摘要
目的探讨新生儿肺透明膜病(HMD)支气管肺泡灌洗液(BALF)中肺泡巨噬细胞(AM)核转录因子κB(NF-κB)和核转录因子抑制物κB-α(IκB-α)的表达及其在HMD中的发病机制。方法31例HMD机械通气治疗的早产儿,分为存活组22例和死亡组9例,另19例无呼吸系统疾病的早产儿为对照组。收集BALF,分离和培养AM；离体实验用细菌内毒素(LPS)刺激各组AM,提取细胞核蛋白。NF-κB的表达检测采用电泳迁移率实验(EMSA)；应用免疫斑点杂交(Western blot)检测κB-α的表达；用酶连免疫法(ELISA)测定BALF上清液中细胞因子IL-1β和IL-8的含量。结果存活组在上机后24地h和72 h AM中NF-κB表达均明显高于对照组。死亡组在上机后24 h AM中NF-κB表达明显增高,而72 h时减低,并经LPS刺激后无NF-κB表达明显增高。在上机后24和72 h对照组的AM中IκB-a表达高于存活组和死亡组。死亡组在上机后24和72 h,AM中IκB-α表达差异无统计学意义,并经LPS刺激后也无IκB-α的再表达。NF-κB表达与IL-1β和IL-8呈明显正相关。结论NF-κB的过度表达参与了新生儿肺透明膜病的病理生理发病机制,其途径可能降低IκB-α的表达和增加了IκB-α降解或两者都有。
Objective Inflammatory reaction and injury in immature lungs are associated with activation of nuclear factor-kappa B （NF-κB） to trigger proinflammatory cytokine release, but the mechanism thereof is not fully understood. The present study was conducted to understand possible relationship between expression of NF-κB and its inhibitor and severity and outcome of neonates with hyaline membrane disease （HMD）. Methods Serial samples of bronchoalveoar lavage fluid （BALF） were obtained during mechanical ventilation from 31 preterm infants with HMD. These infants were divided into two groups：survivors group [n =22, birth weight （ 1500±320） g and gestational age （31.2 ± 1.8） weeks] and nonsurvivors group [ birth weight （1340 ± 280） g, gestational age （30. 8 ± 2. 1 ） weeks ]. Ninteen preterm infants [ birth weight （ 1470 ± 280） g, gestational age （ 30. 6 ± 1.9） weeks ] without respiratory disorders were enrolled as control subjects. Alveolar macrophages （AM） were isolated by differential adherence. AM was cultured and treated with lipopolysaccharide （LPS） for 1 hr. Then, nuclear extracts of AM were analyzed by electrophoretic mobility shift assay （EMSA） for NF-κB expressiorl. NF-κB inhibitor （ IκB-α protein） in cytoplasmic extracts was detected by using Western blotting and IL-1β and IL-8 in BALF by enzyme-linked immunosorbent assay （ELISA）. Results NF-κB complexes were observed by EMSA, they were characterized by competition with cold oligonucleotide and p65-specific antibodies. The addition of an excess of cold oligonucleotide, corresponding to the NF-κB binding site, turned off the signal of the band, showing that the band was specific. An excess of an irrelevant oligonucleotide （ corresponding to the SP-1 ） did not show any effect. The addition of an anti-p65 antibody caused the supershift of the two upper bands. After EMSA, the NF-κB complexes were quantified by using a ImageQuant software. NF-κB expression in AM at 24 hrs was higher in all the patients with HMD as compared with control subjects （survives/control, 34. 1 vs 11.4 RDU,P 〈0. 01 ; nonsurvivors/control, 55.2 vs 11. 4 RDU,P 〈0. 01 ）. The NF-κB expression in AM at 72 hrs was higher than that in control subjects but not for nonsurvivors （survivors/control,47.8 vs 25. 6 RDU ,P 〈 0.01 ; nonsurvivors/control, 21.8 vs 25. 6, P 〉 0. 05 ）. The NF-κB expression in AM from nonsurvivors was depressed at 72 hrs as compared to 24 hrs （21.8 vs 55. 2 ,P 〈0. 01 ） , whereas the NF-κB expression in AM from survivors was still higher at 72 hrs than that at 24 hrs （47. 8 vs 34. 1 ,t =4. 43 ,P 〈 0. 01 ）. Conclusion Altered NF-κB activation in AM of BALF of neonates with HMD was observed, and it may be mediated by decreased IκB synthesis, increased IκB degradation, or both. In HMD nonsurvivors NF- κB translocation was hampered upon LPS activation.
出处
《中华儿科杂志》
CAS
CSCD
北大核心
2006年第8期602-606,共5页
Chinese Journal of Pediatrics
