产前给药地塞米松对大鼠胎肺形态结构及Wnt信号转导途径影响的实验研究
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摘要
目的
产前应用地塞米松(DEX)可以抑制炎症反应、促Ⅱ型肺泡细胞成熟、增加肺表面活性物质合成并促其分泌,减少早产儿呼吸窘迫综合症(RDS)的发生,同时也存在阻碍肺发育的现象。胚胎时期的肺发育受到多条信号途径影响,其中Wnt信号转导途径参与调控肺上皮细胞和间质细胞分化、细胞增殖及凋亡等过程,在肺发育过程中起着重要作用。因此我们采用早产鼠肺模型,比较产前给予不同剂量、不同疗程地塞米松对大鼠胎肺形态发育及Wnt信号转导途径的影响。
方法
20只孕鼠分5种情况用药,胎鼠分5组,每组约16只。小剂量、大剂量DEX单程组:分别于孕16、17天注射等量生理盐水,孕18天腹腔注射DEX 0.4 mg/kg、0.8 mg/kg;小剂量、大剂量DEX多程组:分别于孕16、17、18天腹腔注射DEX 0.4 mg/kg、0.8 mg/kg。注射时DEX均用生理盐水稀释至0.5ml;其中小剂量、大剂量DEX单程组和多程组统称为DEX组。对照组:孕16、17、18天注射等量生理盐水。雌鼠孕19天时破宫后取胎鼠肺组织作为早产鼠肺模型,每只孕鼠随机取4只早产鼠,共16只取全肺分别通过光镜观察及电镜技术,分析比较各组胎肺形态发育的差异、RT-PCR方法检测Wnt信号转导途径中Wnt7b、Wnt5a、Wnt2、GSK-3β和β-catenin基因mRNA的表达,Western-Blot、免疫组化方法检测GSK-3β、β-catenin蛋白表达量和表达部位。
结果
1.HE染色光镜观察结果:DEX组与对照组相比,肺泡数目减少、肺泡腔结构扩大,肺泡间隔厚度变薄、周围结缔组织减少。其中小剂量DEX单程、多程组及大剂量DEX单程、多程组每视野肺泡计数,平均肺泡间隔厚度均低于对照组(P＜0.01),平均肺泡表面积均高于对照组(P＜0.01)。
2.电镜观察结果:DEX组Ⅱ型肺泡上皮细胞内可见板层小体且染色深、致密,胞质内线粒体等细胞器增多;而对照组内难见板层小体、细胞器数目减少。随着DEX用药剂量和次数的增多,板层小体数目逐渐增多,基底膜则呈现由完整到断裂不连续、由厚薄均一到厚薄不均甚至无法辨认的变化,且大剂量DEX组中的线粒体数目较小剂量组少,内质网也有扩张。
3.RT-PCR结果:DEX组胎肺Wnt7b及β-catenin基因mRNA的表达量均显著高于对照组(P＜0.05);GSK-3β表达量较对照组减少(P＜0.05)。小剂量DEX单程、多程组及大剂量DEX单程组Wnt5a基因mRNA表达均低于对照组(P＜0.05),不同剂量DEX多程组之间差异也有统计学意义(P＜0.01);DEX组Wnt2基因mRNA表达与对照组相比未见统计学差异(P＞0.05)。
4.Westem-blot结果:大剂量DEX多程组胞浆GSK-3β蛋白表达量较对照组下调(P＜0.05);DEX组胞浆β-catenin蛋白表达量较对照组明显下调(P＜0.01),胞核β-catenin蛋白表达量则较对照组上调(P＜0.05)。随着DEX剂量的增大、次数的增多,胞浆β-catenin蛋白表达量不断减低而胞核β-catenin蛋白表达量不断增多。
5.免疫组化结果:对照组中β-catenin在肺间质和实质均有表达,其表达量均低于DEX组(P＜0.05)。对照组可见GSK-3β在肺间质和实质也均有表达且最为明显,其表达量明显高于DEX组(P＜0.05),并且小剂量DEX单程组中GSK-3β的表达明显高于其他DEX组,差异有统计学意义(P＜0.05)。
结论
1.产前给药DEX可以促进胎肺早期发育,小剂量、单程DEX即可促进胎鼠肺部成熟,增加用药剂量或次数虽然肺部发育成熟度有所提高但肺泡化受阻的现象也愈加明显——肺泡直径变大,肺泡间隔变薄,总肺泡数减少,肺组织呈大而空的征象。基底膜呈现逐渐由厚薄均一到厚薄不均、由完整到不连续甚至无法辨认的变化,基底膜的这种变化,影响了细胞的分化、增殖及与间质的交流。
2.产前给药DEX同时影响了Wnt信号途径中Wnt7b、Wnt5a、β-catenin及GSK-3β基因的mRNA和蛋白的表达。DEX可能通过上调子代胎肺中Wnt7b的表达,抑制GSK-3β基因的表达,使得β-catenin降解减少,同时下调Wnt5a的表达亦减少β-catenin降解,使其在胞浆中积聚进入核内,共同导致Wnt信号经典途径的异常。
3.产前给药DEX对胎肺形态发育的影响可能是通过地塞米松所致的Wnt信号转导途径障碍而发生。
Objective:Antenatal Dexamethasone(DEX)therapy can induce pneum dysplasia.Fetal lung development is effected by many signal transduction pathways.Among them,Wnt pathway has been shown to play important roles in the development of lung by regulating cell differentiation, proliferation and polarity.To investigate the effects of DEX on lung morphogenesis and Wnt signal transduction,premature rat models were used to compare the effects of various dosages and courses of DEX therapy on antenatal rat fetal lung development.
