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Since biological applications and toxicity of graphene-based materials are structure dependent, studying their interactions with the biological systems is very timely and important. We studied short-term (1, 24, and 48 h) effects of ultrapure (GO) and Mn2+-contaminated (GOS) graphene oxide on normal human dermal fibroblasts (NHDF) and adenocarcinomic human alveolar basal epithelial cells (A549) using selected oxidative stress markers and cytokines: glutathione reductase (GR) and catalase (CAT) activity, total antioxidative capacity (TAC), and malondialdehyde (MDA) concentration, levels of vascular endothelial growing factor (VEGF), tumor necrosis factor-alpha (TNF-α), platelet-derived growth factor-BB (PDGF-BB), and eotaxin. GOS induced higher levels of oxidative stress, measured with CAT activity, TAC, and MDA concentration than GO in both cell lines when compared to control cells. GR activity decreased in time in NHDF cells but increased in A549 cells. The levels of cytokines were related to the exposure time and graphene oxide type in both analyzed cell lines and their levels comparably increased over time. We observed higher TNF-α levels in NHDF and higher levels of VEGF and eotaxin in the A549 cell line. Both types of cells showed similar susceptibility to GO and GOS. We concluded that the short-time exposure to GOS induced the stronger response of oxidative stress markers without collapsing the antioxidative systems of analysed cells. Increased levels of inflammatory cytokines after GO and GOS exposure were similar both in NHDF and A549 cells.

Obesity and high-fat diet (HF) are prevalent causes of oxidative stress (OS). Duodenal-jejunal omega switch (DJOS) is a bariatric procedure used for body mass reduction, extensively tested in animal models. We studied the long-term impact of bariatric surgery and an HF diet on the oxidative stress markers in erythrocytes and heart muscles of rats. We analyzed superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx) activity and malondialdehyde (MDA) concentration in DJOS or SHAM (control) operated rats fed with different dietary protocols (control diet (CD) and high-fat diet (HF)), before and after the surgery (CD/CD, HF/HF, CD/HF, and HF/CD). We observed higher erythrocytes CAT, GST and GPx activity in DJOS-operated (vs. SHAM) rats fed with an HF/HF diet. For DJOS-operated rats, erythrocytes CAT and GPx activity and MDA concentration were significantly lower in CD/CD group. We observed increased heart muscle GR activity in SHAM-operated rats (vs. DJOS bariatric surgery) fed with an HF/HF diet. Change from HF to CD diet increased heart muscle GPx activity after DJOS bariatric surgery. Heart muscle SOD activity was lower in HF/HF and CD/CD groups after DJOS bariatric surgery (vs. SHAM). DJOS surgery significantly reduced heart muscle MDA concentration in HF/HF and HF/CD groups (vs. SHAM). We conclude that the selected dietary patterns had a stronger impact on oxidative stress markers in erythrocytes and heart muscle than DJOS bariatric surgery.