Intratracheal administration of endotoxin attenuates hyperoxia-induced lung injury in neonatal rats.
OBJECTIVE
This study was undertaken to determine the effects of intratracheal administration of endotoxin on hyperoxia-induced lung injury in neonatal rats.


METHODS
Newborn Sprague Dawley rat pups were divided into four experimental groups: normoxia control (NC), normoxia with endotoxin treatment (NE), hyperoxia control (HC), and hyperoxia with endotoxin treatment (HE) groups. In HC and HE, rat pups were subjected to 14 days of hyperoxia (> 95% oxygen) within 12 hours after birth. In endotoxin treated group (NE and HE), Escherichia coli endotoxin (0.5microg in 0.03mL of saline) was given intratracheally at the 1st, 3rd and 5th postnatal day. Radial alveolar count (RAC), mean linear intercept (MLI), RAC/MLI ratios, and degree of fibrosis were measured to assess the changes in lung morphology.


RESULTS
During the research period, survival rates in both HC and HE were notably reduced 7 days after endotoxin was administered, but body weight gain was considerably reduced only in HC. On day 14, significant arrest in alveolarization, as evidenced by the decrease of RAC and RAC/MLI ratio and increase of MLI as well as increased fibrosis, were noted in HC. Although slight but significant arrest in alveolarization and increased fibrosis score were observed in NE compared to NC, the hyperoxia-induced lung damage observed in HC was significantly improved in HE.


CONCLUSIONS
This study suggests that intratracheal administration of endotoxin significantly attenuated hyperoxia-induced lung injury in neonatal rats.
Shim
Jae Won
JW
Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul 135-710, Korea.
Chang
Yun Sil
YS
Park
Won Soon
WS
D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight; D004333:Drug Administration Routes; D004731:Endotoxins / Q000008:administration & dosage*; D018496:Hyperoxia / Q000150:complications*; D008171:Lung Diseases / Q000139:chemically induced* / Q000209:etiology* / Q000473:pathology; D055370:Lung Injury; D051381:Rats; D017207:Rats, Sprague-Dawley
D004731:Endotoxins