for the increase in reactive oxygen species regulated by p47phox of nicotinamide adenine dinucleotide phosphate（NADPH） oxidase subunit in peripheral blood mononuclear cells （PBMCs） after oxygen therapy in premature infants. Methods According to different volume fractions of oxygen, premature infants less than 32 weeks were divided into 3 groups：fractional concentration of inspired oxygen （FiO2 ） 〈 30% was low concentration oxygen group,FiO2 between 30% and 40% as middle concentration oxygen group, and FiO2 〉 40% as high concentration oxygen group. Premature infants less than 32 weeks without oxygen was control group. After 48 h,3 mL blood was collected via radial artery from each group,PBMCs and serum were separated. Then intracellular reactive oxygen species （ROS） by confocal laser scanning microscopy, malondialdehyde （MDA） within serum by thiobarbituric acid colorimetric, and the location and activation rate of p47phox through immunofluorescence. Results After premature infants were exposed to oxygen, as the oxygen volume fraction was increasing, ROS and MDA gradually rise＆ More PBMCs with p47phox translocated to membrane, then the translocation rate of p47phox also increased. Com- pared with the control group, ROS were significantly higher（ q = 4.48,6.5,16.22, all P 〈 0.05 ） among the other 3 groups ; MDA significantly increased as well（ q = 5.08,8.22,12.76, all P 〈 0.05 ） ; the activation rate of p47phox also had significant differences （χ^2 = 134. 008, P 〈 0.05 ）;compared with the middle concentration oxygen group, the high concentration oxygen group had higher ROS and MDA（ q = 15.03,4.53, all P 〈 0.05 ） ;the activation rate of p47phox increased sigmficantly （χ^2 = 19.26, P 〈 0.05 ）. Conclusions After oxygen exposure, p47phox translocated to mem- brane may regulate the NADPH oxidase- derived ROS increase in extremely premature infants.