Methods:Twenty pregnant rats were given the medicin through five defferent ways,and the fetal rats were divided into five groups randomly. For the small dose and large dose single course DEX groups, intraperitoneal(i.p)0.5ml saline on the 16~(th)、17~(th)day and i.p with 0.4 mg/kg and 0.8 mg/kg DEX respectively on the 18~(th)day of gestation.For the small dose and large dose multiple courses DEX groups,i.p with 0.4 mg/kg and 0.8 mg/kg DEX respectively on the 16~(th)、17~(th)、18~(th)day of gestation.For the control group,each of the four rats was i.p with 0.5ml saline on the 16~(th),17~(th)and 18~(th)day of gestation.On the 19~(th)day of gestation,cesarean section were performed and the histological structures of fetal rat lungs of each pregnant rat were observed with light microscope and electronmicroscopy.The RT-PCR、Western-Blot and immunohistochemistry methods were used to detect the mRNA and protein level of Wnts,glycogen synthasekinase 3β(GSK-3β)and β-catenin genes.
Results:
1.Under the light microscope,less alveolar numbers,larger alveolar spaces and thinner alveolar septums(P＜0.01)were showed in the DEX groups compared with the control group.
2.Under electron microscopy,lamellar body and cellular organs such as bioblast in endochylema of the DEX groups were more common compared with the control group.Lamellar body in the DEX groups was more anachromasis and condensed compared with the control group.With the increased DEX usage of the doses and courses,the basement membrane showed from completing to discontinuation, from uniform to anisouniform.
3.RT-PCR results:the mRNA level of Wnt7b andβ-catenin genes were significantly enhanced in study groups compared with those of the control group(P＜0.05)While the expressions of Wnt5a、GSK-3βwere downregulated in study groups compared with controls (P＜0.05).But there was no statistic difference in the expressions of Wnt2 between the DEX groups and control group.
4.Western-blot results:the expressions of GSK-3βprotein in cytoplasm of the study groups reduced gradually(P＜0.05)whileβ-catenin's in cytoplasm reduced(P＜0.01)andβ-catenin's in the nucleus enhanced(P＜0.01).
5.Immunohistochemistry results:β-catenin was expressed in mesenchyme and pulmonary alveolus in the control group.The expressions ofβ-catenin in control group were lower compared with the DEX groups(P＜0.05).GSK-3βwas also expressed in mesenchyme and pulmonary alveolus in the control group.The expressions ofβ-catenin in the control group were much higher compared with the DEX groups(P＜0.05).
Conclusions:
1.Antenatal DEX therapy can improve the fetal lung development.Even the small and single dosage of DEX may induce the fetal lung mature. Increasing the doses and courses of DEX not only improves the level of the fetal lung development,but also has negative effect on rat fetal lung morphogenesis.For example,reduction in alveolar numbers, alteration of alveolar space and septum.The basement membrane showed from completing to discontinuation,from uniform to anisouniform.These changes caused the cell differentiation, proliferation,and polarity,even the interactions between basement membrane and mesenchyme.
2.Antenatal DEX therapy changed the expressions of the mRNA and the protein of Wnt7b、Wnt 5a、β-catenin and GSK-3βgenes in the 19~(th) day of rat embryos.
3.Wnt pathway may involved in the effects of DEX therapy on rat fetal lung morphogenesis.
