Pulmonary surfactant migrates into the alveolar capillaries of newborn rats: an immunoelectron microscopic study.
The goal of the present study was to elucidate the migration of surfactant-like material into the alveolar capillaries of newborn rats. The lungs of experimental animals were studied by ultrastructural techniques-standard electron microscopy as well as immunoelectron microscopy-using antibodies against synthetic polypeptide complementary to the noncollagenous part of surfactant protein A (SP-A). Antibodies exhibited specific reaction with native rat SP-A in Western blot and immunohistochemical analysis. Surfactant was observed in the alveolar space, type II pneumocytes, macrophages, type I pneumocytes, endothelial cells, the extracellular space of the alveolar septa and in the alveolar capillaries. Lamellar structures observed in all elements of the blood-air barrier as well as in the alveolar capillaries were stained positively with anti-SP-A antibodies. Transport of the pulmonary surfactant into the circulatory system was observed more frequently during the first 6-8 h of extrauterine life of newborn rats, although it was also seen in the blood vessels till 48 h after delivery. The results of our investigation suggest that clearance of surfactant via the circulatory system plays an important role in the early postnatal period.
Wasowicz
M
M
First Department of Pathology, Oita Medical University, Japan.
Kashima
K
K
Yokoyama
S
S
Nakayama
I
I
D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport; D002196:Capillaries / Q000378:metabolism*; D008168:Lung / Q000098:blood supply*; D016253:Microscopy, Immunoelectron; D011663:Pulmonary Surfactants / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D011663:Pulmonary Surfactants