J Korean Soc Neonatol.
2010 May;17(1):44-52.
Neonatal Rat Necrotizing Enterocolitis Model Adopting Oral Endotoxin and Hypoxia Exhibits Increased Apoptosis through Caspase-3 Activation
- Affiliations
-
- 1Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
- 2Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
- 3Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea. kimek@snu.ac.kr
Abstract
- PURPOSE
The aim of this study was to develop a model for necrotizing enterocolitis (NEC) in the neonatal rat using endotoxin and hypoxia, a plausible insult in a neonatal intensive care and to investigate the role of apoptosis as the underlying mechanism.
METHODS
Newborn rats were given oral endotoxin and intermittent 8% hypoxia+/-caspase inhibitor. The intestinal histology was evaluated using hematoxylin-eosin staining. Apoptosis was analyzed with TUNEL staining and by measuring the caspase 3 activity in the intestinal lysates. IEC-6 cells were assessed for apoptosis and the expression of Bax, Bcl-2, Fas and FasL was measured after treatment with endotoxin and hypoxia.
RESULTS
Oral endotoxin (5 mg/kg) and exposure to 8% hypoxia of 60-min duration twice induced human NEC-like lesions in the rat intestine. Intestinal tissue revealed increased apoptosis and caspase-3 activity. After caspase inhibitor treatment, the grades of both apoptosis and NEC were significantly reduced. IEC-6 cells exhibited increased apoptosis and caspase 3 activity after endotoxin and hypoxia treatment and significantly increased Bax/Bcl-2 ratio compared to control cells.
CONCLUSION
This neonatal rat model of NEC which was induced by oral endotoxin and intermittent hypoxia showed increased apoptosis of intestinal epithelial cells that was mediated by caspase 3 activation. Our model has a advantage in the study of NEC because the use of much more clinically plausible insults may provide a suitable model for the investigation of its pathophysiology and therapeutic trials.