产前应用地塞米松(DEX)可以抑制炎症反应、促Ⅱ型肺泡细胞成熟、增加肺表面活性物质合成并促其分泌,减少早产儿呼吸窘迫综合症(RDS)的发生,同时也存在阻碍肺发育的现象。胚胎时期的肺发育受到多条信号途径影响,其中Wnt信号转导途径参与调控肺上皮细胞和间质细胞分化、细胞增殖及凋亡等过程,在肺发育过程中起着重要作用。因此我们采用早产鼠肺模型,比较产前给予不同剂量、不同疗程地塞米松对大鼠胎肺形态发育及Wnt信号转导途径的影响。
方法
20只孕鼠分5种情况用药,胎鼠分5组,每组约16只。小剂量、大剂量DEX单程组:分别于孕16、17天注射等量生理盐水,孕18天腹腔注射DEX 0.4 mg/kg、0.8 mg/kg;小剂量、大剂量DEX多程组:分别于孕16、17、18天腹腔注射DEX 0.4 mg/kg、0.8 mg/kg。注射时DEX均用生理盐水稀释至0.5ml;其中小剂量、大剂量DEX单程组和多程组统称为DEX组。对照组:孕16、17、18天注射等量生理盐水。雌鼠孕19天时破宫后取胎鼠肺组织作为早产鼠肺模型,每只孕鼠随机取4只早产鼠,共16只取全肺分别通过光镜观察及电镜技术,分析比较各组胎肺形态发育的差异、RT-PCR方法检测Wnt信号转导途径中Wnt7b、Wnt5a、Wnt2、GSK-3β和β-catenin基因mRNA的表达,Western-Blot、免疫组化方法检测GSK-3β、β-catenin蛋白表达量和表达部位。
结果
1.HE染色光镜观察结果:DEX组与对照组相比,肺泡数目减少、肺泡腔结构扩大,肺泡间隔厚度变薄、周围结缔组织减少。其中小剂量DEX单程、多程组及大剂量DEX单程、多程组每视野肺泡计数,平均肺泡间隔厚度均低于对照组(P＜0.01),平均肺泡表面积均高于对照组(P＜0.01)。
2.电镜观察结果:DEX组Ⅱ型肺泡上皮细胞内可见板层小体且染色深、致密,胞质内线粒体等细胞器增多;而对照组内难见板层小体、细胞器数目减少。随着DEX用药剂量和次数的增多,板层小体数目逐渐增多,基底膜则呈现由完整到断裂不连续、由厚薄均一到厚薄不均甚至无法辨认的变化,且大剂量DEX组中的线粒体数目较小剂量组少,内质网也有扩张。
3.RT-PCR结果:DEX组胎肺Wnt7b及β-catenin基因mRNA的表达量均显著高于对照组(P＜0.05);GSK-3β表达量较对照组减少(P＜0.05)。小剂量DEX单程、多程组及大剂量DEX单程组Wnt5a基因mRNA表达均低于对照组(P＜0.05),不同剂量DEX多程组之间差异也有统计学意义(P＜0.01);DEX组Wnt2基因mRNA表达与对照组相比未见统计学差异(P＞0.05)。
4.Westem-blot结果:大剂量DEX多程组胞浆GSK-3β蛋白表达量较对照组下调(P＜0.05);DEX组胞浆β-catenin蛋白表达量较对照组明显下调(P＜0.01),胞核β-catenin蛋白表达量则较对照组上调(P＜0.05)。随着DEX剂量的增大、次数的增多,胞浆β-catenin蛋白表达量不断减低而胞核β-catenin蛋白表达量不断增多。
5.免疫组化结果:对照组中β-catenin在肺间质和实质均有表达,其表达量均低于DEX组(P＜0.05)。对照组可见GSK-3β在肺间质和实质也均有表达且最为明显,其表达量明显高于DEX组(P＜0.05),并且小剂量DEX单程组中GSK-3β的表达明显高于其他DEX组,差异有统计学意义(P＜0.05)。
结论
1.产前给药DEX可以促进胎肺早期发育,小剂量、单程DEX即可促进胎鼠肺部成熟,增加用药剂量或次数虽然肺部发育成熟度有所提高但肺泡化受阻的现象也愈加明显——肺泡直径变大,肺泡间隔变薄,总肺泡数减少,肺组织呈大而空的征象。基底膜呈现逐渐由厚薄均一到厚薄不均、由完整到不连续甚至无法辨认的变化,基底膜的这种变化,影响了细胞的分化、增殖及与间质的交流。
2.产前给药DEX同时影响了Wnt信号途径中Wnt7b、Wnt5a、β-catenin及GSK-3β基因的mRNA和蛋白的表达。DEX可能通过上调子代胎肺中Wnt7b的表达,抑制GSK-3β基因的表达,使得β-catenin降解减少,同时下调Wnt5a的表达亦减少β-catenin降解,使其在胞浆中积聚进入核内,共同导致Wnt信号经典途径的异常。
3.产前给药DEX对胎肺形态发育的影响可能是通过地塞米松所致的Wnt信号转导途径障碍而发生。
Objective:Antenatal Dexamethasone(DEX)therapy can induce pneum dysplasia.Fetal lung development is effected by many signal transduction pathways.Among them,Wnt pathway has been shown to play important roles in the development of lung by regulating cell differentiation, proliferation and polarity.To investigate the effects of DEX on lung morphogenesis and Wnt signal transduction,premature rat models were used to compare the effects of various dosages and courses of DEX therapy on antenatal rat fetal lung development.
Methods:Twenty pregnant rats were given the medicin through five defferent ways,and the fetal rats were divided into five groups randomly. For the small dose and large dose single course DEX groups, intraperitoneal(i.p)0.5ml saline on the 16~(th)、17~(th)day and i.p with 0.4 mg/kg and 0.8 mg/kg DEX respectively on the 18~(th)day of gestation.For the small dose and large dose multiple courses DEX groups,i.p with 0.4 mg/kg and 0.8 mg/kg DEX respectively on the 16~(th)、17~(th)、18~(th)day of gestation.For the control group,each of the four rats was i.p with 0.5ml saline on the 16~(th),17~(th)and 18~(th)day of gestation.On the 19~(th)day of gestation,cesarean section were performed and the histological structures of fetal rat lungs of each pregnant rat were observed with light microscope and electronmicroscopy.The RT-PCR、Western-Blot and immunohistochemistry methods were used to detect the mRNA and protein level of Wnts,glycogen synthasekinase 3β(GSK-3β)and β-catenin genes.
Results:
1.Under the light microscope,less alveolar numbers,larger alveolar spaces and thinner alveolar septums(P＜0.01)were showed in the DEX groups compared with the control group.
