Vannucchi C I, Kishi D, Regazzi F M, Silva Lcg, Veiga Gal, Angrimani Dsr, Lucio C F, Nichi M
Department of Animal Reproduction, School of Veterinary Medicine and Animal Sciences, University of São Paulo, São Paulo, Brazil.
Reprod Domest Anim. 2015 Apr;50(2):240-246. doi: 10.1111/rda.12476. Epub 2015 Jan 21.
During the initiation of neonatal pulmonary respiration, there is an exponential increase in reactive oxygen species that must be scavenged by antioxidant defences. However, neonate and preterm newborns are known to possess immature antioxidant mechanisms to neutralize these toxic effects. The purposes of this study were to compare the development of antioxidant system between preterm and term canine neonates and to evaluate the magnitude of acid-base balance during the initial 4 h of life. A prospective study was conducted involving 18 neonatal puppies assigned to Term Group (63 days of gestation; n = 5), Preterm-57 Group (57 days of gestation; n = 8) and Preterm-55 Group (55 days of gestation; n = 5). Neonates were physically examined through Apgar score and venous haemogasometry within 5 min, 2 and 4 h after birth. No difference on amniotic fluid and serum superoxide dismutase (SOD), glutathione peroxidase (GPx) and the marker of oxidative stress (thiobarbituric acid reactive substances; TBARS) was verified. Irrespective of prematurity, all neonates presented low vitality, hypothermia, acidosis, hypoxaemia and hypercapnia at birth. However, term puppies clinically evolved more rapidly than preterm newborns. During the course of the study, premature neonates presented more severe complications, such as prolonged hypoxaemia and even death. In conclusion, premature puppies have no signs of immature enzymatic mechanisms for controlling oxidative stress, although SOD and GPx may participate in achieving acid-base balance. Aside from initial unremarkable symptoms, premature puppies should be carefully followed up, as they are at high risk of succumbing to odds of prematurity.
在新生儿肺呼吸启动过程中，活性氧呈指数增加，必须由抗氧化防御系统清除。然而，已知新生儿和早产儿的抗氧化机制不成熟，无法中和这些毒性作用。本研究的目的是比较早产和足月犬新生儿抗氧化系统的发育情况，并评估出生后最初4小时内酸碱平衡的程度。进行了一项前瞻性研究，涉及18只新生幼犬，分为足月组（妊娠63天；n = 5）、早产-57组（妊娠57天；n = 8）和早产-55组（妊娠55天；n = 5）。在出生后5分钟、2小时和4小时内，通过阿氏评分和静脉血气分析对新生儿进行体格检查。未发现羊水和血清中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPx）以及氧化应激标志物（硫代巴比妥酸反应性物质；TBARS）存在差异。无论早产与否，所有新生儿出生时均表现出活力低下、体温过低、酸中毒、低氧血症和高碳酸血症。然而，足月幼犬的临床进展比早产儿更快。在研究过程中，早产新生儿出现了更严重的并发症，如长时间低氧血症甚至死亡。总之，早产幼犬没有控制氧化应激的酶机制不成熟的迹象，尽管SOD和GPx可能参与实现酸碱平衡。除了最初不明显的症状外，早产幼犬应仔细随访，因为它们面临早产风险而死亡的可能性很高。
