Effect of insulin-like growth factors on lung development in a nitrofen-induced CDH rat model.
OBJECTIVE
Both the mortality and morbidity associated with congenital diaphragmatic hernia (CDH) are mainly caused by pulmonary hypoplasia and persistent pulmonary hypertension. A previous study revealed that insulin-like growth factors (IGFs) play important roles in fetal lung development. The aim of this study was to investigate the effect of IGF-1 and IGF-2 on tissue cultures of fetal hypoplastic lungs obtained from nitrofen-induced CDH model rats.


METHODS
Pregnant rats were exposed to nitrofen on day 9 of gestation (D9). Fetuses were harvested on D18 by caesarian section. Lung specimens of the CDH (+) fetus were divided into three groups; control, IGF-1, and IGF-2. The specimens from the control group were cultured in culture medium without IGFs. The IGF-1 group specimens were cultured with IGF-1 (500 ng/ml), and those in the IGF-2 group were cultured with IGF-2 (500 ng/ml). The mRNA expression of TTF-1, T1α and α-SMA were analyzed in each group using real-time RT-PCR after 24 and 48 h of incubation. Immunohistochemical staining of these markers was also assessed for each of the cultured specimens.


RESULTS
There was a significant increase in the expression of both TTF-1 and T1α mRNA in the IGF-2 group, in comparison to the control group after 48 h of culture. Immunohistochemical staining revealed that the cell morphology was changed from cuboidal to squamous type in the IGF-2 group.


CONCLUSIONS
An increased mRNA expression of the markers related to type 1 and 2 alveolar epithelial cells, and morphological changes in the epithelial cells were observed in the IGF-2 group. The administration of IGF-2 to nitrofen-induced hypoplastic lungs might lead to alveolar maturation, which thus results in their improved development.
Department of Pediatric Surgery, Reproductive and Developmental Medicine, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka, 812-8582, Japan. esumi@pedsurg.med.kyushu-u.ac.jp
Genshiro
G
Esumi
Kouji
K
Masumoto
Risa
R
Teshiba
Kouji
K
Nagata
Yoshiaki
Y
Kinoshita
Haruyoshi
H
Yamaza
Kazuaki
K
Nonaka
Tomoaki
T
Taguchi
D000199:Actins / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006548:Hernia, Diaphragmatic / Q000139:chemically induced / Q000196:embryology / Q000378:metabolism; D065630:Hernias, Diaphragmatic, Congenital; D007150:Immunohistochemistry; D008168:Lung / Q000187:drug effects / Q000196:embryology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics; D010647:Phenyl Ethers / Q000633:toxicity; D011247:Pregnancy; D011270:Pregnancy, Animal; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013002:Somatomedins / Q000494:pharmacology*; D000074482:Thyroid Nuclear Factor 1; D046509:Tissue Culture Techniques; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D000098853:Podoplanin
D000199:Actins; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; D010647:Phenyl Ethers; D012333:RNA, Messenger; D013002:Somatomedins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; C000614416:Nkx2-1 protein, rat; C092025:Pdpn protein, rat; D000098853:Podoplanin; C498862:Acta2 protein, rat; C007350:nitrofen