Cell death and lung cell histology in meconium aspirated newborn rabbit lung.
Meconium aspiration syndrome (MAS) is a major cause of newborn mortality and morbidity. In this study we investigated the inflammatory responses and morphological changes in the newborn lung to debris-free meconium instillation. We developed a model for studies of MAS using 2-week-old rabbit pups. Cell death was assessed by DNA staining and detection of DNA fragmentation by in situ end labeling. Cell death was seen in association with an increase of inflammatory cytokines levels, studied by ELISA. Necrotic cells were detected by staining of lavage cells with ethidium bromide and 4',6'-diamino-2'-phenylidon. Meconium instillation resulted selectively in loss of airway and alveolar epithelial cells followed by cell death, which increased with time. Necrotic cells looked smaller and damaged with maximal counts at 24 h after instillation.


CONCLUSIONS
Meconium instillation into lungs caused massive cell death, possibly by apoptosis, and necrosis that may have been activated by the inflammatory cytokine production.
Zagariya
A
A
Department of Pediatrics, Michael Reese Hospital, Chicago, IL 60616, USA.
Bhat
R
R
Uhal
B
B
Navale
S
S
Freidine
M
M
Vidyasagar
D
D
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D016923:Cell Death / Q000502:physiology; D016207:Cytokines / Q000032:analysis / Q000276:immunology*; D053938:DNA Fragmentation; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D004848:Epithelium / Q000473:pathology; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000378:metabolism / Q000473:pathology*; D008471:Meconium Aspiration Syndrome / Q000276:immunology* / Q000378:metabolism / Q000503:physiopathology; D009336:Necrosis; D011817:Rabbits; D013997:Time Factors
D016207:Cytokines