2.Under electron microscopy,lamellar body and cellular organs such as bioblast in endochylema of the DEX groups were more common compared with the control group.Lamellar body in the DEX groups was more anachromasis and condensed compared with the control group.With the increased DEX usage of the doses and courses,the basement membrane showed from completing to discontinuation, from uniform to anisouniform.
3.RT-PCR results:the mRNA level of Wnt7b andβ-catenin genes were significantly enhanced in study groups compared with those of the control group(P＜0.05)While the expressions of Wnt5a、GSK-3βwere downregulated in study groups compared with controls (P＜0.05).But there was no statistic difference in the expressions of Wnt2 between the DEX groups and control group.
4.Western-blot results:the expressions of GSK-3βprotein in cytoplasm of the study groups reduced gradually(P＜0.05)whileβ-catenin's in cytoplasm reduced(P＜0.01)andβ-catenin's in the nucleus enhanced(P＜0.01).
5.Immunohistochemistry results:β-catenin was expressed in mesenchyme and pulmonary alveolus in the control group.The expressions ofβ-catenin in control group were lower compared with the DEX groups(P＜0.05).GSK-3βwas also expressed in mesenchyme and pulmonary alveolus in the control group.The expressions ofβ-catenin in the control group were much higher compared with the DEX groups(P＜0.05).
Conclusions:
1.Antenatal DEX therapy can improve the fetal lung development.Even the small and single dosage of DEX may induce the fetal lung mature. Increasing the doses and courses of DEX not only improves the level of the fetal lung development,but also has negative effect on rat fetal lung morphogenesis.For example,reduction in alveolar numbers, alteration of alveolar space and septum.The basement membrane showed from completing to discontinuation,from uniform to anisouniform.These changes caused the cell differentiation, proliferation,and polarity,even the interactions between basement membrane and mesenchyme.
2.Antenatal DEX therapy changed the expressions of the mRNA and the protein of Wnt7b、Wnt 5a、β-catenin and GSK-3βgenes in the 19~(th) day of rat embryos.
3.Wnt pathway may involved in the effects of DEX therapy on rat fetal lung morphogenesis.
引文
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12.Pua ZJ,Stonestreet BS,Cullen et al.Histochemical analyses of altered fetal lung development following single vs multiple courses of antenatal steroids[J].J Histochem Cytochem,2005,53:1469-1479.
13.Garber SJ,Zhang H,Foley JP,et al.Hormonal regulation of alveolariza- tion:structure-function correlation[J].Respir Res,2006,7(1):47.
14.Polk DH,Ikegai M,Jobe AH,et al.Preterm lung function after retreatment with atenatal betamethasone in preterm lambs[J].Am J Obstet Gynecol,1997,176(2):308-315.
15.Lin Y,Liu A,Zhang S,Ruusunen T,Kreidberg JA,Peltoketo H,Drummond I,Vainio S:Induction of ureter branching as a response to Wnt-2b signaling during early kidney organogenesis.Dev Dyn.2001,222:26-39.
16.Chen W,ten Berge D,Brown J,et al.Dishevelled 2 recruits beta-arrestin 2 to mediate Wnt5A-stimulated endocytosis of Frizzled.Science,2003,301(5638):1391-1394.
17.Liu J,Stevens J,Rote CA,et al.Siah-1 mediates a novel beta-catenin degradation pathway linking p53 to the adenomatous polyposis coli protein.Mol Cell,2001,7(5):927-936.
18.Topol L,Jiang X,Choi H,et al.Wnt-5a inhibits the canonical Wnt pathway by promoting GSK-3--independent beta-catenin degradation. J Cell Biol, 2003, 162(5): 899-908.
19. Monkley SJ, Delaney SJ, Pennisi DJ, Christiansen JH, Wainwright BJ:Targeted disruption of the Wnt2 gene results in placentation defects.Development 1996, 122:3343-3353.
20. Li C, Xiao J, Hormi K, Borok Z, Minoo P: Wnt5a participates in distal lung morphogenesis. Dev Biol 2002,248:68-81.
21. Shu WS, Jiang YQ, Lu MM,et al. Wnt7b regulates mesenchymal proliferation and vascular development in the lung. Development,2002, 129:4831-4842.
22. Parr BA, Cornish VA, Cybulsky MI, McMahon AP: Wnt7b regulates placental development in mice. Dev Biol 2001, 237:324-332.
23. Mucenski ML, Wert SE, Nation JM, et,al. Beta-Catenin is required for specification of proximal/distal cell fate during lung morphogenesis. J Biol Chem, 2003,278: 40231-40238.
24. Mucenski ML, Nation JM, Thitoff AR, et al. Beta-Catenin regulates differentiation of respiratory epithelial cells in vivo. Am J Physiol Lung Cell Mol Physiol, 2005, 289:L971-L979.
1.Groenman F,Unger S,Post M.The Molecular Basis for Abnormal Human Lung Development.Biol Neonate,2005,87:164-177.
2.Morrisey EE.Wnt Signaling and Pulmonary Fibrosis.American Journal of Pathology,2003,162(5):1393-1397.
3.Clark JC,Tichelaar JW,Wert SE,et al.FGF-10 disrupts lung morphogenesis and causes pulmonary adenomas in vivo.Am J Physiol Lung Cell Mol Physiol,2001,280:L705-L715.
