Expression of vascular endothelial growth factor and its receptors in the developing rat lung.
We examined the regulation of the expression of vascular endothelial growth factor (VEGF) and its specific receptors, fetal liver kinase receptor (Flk-1), and fms-like tyrosine kinase receptor (Flt-1) during formation of the capillary network in the developing rat lung. An immunohistochemical study of lung tissue from 19- and 21-d-old fetuses and 1-, 3-, 5-, 7-, and 14-d-old animals revealed that the level of expression of both VEGF and Flk-1 is significantly higher before birth (p < 0.0001) than after. Increased expression of Flt-1 on the first day after birth (p < 0.0001) suggests that this receptor might play an important role in capillary growth in the perinatal period. Immunostaining also revealed the colocalization of VEGF, Flt-1, and Flk-1 in endothelial cells of the lung capillaries at the ultrastructural level. The present studies revealed that VEGF and its two receptors are upregulated during the development of capillaries in the fetal and newborn rat lung.
Marszalek
A
A
First Department of Pathology, Oita Medical University, Hasama-machi, Oita-gun, Oita, 879-5593 Japan. yokoyama@oita-med.ac.jp
Daa
T
T
Kashima
K
K
Nakayama
I
I
Yokoyama
S
S
D000818:Animals; D000831:Animals, Newborn; D002196:Capillaries; D016228:Endothelial Growth Factors / Q000096:biosynthesis*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D008168:Lung / Q000254:growth & development* / Q000502:physiology; D008222:Lymphokines / Q000096:biosynthesis*; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis*; D017978:Receptors, Growth Factor / Q000096:biosynthesis*; D040262:Receptors, Vascular Endothelial Growth Factor; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor