title: Infusing sodium bicarbonate suppresses hydrogen peroxide accumulation and superoxide dismutase activity in hypoxic-reoxygenated newborn piglets.
abstract: BACKGROUND
  The effectiveness of sodium bicarbonate (SB) has recently been questioned although it is often used to correct metabolic acidosis of neonates. The aim of the present study was to examine its effect on hemodynamic changes and hydrogen peroxide (H(2)O(2)) generation in the resuscitation of hypoxic newborn animals with severe acidosis.
  
  
  METHODS
  Newborn piglets were block-randomized into a sham-operated control group without hypoxia (n = 6) and two hypoxia-reoxygenation groups (2 h normocapnic alveolar hypoxia followed by 4 h room-air reoxygenation, n = 8/group). At 10 min after reoxygenation, piglets were given either i.v. SB (2 mEq/kg), or saline (hypoxia-reoxygenation controls) in a blinded, randomized fashion. Hemodynamic data and blood gas were collected at specific time points and cerebral cortical H(2)O(2) production was continuously monitored throughout experimental period. Plasma superoxide dismutase and catalase and brain tissue glutathione, superoxide dismutase, catalase, nitrotyrosine and lactate levels were assayed.
  
  
  RESULTS
  Two hours of normocapnic alveolar hypoxia caused cardiogenic shock with metabolic acidosis (PH: 6.99 ± 0.07, HCO(3)(-): 8.5 ± 1.6 mmol/L). Upon resuscitation, systemic hemodynamics immediately recovered and then gradually deteriorated with normalization of acid-base imbalance over 4 h of reoxygenation. SB administration significantly enhanced the recovery of both pH and HCO(3-) recovery within the first hour of reoxygenation but did not cause any significant effect in the acid-base at 4 h of reoxygenation and the temporal hemodynamic changes. SB administration significantly suppressed the increase in H(2)O(2) accumulation in the brain with inhibition of superoxide dismutase, but not catalase, activity during hypoxia-reoxygenation as compared to those of saline-treated controls.
  
  
  CONCLUSIONS
  Despite enhancing the normalization of acid-base imbalance, SB administration during resuscitation did not provide any beneficial effects on hemodynamic recovery in asphyxiated newborn piglets. SB treatment also reduced the H(2)O(2) accumulation in the cerebral cortex without significant effects on oxidative stress markers presumably by suppressing superoxide dismutase but not catalase activity.
authors: Department of Neonatology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China.
authors: Jiang-Qin
authors: JQ
authors: Liu
authors: Namdar
authors: N
authors: Manouchehri
authors: Tze-Fun
authors: TF
authors: Lee
authors: Mingzhu
authors: M
authors: Yao
authors: David L
authors: DL
authors: Bigam
authors: Po-Yin
authors: PY
authors: Cheung
mesh_terms: D000136:Acid-Base Equilibrium / Q000187:drug effects; D000138:Acidosis / Q000188:drug therapy* / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001784:Blood Gas Analysis; D002374:Catalase / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D005978:Glutathione / Q000378:metabolism; D006439:Hemodynamics; D006861:Hydrogen Peroxide / Q000378:metabolism*; D000860:Hypoxia; D007262:Infusions, Intravenous; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism; D012151:Resuscitation; D017693:Sodium Bicarbonate / Q000008:administration & dosage* / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism*; D013552:Swine; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D019344:Lactic Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D017693:Sodium Bicarbonate; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione; D010100:Oxygen