4.Ohuchi H,Hori Y,Yamasaki M,et al.FGF10 Acts as a Major Ligand for FGF Receptor2 Ⅲb in Mouse Multi-Organ Development.Biochemical and Biophysical Research Communications.2000,277:643-649.
5.Deimling J,Thompson K,Tseu I,et al.Mesenchymal Maintenance of Distal Epithelial Cell Phenotype During Late Fetal Lung Development.Am J Physiol Lung Cell Mol Physiol.2007,292(3):L725-741.
6.Tichelaar JW,Lu W,and Whitsett JA.Conditional Expression of Fibroblast Growth Factor-7 in the Developing and Mature Lung.J Biol Chem,2000,275(16):11858-11864.
7.Hokuto I,Perl AKT and Whitsett JA.Prenatal,but Not Postnatal,Inhibition of Fibroblast Growth Factor Receptor Signaling Causes Emphysema.J.Biol.Chem,2003,278:415-421.
8.Bernadette Chailley-Heu,Boucherat O,et al.FGF-18 is upregulated in the postnatal rat lung and enhances elastogenesis in myofibroblasts.Am J Physiol Lung Cell Mol Physiol,2005,288:L43-L51.
9.吴桐,庞小颖,张浩.Wnt信号途径的分子机制.食品与药品,2006,8(7):5-8.
10.Pongracz' JE and Stockley RA.Wnt signalling in lung development and diseases.Respir Res,2006,36(9):2376-2383.
11.Mucenski ML,Wert SE,Natian JM,et al.β-catenin is required for the specification of proximal/distal cell fate during lung morphogenesis.J.Biol.Chem.2003,278(41):40231-40238.
12. Shu W, Jiang YQ, Lu MM,et al. Wnt7b regulates mesenchymal proliferation vascular development in the lung. Dev. 2002, 129:4831-4842.
13. Li C, Xiao J, Hormi K, et al. Wnt5a participates in distal lung morphogenesis. Dev. Biol,2002,248:68-81.
14. Levay-Young BK,Navre M. Growth and developmental regulation of Wnt2 gene in mesenchymal cells of fetal lung. The American Physiological Society, 1992,L672-L684.
15. Cordray P and Satterwhite DJ. TGF-β Induces Novel Lef-1 Splice Variants Through a Smad-Independent Signaling Pathway. Dev.Dynaics,2005, 232:969-978.
16. Torday JS, Rehan VK. Up-regulation of fetal rat lung parathyroid hormone-related protein gene regulatory network down-regulates the Sonic Hedgehog/Wnt/betacatenin gene regulatory network.Pediatr Res. 2006 ,60(4):382-388.
17. Unger S , Copland I, Tibboel J. Down-Regulation of Sonic Hedgehog Expression in Pulmonary Hypoplasia Is Associated with Congenital Diaphragmatic Hernia. American Journal of Pathology. 2003,162: 547 -555.
18. Bellusci S, Furuta Y, Rush MG, et al. Involvement of Sonic hedgehog (Shh) in mouse enbryonic lung growth and morphogenesis. Dev., 1997,124:53-63.
19.Shannon JM,Hyatt BA.Epithelial-Mesenchymal Interactions in the Developing Lung.Annu.Rev.Physiol,2004,66:625-645.
20.Lu MM,Yang H,Zhang L.The bone morphogenic protein antagonist gremlin regulates proximal-distal patterning of the lung.Dev.Dyn.2001,222:667-680.
21.Shi W,Zhao J,Anderson KD.Gremlin negatively modulates BMP-4 induction of embryonic mouse lung branching morphogenesis.Am.J.Physiol.Lung Cell Mol.Physiol.2001,280:L1030-1039.
22.Gebb SA and Shannon JM.Tissue interactions mediate early events in pulmonary vasculogenesis.Dev Dyn.2000,217(2):159-169.
23.巢建新,庄德义.支气管肺发育不良的研究进展。国外医学儿科学分册.2005,32(4):207-210.
24.Jankov RP,Keith Tanswell A.Growth factors,postnatal lung growth and bronchopulmonary dysplasia.Paediatr Respir.2004;5(suppl A):S265-S275.
25.Bhatt AJ,Pryhuber GS,Huyck H,et al.Disrupted Pulmonary Vasculature and Decreased Vascular Endothelial Growth Factor,Flt-1,and TIE-2 in Human Infants Dying with Bronchopulmonary Dysplasia.Am.J.Respir.Crit Care Med.2001,164(10):1971-1980.
26. Lassus P, Turanlahti M, Heikkila P,et al. Pulmonary Vascular Endothelial Growth Factor and Flt-1 in Fetuses, in Acute and Chronic Lung Disease, and in Persistent Pulmonary Hypertension of the Newborn. Am J Respir Crit Care Med.2003, 168 (4):501-502.
27. Gerber HP, Hillan KJ, Ryan AM,et al. VEGF is required for growth and survival in neonatal mice. Dev. 1999,126: 1149-1159.
28. Abman SH. Bronchopulmonary dysplasia: 'Avascular hypothesis'. Am J Respir Crit Care Med,2001,164: 1755-1756.
29. Le Cart C, Cayabyab R, Buckley S, et al. Bioactive transforming growth factor-beta in the lungs of extremely low birth weight neonates predicts the need for homeoxygen supplementation. Biol.Neonat. 2000,7:217-223.
