Generally, oxidative stress is considered to be an imbalance between the production and the ability to scavenge the reactive oxygen species. Reactive oxygen species can interact with various molecules (i.e. lipid, protein, and nucleic acid) and, then, cause oxidative damage. In recent decades, numerous well-designed investigation have indicated that oxidative stress is involved in the development of many miscellaneous diseases, including diabetes, cancer, aging, inflammation, cardiovascular disease, neurological disease, Parkinson’s disease, obesity, and acute respiratory distress syndrome.

Human and mammalian birth is characterized by a sudden transition process from maternal mediated respiration in uterus to autonomous pulmonary respiration outside the uterus. In other words, infants would encounter an abrupt environment change from an intrauterine hypoxia to an extrauterine hyperoxia. In response to the changes of extrauterine conditions, newborns generate large amount of reactive oxygen species, then might result in oxidative stress.

Using newborn piglet as vivo experimental model, researchers from the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) spent several months to elucidate the birth oxidative stress and the development of antioxidant system in new born piglets.

The researchers found that piglets suffered serious lipid, protein, and nucleic acid oxidative damages at first week after birth. Meanwhile, through antioxidant enzymes analysis, the results showed that the activities of antioxidant enzymes exhibited at very lower level during the first week in newborn piglets. “So it makes sense that the poor antioxidant system contributes tremendously to the oxidative injury caused by reactive oxygen species during the birth period,” said by Dr. YIN Yulong from ISA. “And with the development of antioxidant system, the reactive oxygen species significantly decreased by the upregulated antioxidant enzymes. Therefore, the results from oxidant injury products exhibited a downward trend, while the antioxidant enzymes appeared in an upward trend.”

The researchers also found that reactive oxygen species and oxidative injury can negatively activate several signal pathways (i.e. Nrf2/Keap1 signal axis system) to mediate antioxidant related genes expression and release of antioxidant enzymes. As Dr. Yin said: “with the polish of antioxidant system, the oxidative balance gradually recovered at day 7 after birth. According to some experts, supplementation with antioxidants would excise a beneficial function in newborn infants, however, we also speculate that there might be no necessity to add some antioxidant after 1 week basing our result.”

The research was supported by the National Natural Science Foundation of China (No. 31272463), Hunan Provincial Natural Science Foundation of China (No. 12JJ2014), and Chinese Academy of Sciences Visiting Professorship for Senior International Scientists Grant No. 2011T2S15.

The main findings of this research have been published on Free radical research Vol. 47:1027-1035 (doi: 10.3109/10715762.2013.848277). Details can be found at http://www.ncbi.nlm.nih.gov/pubmed/24074241