Spatial and temporal patterns of c-kit positive cells in embryonic lungs.
BACKGROUND
It has been reported that the smooth muscles in fetal airways exhibit spontaneous phasic contractions throughout gestation. However, the mechanism of these spontaneous contractions is unknown. In the bowel wall, interstitial cells of Cajal (ICCs), which are derived from c-kit positive precursor cells, play an important role as pacemaker cells responsible for the spontaneous, rhythmic activity in the smooth muscle cells. In this study, we investigated the spatial and temporal expression patterns of c-kit positive cells in the embryonic lung and its relationship to the smooth muscle cells surrounding the trachea and the bronchus.


METHODS
Rat fetuses were removed from timed pregnant dams on embryonic days (E) 11.5, 13.5, 15.5, and 17.5. Immunohistochemical studies with anti c-kit antibody and anti α-SMA antibody were carried out using frozen sections.


RESULTS
A small number of c-kit positive cells were observed in the mesenchyme of the lung bud on day E 11.5. They were markedly increased in number on day E 13.5. On day E 15.5 and on day E 17.5, strong c-kit expressions were observed on the vascular wall and moderate expressions in the mesenchyme. C-kit positive cells co-localized with α-SMA positive smooth muscle cells surrounding the airway epithelium.


CONCLUSIONS
Co-localization of c-kit positive cells and airway smooth muscles in the fetal lung suggests that c-kit positive cells may play an important role in the spontaneous contractions of fetal airways. C-kit expressions in the fetal pulmonary vascular wall suggest that these cells may play an important role in vasculogenesis and angiogenesis of the embryonic lung.
National Children's Research Centre, Our Lady's Children's Hospital, University College of Dublin, Crumlin, Dublin 12, Ireland.
Toko
T
Shinkai
Masato
M
Shinkai
Martina A
MA
Pirker
Sandra
S
Montedonico
Prem
P
Puri
D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D056885:Interstitial Cells of Cajal / Q000378:metabolism*; D008168:Lung / Q000196:embryology* / Q000378:metabolism; D008297:Male; D011247:Pregnancy; D011270:Pregnancy, Animal; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D019009:Proto-Oncogene Proteins c-kit