Phospholipid peroxidation-driven modification of chondrogenic transcription factor mediates alkoxyl radicals-induced impairment of embryonic bone development.

Maternal stress has been associated with poor birth outcomes, including preterm birth, infant mortality, and low birth weight. Bone development disorders in the embryo as a result of maternal stress are believed to be mediated through oxidative stress damage. Various species of free radicals, such as alkoxyl radicals, can be formed through endogenous redox response or exogenous stimuli in the womb and transmitted to embryos. Yet, whether these free radicals lead to abnormal fetal bone development is unclear. Here, we demonstrate prenatal bone growth retardation and ferroptosis-related signals of chondrocytes were induced by classic alkoxyl radical generators. We also show that alkoxyl radicals lead to significant accumulation of oxidized phospholipids in chondrocytes, through the iron-mediated Fenton reaction in embryos. We further demonstrate a role for the lipid peroxidation end product, 4-HNE, which forms adducts with the pivotal chondrogenesis transcription factor SOX9, leading to its degradation, therefore dampening chondrogenesis. Our data define a critical role for phospholipid peroxidation in alkoxyl radicals-evoked abnormal chondrogenesis, and pinpoint it being a precise target for treating oxidative stress-related bone development disorders.

Comparing antioxidant capacity of purine alkaloids: a new, efficient trio for screening and discovering potential antioxidants in vitro and in vivo.

The most commonly applied strategies for the evaluation of antioxidant capacity are the chemical- or cell-based approaches. However, the results obtained from these methods might not reflect the antioxidant ability of test samples within organisms. In this study, we propose a combination of experiments, including oxygen radical absorbance capacity (ORAC), cellular antioxidant activity assay (CAA), and the chick embryo model, as an efficient trio to evaluate antioxidant capacity of food components. Taking purine alkaloids as example, results demonstrate that chemical and cellular method might misinterpret their true ability on antioxidation. In chick embryo model, caffeine and theacrine can significantly improve vessel density on chorioallantoic membrane and myocardial apoptosis. The mechanism can be involving multiple targets within the organism. We believe that the trio proposed can be widely utilized in screening massive number of antioxidant in a cost-effective way. It will also help discovering new antioxidants that are easily being omitted due to their relatively poor in vitro activities.

Glucose metabolism disorder is a risk factor in ethanol exposure induced malformation in embryonic brain.

Prenatal exposure to ethanol has been reported to cause developmental defects in the brain. During brain development, a sufficient energy source is deemed essential and glucose is regarded as the primary energy source for neurons. In this study, the impact of ethanol on embryonic malformation and cerebral glucose metabolism in developing embryo was investigated. Different doses of ethanol (0, 10, 20, 40 mg/egg) were administrated to chicken embryos after 36 h incubation. Embryonic brain weight was found significantly decreased. Moreover, we observed an obvious reduction of neurofilament expression in the central nervous system (CNS) by immunostaining assay. All the above indicated that ethanol exposure caused obvious CNS damages and resulted malformations in the developing brain. Mechanism research showed that cerebral glucose and lactic acid contents, activities of hexokinase, pyruvate kinase and lactic dehydrogenase were decreased dose dependently. Meanwhile, mRNA levels of glucose transporter 1, glucose transporter 3 and insulin-like growth factor I in the brain demonstrated a significant decrease in gene expression after ethanol exposure. These results suggested that glucose metabolism disorder is an important risk factor in ethanol exposure induced malformation in embryonic brain.

A new oxidative stress model, 2,2-azobis(2-amidinopropane) dihydrochloride induces cardiovascular damages in chicken embryo.

It is now well established that the developing embryo is very sensitive to oxidative stress, which is a contributing factor to pregnancy-related disorders. However, little is known about the effects of reactive oxygen species (ROS) on the embryonic cardiovascular system due to a lack of appropriate ROS control method in the placenta. In this study, a small molecule called 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), a free radicals generator, was used to study the effects of oxidative stress on the cardiovascular system during chick embryo development. When nine-day-old (stage HH 35) chick embryos were treated with different concentrations of AAPH inside the air chamber, it was established that the LD50 value for AAPH was 10 µmol/egg. At this concentration, AAPH was found to significantly reduce the density of blood vessel plexus that was developed in the chorioallantoic membrane (CAM) of HH 35 chick embryos. Impacts of AAPH on younger embryos were also examined and discovered that it inhibited the development of vascular plexus on yolk sac in HH 18 embryos. AAPH also dramatically repressed the development of blood islands in HH 3+ embryos. These results implied that AAPH-induced oxidative stress could impair the whole developmental processes associated with vasculogenesis and angiogenesis. Furthermore, we observed heart enlargement in the HH 40 embryo following AAPH treatment, where the left ventricle and interventricular septum were found to be thickened in a dose-dependent manner due to myocardiac cell hypertrophy. In conclusion, oxidative stress, induced by AAPH, could lead to damage of the cardiovascular system in the developing chick embryo. The current study also provided a new developmental model, as an alternative for animal and cell models, for testing small molecules and drugs that have anti-oxidative activities.