30. Groenman F, Unger S, Post M. The Molecular Basis for Abnormal Human Lung Development. Biol Neonate. 2005, 87:164-177.
31. Jankov RP, Luo X, Campbell A, et al. Fibroblast growth factor receptor-1 and neonatal compensatory lung growth after exposure to 95% oxygen. Am J Respir Crit Care Med.2003,167:1554-1561.
32. Danan C, Franco ML, Jarreau PH, et al. High concentrations of keratinocyte growth factor in airways of premature infants predicted absence of bronchopulmonary dysplasia. Am J Respir Crit Care Med.2002,165:1384-1387.
33.Chetty A, Cao GJ, Nielsen HC.Insulin-like Growth Factor-I signaling mechanisms,type I collagen and alpha smooth muscle actin in human fetal lung fibroblasts. Pediatr Res. 2006, 60 (4):389-394.
34. Warburton D, Bellusci S, Del Moral PM, et al. Growth factor signaling in lung morphogenetic centers: automaticity, stereotypy and symmetry. Respir Res.2003,4:501-517.
35. Bourbon J, Boucherat O, Chailley-Heu B, et al.Control Mechanisms of Lung Alveolar Development and Their Disorders in Bronchopulmonary Dysplasia. Pediatr Res. 2005,57: 2.
2.Cognitive L,Peter H.Suppression of cell proliferation and programmed cell death by dexamethasone during postnatal lung development.Am J Physiol,2002,282:L477-L483.
3.朱翠平、马祖祥.地塞米松对早产儿支气管肺发育不良预防作用的荟萃分析.广东医学,2006,27:415-418.
4.Cedric L,Peter H.Suppression of cell proliferation and programmed cell death by dexamethasone during postnatal lung development.Am J Physiol,2002,282:L477-L483.
5.陈尚勤、李昌崇、陈超.产前重复糖皮质激素治疗对肺结构发育的影响.国外医学呼吸系统分册,2004,24:233-236.
6.Shu WS,Jiang YQ,Lu MM,et al.Wnt7b regulates mesenchymal proliferation and vascular development in the lung.Development,2002,129:4831-4842.
7.Weidenfeld J,Shu W,Zhang L,et al.The WNT7B promoter is regulated by TTF-1,GATA6,and Foxa2 in lung epithelium.J Biol Chem,2002,277:21061-21070.
8.Shannon JM and Hyatt BA.Epithelial-Mesenchymal Interactions In The Developing Lung.Annu.Rev.Physiol,2004.66:625-45.
9.Lebechel D,Malpell S,Cardoso WV.Fibroblast growth factor interactions in the developing lung.Mechanisms of Development,1999,86:125-136.
10.庄立岩,郭应禄,张志文.Wnt基因与生物发育和肿瘤发生.生物化学与生物物理进展,1999,26:117-121.
11.吴桐,庞小颖,张浩.Wnt信号途径的分子机制.食品与药 品,2006,8:5-8.
12.Lin Y, Liu A, Zhang S, et al. Induction of ureter branching as a response to Wnt-2b signaling during early kidney organogenesis. Dev Dyn, 2001, 222:26-39.
13.Monkley SJ, Delaney SJ, Pennisi DJ, et al. Targeted disruption of the Wnt2 gene results in placentation defects.Development,1996, 122:3343-3353.
14.Li C, Xiao J, Hormi K, et al. Wnt5a participates in distal lung morphogenesis. Dev Biol, 2002,248:68-81.
15.Parr BA, Cornish VA, Cybulsky MI, et al. Wnt7b regulates placental development in mice. Dev Biol ,2001,237:324-332.
16.Cordray P and Satterwhite DJ.TGF-p Induces Novel Lef-1 Splice Variants Through a Smad-Independent Signaling Pathway. Dev Dyn ,2005, 232:969-978.
1.Kiran PS,Dutta S,Narang A,et al.Multiple courses of antenatal steroids[J].Indian Jourmal of Pidiatrics.2007,74(3):41-47.
2.National Institutes of Health Consensus Development Panel.Effect of corticosteroids for fetal maturation on perinatal outcomes.JAMA.1994,273:413-418.
3.朱翠平,马祖祥.地塞米松对早产儿支气管肺发育不良预防作用的荟萃分析.广东医学,2006,27:415-418.
4.Johnson FJ,Reynolds,L J,Toward TJ.Elastolytic activity and alveolar epithelial type-1 cell damage after chronic LPS inhalation:effects of dexamethasone and rolipram.Toxicol Appl Pharmacol,2005,207:257-265.
5.池美珠,陈超,钱燕,等.产前重复激素治疗对仔鼠星形胶质细胞发育的影响.实用儿科临床杂志,2006,21:98-100.
6.Ozdemir H,Guvenal T,Cetin M,et al.A placebo-controlled comparison of effects of repetitive doses of betamethasone and dexamethasone on lung maturation and lung,liver,and body weights of mouse pups[J].Pediatr Res,2003,53(1):98-103.
7.Satoru OK,Tadashi MA.Antenatal dexamethasone administration impairs normal postnatal lung growth in rats[J].Pediatric Res,2001,49(6):777-781.
8.Willet KE,Jobe All,Ikegami M,et al.Antenatal endotoxin and glucocorticoid effects on lung morphometry in preterm lambs[J].Pediatr Res,2000,48(4):782-788.
