Experimental tracheal ligation (TL) has been shown to reverse the pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH) and to normalize gas exchange. The purpose of this study was to determine whether the TL would correct the surfactant deficiency present in the fetal rabbit model of CDH by using lamellar body count. Lamellar bodies are synthesized and secreted by the type II pneumocytes of fetal lung. The phospholipids present in these bodies constitute the major component of pulmonary surfactant. Twenty-one pregnant New Zealand rabbits underwent hysterotomy and fetal surgery on gestational day 24. Two fetuses of each pregnant rabbit were operated. In the fetus of one end of bicornuate uterus, left DH was created by excision of fetal diaphragm through open thoracotomy (DH Group). In the fetus of the other end of bicornuate uterus, left DH and TL were created (TL Group). The fetuses were delivered by Cesarean section on gestational day 31. Fourteen in control group, 12 in the DH group and 13 in TL group were born alive. En bloc excision of lungs, bronchi and trachea was done in all newborn rabbits. A five Fr catheter was inserted through trachea and repeated irrigations with 10 cc normal saline were done. The irrigated fluid was centrifuged at 280 xg for 5 minutes and the lamellar bodies were counted with the upper level fluid in platelet channel of electronic cell counter. The average lamellar body counts were 37.1 +/- 14.2 x 10(3)/microL in control group, 11.5 +/- 4.4 x 10(3)/microL in DH group, and 6.5+/- 0.9 x 10(3)/microL in TL group. Lamellar body count in DH group was lower than in control group and did not increase after TL. This study shows TL has no therapeutic effect on decreased surfactant level of CDH and the pregnant rabbit is appropriate for the animal model of CDH.
Blood Platelets ; Bronchi ; Catheters ; Cell Count ; Cesarean Section ; Diaphragm ; Electronics ; Electrons ; Female ; Fetus ; Hernia, Diaphragmatic ; Humans ; Hysterotomy ; Infant, Newborn ; Ligation ; Lung ; Models, Animal ; Organothiophosphorus Compounds ; Phospholipids ; Pneumocytes ; Pregnancy ; Pulmonary Surfactants ; Rabbits ; Thoracotomy ; Trachea ; Uterus

Background/Aims: Platelet-derived growth factor receptor alpha-positive (PDGFRα + ) cells function in the purinergic regulation of gastrointestinal motility, and purines are reportedly inhibitory neurotransmitters in the enteric nervous system. We explore the distribution and function of PDGFRα + cells related to purinergic inhibitory neurotransmission in human right and left colons. Methods: Human colonic segments were prepared with mucosa and submucosa intact, and the circular muscle tension and longitudinal muscle tension were recorded. Purinergic neurotransmitters were administered after recording the regular contractions.Immunohistochemistry was performed on the circular muscle layers. Intracellular recording was performed on the colonic muscular layer. SK3, P2RY1, and PDGFR-α mRNA expression was tested by quantitative real-time polymerase chain reaction (qPCR). Results: Adenosine triphosphate (ATP) treatment significantly decreased the frequency and area under the curve (AUC) of the segmental contraction in right and left colons. Beta-nicotinamide adenine dinucleotide (β-NAD) decreased the frequency in the right colon and the amplitude, frequency and AUC in the left colon. Apamin significantly increased frequency and AUC in the left colon, and after apamin pretreatment, ATP and β-NAD did not change segmental contractility. Through intracellular recordings, a resting membrane potential decrease occurred after ATP administration; however, the degree of decrease between the right and left colon was not different. PDGFRα +Conclusion Purines reduce right and left colon contractility similarly, and purinergic inhibitory neurotransmission can be regulated by PDGFRα+ cells in the human colon.