Ga Won Jeon

Erythropoietin Attenuates Brain Injury, Subventricular Zone Expansion, and Sensorimotor Deficits in Hypoxic-Ischemic Neonatal Rats

The aim of this study was to investigate the effect of erythropoietin (EPO) on histological brain injury, subventricular zone (SVZ) expansion, and sensorimotor function deficits induced by hypoxia-ischemia (HI) in newborn rat pups. Seven-day-old male rat pups were divided into six groups: normoxia control, normoxia EPO, hypoxia control, hypoxia EPO, HI control, and HI EPO group. Sham surgery or HI was performed in all animals. HI was induced by ligation of the right common carotid artery followed by 90 min of hypoxia with 8% oxygen. Recombinant human EPO 3 U/g or saline was administered intraperitoneally, immediately, at 24- and 48-hr after insult. At two weeks after insult, animals were challenged with cylinder-rearing test for evaluating forelimb asymmetry to determine sensorimotor function. All animals were then sacrificed for volumetric analysis of the cerebral hemispheres and the SVZ. The saline-treated HI rats showed marked asymmetry by preferential use of the non-impaired, ipsilateral paw in the cylinder-rearing test. Volumetric analysis of brains revealed significantly decreased preserved ipsilateral hemispheric volume and increased ipsilateral SVZ volume compared with the sham-operated animals. Treatment of EPO significantly improved forelimb asymmetry and preserved ipsilateral hemispheric volume along with decreased expansion of ipsilateral SVZ following HI compared to the saline-treated HI rats. These results support the use of EPO as a candidate drug for treatment of neonatal hypoxic-ischemic brain damage.

Outcome Following Surgical Closure of Patent Ductus Arteriosus in Very Low Birth Weight Infants in Neonatal Intensive Care Unit

Purpose The aims of this study were to determine the factors affecting the outcome of patent ductus arteriosus ligation in very low birth weight infants (VLBWI) and demonstrate the safety of PDA ligation in VLBWI performed in the neonatal intensive care unit (NICU). Materials and Methods From October 1994 to July 2006, medical records of 94 VLBWI weighing < 1,500 g who underwent PDA ligation in the NICU of Samsung Medical Center were reviewed retrospectively. Factors affecting the final outcome of PDA ligation were evaluated by dividing the infants into 3 groups according to mortality and major morbidities as follows: mortality group (Mo), major morbidity group (Mb), and no major morbidity group (NM). Results In the Mo group, birth weight was significantly lower and the preoperative mean FiO2 and mean dopamine dose were significantly higher than those in the other 2 groups. There was no significant difference in gestational age, incidence of RDS, number of courses of indomethacin, surgery-related factors, including weight and age at surgery, perioperative vital signs, and complications after surgery between the 3 groups. During surgery in the NICU, there were no significant hemodynamic instability or serious acute complications. Conclusion The factors affecting the outcome of surgery in VLBWI are not the factors related to surgery but the preoperative conditions related to the underlying prematurity. PDA ligation of VLBWI performed in the NICU is safe without serious complications.

Antenatal betamethasone attenuates intrauterine infection-aggravated hyperoxia-induced lung injury in neonatal rats

Background:Intrauterine infection can exacerbate postnatal hyperoxic lung injury. We hypothesized that antenatal betamethasone treatment attenuates hyperoxic lung injury aggravated by intrauterine infection in neonatal rats.Methods:Newborn Sprague-Dawley rats were divided into eight experimental groups according to (i) whether rats were exposed to normoxia (N) or hyperoxia (H, 85% oxygen) from postnatal day (P)1 to P14, (ii) whether antenatal betamethasone (0.2 mg/dose) or vehicle was administered to pregnant rats at gestation days (E)19 and E20, and (iii) whether intrauterine infection was induced or not antenatally. Intrauterine infection was induced by intracervical inoculation of Escherichia coli into pregnant rats on E19. We measured cytokine levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β in P1 rat lungs and performed morphometric analyses and assessed inflammatory responses in lung tissue and bronchoalveolar lavage (BAL) at P14 by terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick end labeling (TUNEL) staining and measurement of myeloperoxidase activity, collagen, and cytokine levels.Results:Cytokine levels in P1 rat lungs were increased by intrauterine infection, and these increases were attenuated by antenatal betamethasone. Hyperoxic lung injuries, indicated by morphometric changes and an inflammatory response in the lung and BAL fluid, were aggravated by intrauterine infection at P14. This aggravation was significantly attenuated by antenatal betamethasone.Conclusion:Antenatal betamethasone attenuated aggravated hyperoxic lung injuries induced by intrauterine infection in neonatal rats via its anti-inflammatory actions.