9.陈尚勤,李昌崇,郑亚兵,等.产前给予地塞米松对仔鼠肺泡上皮细胞基底膜的影响[J].中国药理学与毒理学杂志,2005,19(3):209-213.
10.Arai H,Kikuchi W,Ishida A,Takada G.Dexamethasone-induced prenatal alveolar wall thinning is associated with a decrease in EⅢA+fibronectin isoform in the fetal rat lung[J].Biol Neonate,2005,87(2):113-120.
11.阚清,顾筱琪,刘茹等.产前给药沐舒坦、地塞米松对大鼠胎肺形态发育的影响[J].南京医科大学学报(自然科学版),2007,27(3):232-234,245.
12.Pua ZJ,Stonestreet BS,Cullen et al.Histochemical analyses of altered fetal lung development following single vs multiple courses of antenatal steroids[J].J Histochem Cytochem,2005,53:1469-1479.
13.Garber SJ,Zhang H,Foley JP,et al.Hormonal regulation of alveolariza- tion:structure-function correlation[J].Respir Res,2006,7(1):47.
14.Polk DH,Ikegai M,Jobe AH,et al.Preterm lung function after retreatment with atenatal betamethasone in preterm lambs[J].Am J Obstet Gynecol,1997,176(2):308-315.
15.Lin Y,Liu A,Zhang S,Ruusunen T,Kreidberg JA,Peltoketo H,Drummond I,Vainio S:Induction of ureter branching as a response to Wnt-2b signaling during early kidney organogenesis.Dev Dyn.2001,222:26-39.
16.Chen W,ten Berge D,Brown J,et al.Dishevelled 2 recruits beta-arrestin 2 to mediate Wnt5A-stimulated endocytosis of Frizzled.Science,2003,301(5638):1391-1394.
17.Liu J,Stevens J,Rote CA,et al.Siah-1 mediates a novel beta-catenin degradation pathway linking p53 to the adenomatous polyposis coli protein.Mol Cell,2001,7(5):927-936.
18.Topol L,Jiang X,Choi H,et al.Wnt-5a inhibits the canonical Wnt pathway by promoting GSK-3--independent beta-catenin degradation. J Cell Biol, 2003, 162(5): 899-908.
19. Monkley SJ, Delaney SJ, Pennisi DJ, Christiansen JH, Wainwright BJ:Targeted disruption of the Wnt2 gene results in placentation defects.Development 1996, 122:3343-3353.
20. Li C, Xiao J, Hormi K, Borok Z, Minoo P: Wnt5a participates in distal lung morphogenesis. Dev Biol 2002,248:68-81.
21. Shu WS, Jiang YQ, Lu MM,et al. Wnt7b regulates mesenchymal proliferation and vascular development in the lung. Development,2002, 129:4831-4842.
22. Parr BA, Cornish VA, Cybulsky MI, McMahon AP: Wnt7b regulates placental development in mice. Dev Biol 2001, 237:324-332.
23. Mucenski ML, Wert SE, Nation JM, et,al. Beta-Catenin is required for specification of proximal/distal cell fate during lung morphogenesis. J Biol Chem, 2003,278: 40231-40238.
24. Mucenski ML, Nation JM, Thitoff AR, et al. Beta-Catenin regulates differentiation of respiratory epithelial cells in vivo. Am J Physiol Lung Cell Mol Physiol, 2005, 289:L971-L979.
1.Groenman F,Unger S,Post M.The Molecular Basis for Abnormal Human Lung Development.Biol Neonate,2005,87:164-177.
2.Morrisey EE.Wnt Signaling and Pulmonary Fibrosis.American Journal of Pathology,2003,162(5):1393-1397.
3.Clark JC,Tichelaar JW,Wert SE,et al.FGF-10 disrupts lung morphogenesis and causes pulmonary adenomas in vivo.Am J Physiol Lung Cell Mol Physiol,2001,280:L705-L715.
4.Ohuchi H,Hori Y,Yamasaki M,et al.FGF10 Acts as a Major Ligand for FGF Receptor2 Ⅲb in Mouse Multi-Organ Development.Biochemical and Biophysical Research Communications.2000,277:643-649.
5.Deimling J,Thompson K,Tseu I,et al.Mesenchymal Maintenance of Distal Epithelial Cell Phenotype During Late Fetal Lung Development.Am J Physiol Lung Cell Mol Physiol.2007,292(3):L725-741.
6.Tichelaar JW,Lu W,and Whitsett JA.Conditional Expression of Fibroblast Growth Factor-7 in the Developing and Mature Lung.J Biol Chem,2000,275(16):11858-11864.
7.Hokuto I,Perl AKT and Whitsett JA.Prenatal,but Not Postnatal,Inhibition of Fibroblast Growth Factor Receptor Signaling Causes Emphysema.J.Biol.Chem,2003,278:415-421.
8.Bernadette Chailley-Heu,Boucherat O,et al.FGF-18 is upregulated in the postnatal rat lung and enhances elastogenesis in myofibroblasts.Am J Physiol Lung Cell Mol Physiol,2005,288:L43-L51.
9.吴桐,庞小颖,张浩.Wnt信号途径的分子机制.食品与药品,2006,8(7):5-8.
10.Pongracz' JE and Stockley RA.Wnt signalling in lung development and diseases.Respir Res,2006,36(9):2376-2383.
11.Mucenski ML,Wert SE,Natian JM,et al.β-catenin is required for the specification of proximal/distal cell fate during lung morphogenesis.J.Biol.Chem.2003,278(41):40231-40238.
12. Shu W, Jiang YQ, Lu MM,et al. Wnt7b regulates mesenchymal proliferation vascular development in the lung. Dev. 2002, 129:4831-4842.
13. Li C, Xiao J, Hormi K, et al. Wnt5a participates in distal lung morphogenesis. Dev. Biol,2002,248:68-81.
14. Levay-Young BK,Navre M. Growth and developmental regulation of Wnt2 gene in mesenchymal cells of fetal lung. The American Physiological Society, 1992,L672-L684.
15. Cordray P and Satterwhite DJ. TGF-β Induces Novel Lef-1 Splice Variants Through a Smad-Independent Signaling Pathway. Dev.Dynaics,2005, 232:969-978.
16. Torday JS, Rehan VK. Up-regulation of fetal rat lung parathyroid hormone-related protein gene regulatory network down-regulates the Sonic Hedgehog/Wnt/betacatenin gene regulatory network.Pediatr Res. 2006 ,60(4):382-388.
17. Unger S , Copland I, Tibboel J. Down-Regulation of Sonic Hedgehog Expression in Pulmonary Hypoplasia Is Associated with Congenital Diaphragmatic Hernia. American Journal of Pathology. 2003,162: 547 -555.
18. Bellusci S, Furuta Y, Rush MG, et al. Involvement of Sonic hedgehog (Shh) in mouse enbryonic lung growth and morphogenesis. Dev., 1997,124:53-63.
19.Shannon JM,Hyatt BA.Epithelial-Mesenchymal Interactions in the Developing Lung.Annu.Rev.Physiol,2004,66:625-645.
20.Lu MM,Yang H,Zhang L.The bone morphogenic protein antagonist gremlin regulates proximal-distal patterning of the lung.Dev.Dyn.2001,222:667-680.
21.Shi W,Zhao J,Anderson KD.Gremlin negatively modulates BMP-4 induction of embryonic mouse lung branching morphogenesis.Am.J.Physiol.Lung Cell Mol.Physiol.2001,280:L1030-1039.
22.Gebb SA and Shannon JM.Tissue interactions mediate early events in pulmonary vasculogenesis.Dev Dyn.2000,217(2):159-169.
23.巢建新,庄德义.支气管肺发育不良的研究进展。国外医学儿科学分册.2005,32(4):207-210.
24.Jankov RP,Keith Tanswell A.Growth factors,postnatal lung growth and bronchopulmonary dysplasia.Paediatr Respir.2004;5(suppl A):S265-S275.
25.Bhatt AJ,Pryhuber GS,Huyck H,et al.Disrupted Pulmonary Vasculature and Decreased Vascular Endothelial Growth Factor,Flt-1,and TIE-2 in Human Infants Dying with Bronchopulmonary Dysplasia.Am.J.Respir.Crit Care Med.2001,164(10):1971-1980.
26. Lassus P, Turanlahti M, Heikkila P,et al. Pulmonary Vascular Endothelial Growth Factor and Flt-1 in Fetuses, in Acute and Chronic Lung Disease, and in Persistent Pulmonary Hypertension of the Newborn. Am J Respir Crit Care Med.2003, 168 (4):501-502.
27. Gerber HP, Hillan KJ, Ryan AM,et al. VEGF is required for growth and survival in neonatal mice. Dev. 1999,126: 1149-1159.
28. Abman SH. Bronchopulmonary dysplasia: 'Avascular hypothesis'. Am J Respir Crit Care Med,2001,164: 1755-1756.
29. Le Cart C, Cayabyab R, Buckley S, et al. Bioactive transforming growth factor-beta in the lungs of extremely low birth weight neonates predicts the need for homeoxygen supplementation. Biol.Neonat. 2000,7:217-223.
30. Groenman F, Unger S, Post M. The Molecular Basis for Abnormal Human Lung Development. Biol Neonate. 2005, 87:164-177.
31. Jankov RP, Luo X, Campbell A, et al. Fibroblast growth factor receptor-1 and neonatal compensatory lung growth after exposure to 95% oxygen. Am J Respir Crit Care Med.2003,167:1554-1561.
32. Danan C, Franco ML, Jarreau PH, et al. High concentrations of keratinocyte growth factor in airways of premature infants predicted absence of bronchopulmonary dysplasia. Am J Respir Crit Care Med.2002,165:1384-1387.
33.Chetty A, Cao GJ, Nielsen HC.Insulin-like Growth Factor-I signaling mechanisms,type I collagen and alpha smooth muscle actin in human fetal lung fibroblasts. Pediatr Res. 2006, 60 (4):389-394.
34. Warburton D, Bellusci S, Del Moral PM, et al. Growth factor signaling in lung morphogenetic centers: automaticity, stereotypy and symmetry. Respir Res.2003,4:501-517.
35. Bourbon J, Boucherat O, Chailley-Heu B, et al.Control Mechanisms of Lung Alveolar Development and Their Disorders in Bronchopulmonary Dysplasia. Pediatr Res. 2005,57: 2.