The expression of PDGF, its receptors and capillary morphometry in the developing lung: quantitative studies.

: The aim of the present study was the evaluation of the expression levels of PDGF-A and B, and PDGFR-alpha, andchanges of capillary cross-sectional areas during terminal vascular network formation in the developing lung. Pathogen-free fetuses and newborns used for rats were used. Lungs were processed for frozen section immunohistochemical staining and parallel tissue specimens were prepared for transmission electron microscopy. The expression levels of PDGF-A and B, and PDGFR-alpha were obtained using quantitative image analysis. Additionally. the morphometry of capillary cross-sectional area was performed. We found that the expression levels of the studied antigens fluctuated, and the highest values were found in21-day old fetuses (p < 0.0001). Although there were no significant differences of the area of "a single" capillary, the area of the endothelium decreased significantly in perinatal period (p <0.0001). We conclude that the statistically significant changes of the studied antigens' expression as well as the of capillary cross-sectional area occur in the perinatal period,