Generation of reactive oxygen species contributes to the development of carbon black cytotoxicity to vascular cells

A Study on the Planarian Model Confirms the Antioxidant Properties of Tameron against X-ray- and Menadione-Induced Oxidative Stress

Ionizing radiation and radiation-related oxidative stress are two important factors responsible for the death of actively proliferating cells, thus drastically reducing the regeneration capacity of living organisms. Planarian flatworms are freshwater invertebrates that are rich in stem cells called neoblasts and, therefore, present a well-established model for studies on regeneration and the testing of novel antioxidant and radioprotective substances. In this work, we tested an antiviral and antioxidant drug Tameron (Monosodium α-Luminol or 5-amino-2,3-dihydro-1,4-phthalazinedione sodium salt) for its ability to reduce the harm of X-ray- and chemically induced oxidative stress on a planarian model. Our study has revealed the ability of Tameron to effectively protect planarians from oxidative stress while enhancing their regenerative capacity by modulating the expression of neoblast marker genes and NRF-2-controlled oxidative stress response genes.

Integrated proteomic analysis to explore the molecular regulation mechanism of IL-33 mRNA increased by black carbon in the human endothelial cell line EA.hy926

Black carbon (BC) correlates with the occurrence and progression of atherosclerosis and other cardiovascular diseases. Increasing evidence has demonstrated that BC could impair vascular endothelial cells, but the underlying mechanisms remain obscure. It is known that IL-33 exerts a significant biological role in cardiovascular disease, but little is known about the molecular regulation of IL-33 expression at present. We first found that BC significantly increased IL-33 mRNA in EA.hy926 cells in a concentration and time-dependent manner, and we conducted this study to explore its underlying mechanism. We identified that BC induced mitochondrial damage and suppressed autophagy function in EA.hy926 cells, as evidenced by elevation of the aspartate aminotransferase (GOT2), reactive oxygen species (ROS) and p62, and the reduction of mitochondrial membrane potential (ΔΨm). However, ROS cannot induce IL-33 mRNA-production in BC-exposed EA.hy926 cells. Further, experiments revealed that BC could promote IL-33 mRNA production through the PI3K/Akt/AP-1 and p38/AP-1 signaling pathways. It is concluded that BC could induce oxidative stress and suppress autophagy function in endothelial cells. This study also provided evidence that the pro-cardiovascular-diseases properties of BC may be due to its ability to stimulate the PI3K/AKT/AP-1 and p38/AP-1 pathway, further activate IL-33 and ultimately result in a local vascular inflammation.

Planarians as an In Vivo Experimental Model for the Study of New Radioprotective Substances

Ionising radiation causes the death of the most actively dividing cells, thus leading to depletion of the stem cell pool. Planarians are invertebrate flatworms that are unique in that their stem cells, called neoblasts, constantly replace old, damaged, or dying cells. Amenability to efficient RNAi treatments, the rapid development of clear phenotypes, and sensitivity to ionising radiation, combined with new genomic technologies, make planarians an outstanding tool for the discovery of potential radioprotective agents. In this work, using the well-known antioxidant N-acetylcysteine, planarians are, for the first time, shown to be an excellent model system for the fast and effective screening of novel radioprotective and radio-sensitising substances. In addition, a panel of measurable parameters that can be used for the study of radioprotective effects on this model is suggested.

Urban PM2.5 reduces angiogenic ability of endothelial cells in an alveolar-capillary co-culture lung model

Adverse health effects arising from exposure to fine particulates have become a major concern. Angiogenesis is a vital physiological process for the growth and development of cells and structures in the human body, whereby excessive or insufficient vessel growth could contribute to pathogenesis of diseases. We therefore evaluated indirect effects of carbon black (CB) and inhalable airborne particles on the angiogenic ability of unexposed Human Umbilical Vein Endothelial Cells (HUVECs) by co-culturing HUVECs with pre-exposed Small Airway Epithelial Cells (SAECs). As endothelial cells are major components of blood vessels and potential targets of fine particles, we investigated if lung epithelial cells exposed to ambient PM_2.5 surrogates could induce bystander effects on neighboring unexposed endothelial cells in an alveolar-capillary co-culture lung model. Epithelial exposure to CB at a non-toxic dose of 25 μg/mL reduced endothelial tube formation and cell adhesion in co-cultured HUVECs, and decreased expression of angiogenic genes in SAECs. Similarly, exposure of differentiated SAECs to PM_2.5 surrogates reduced cell reproductive ability, adhesion and tube formation of neighboring HUVECs. This indicates epithelial exposure to CB and urban PM_2.5 surrogates both compromised the angiogenic ability of endothelial cells through bystander effects, thereby potentially perturbing the ventilation-perfusion ratio and affecting lung function.

Evaluation of Some Biochemical Parameters and Brain Oxidative Stress in Experimental Rats Exposed Chronically to Silver Nitrate and the Protective Role of Vitamin E and Selenium

Due to undesirable hazardous interactions with biological systems, this investigation was undertaken to evaluate the effect of chronic exposure to silver on certain biochemical and some oxidative stress parameters with histopathological examination of brain, as well as the possible protective role of selenium and/or vitamin E as nutritional supplements. Thirty six male rats were divided into six groups of six each: the first group used as a control group. Group II given both vitamin E (400 mg/kg) of diet and selenium (Se) (1 mg/L) in their drinking water. Group III given silver as silver nitrate (AgNO₃) (20 mg/L). Group IV given vitamin E and AgNO₃. Group V given both AgNO₃ and selenium. Group VI given AgNO₃, vitamin E and Se. The animals were in the same exposure conditions for 3 months. According to the results which have been obtained; there was an increase in serum lactate dehydrogenase (LDH), lipase activities and cholesterol level, a decrease in serum total protein, calcium and alkaline phosphatase (ALP) activity in Ag-intoxicated rats. Moreover, the findings showed that Ag⁺ ions affected antioxidant defense system by decreasing superoxide dismutase (SOD) activity and increasing vitamin E concentration with a high level of malondialdehyde (MDA) in brain tissue. The histological examination also exhibited some nervous tissue alterations including hemorrhage and cytoplasm vacuolization. However, the co-administration of selenium and/or vitamin E ameliorated the biochemical parameters and restored the histological alterations. In conclusion, this study indicated that silver could cause harmful effects in animal body and these effects can be more toxic in high concentrations or prolonged time exposure to this metal. However, selenium and vitamin E act as powerful antioxidants which may exercise adverse effect against the toxicity of this metal.