In vitro cytogenetic toxicity of bezafibrate in human peripheral blood lymphocytes

Myelin Disruption, Neuroinflammation, and Oxidative Stress Induced by Sulfite in the Striatum of Rats Are Mitigated by the pan-PPAR agonist Bezafibrate

Sulfite predominantly accumulates in the brain of patients with isolated sulfite oxidase (ISOD) and molybdenum cofactor (MoCD) deficiencies. Patients present with severe neurological symptoms and basal ganglia alterations, the pathophysiology of which is not fully established. Therapies are ineffective. To elucidate the pathomechanisms of ISOD and MoCD, we investigated the effects of intrastriatal administration of sulfite on myelin structure, neuroinflammation, and oxidative stress in rat striatum. Sulfite administration decreased Fluoromyelin^TM and myelin basic protein staining, suggesting myelin abnormalities. Sulfite also increased the staining of NG2, a protein marker of oligodendrocyte progenitor cells. In line with this, sulfite also reduced the viability of MO3.13 cells, which express oligodendroglial markers. Furthermore, sulfite altered the expression of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1), indicating neuroinflammation and redox homeostasis disturbances. Iba1 staining, another marker of neuroinflammation, was also increased by sulfite. These data suggest that myelin changes and neuroinflammation induced by sulfite contribute to the pathophysiology of ISOD and MoCD. Notably, post-treatment with bezafibrate (BEZ), a pan-PPAR agonist, mitigated alterations in myelin markers and Iba1 staining, and IL-1β, IL-6, iNOS and HO-1 expression in the striatum. MO3.13 cell viability decrease was further prevented. Moreover, pre-treatment with BEZ also attenuated some effects. These findings show the modulation of PPAR as a potential opportunity for therapeutic intervention in these disorders.

Evaluation of in vitro and in vivo genotoxic and antigenotoxic effects of Rhus coriaria

Rhus coriaria has been important in the treatment of many diseases in traditional use. In this content, the genotoxic, antigenotoxic, and oxidative stress effects of methanol extract of R. coriaria (RCE) were investigated in this study. Two hundred fifty, 500, or 750 µg/mL concentrations of RCE were not found to have DNA damaging effect on pET22-b(+) plasmid and were unable to induce micronuclei in human lymphocytes (24 or 48 h treatment period). However, it did not inhibit the genotoxic effect of mitomycin-c (0.25 µg/mL). Cytotoxic effects of RCE were investigated using mitotic index (MI) and nuclear division index (NDI). Five hundred, 1000, and 2000 mg/kg concentrations of RCE did not induce chromosome aberrations in rat bone marrow cells for 12 or 24 h treatment period. In addition, 2000 mg/kg concentration of RCE showed an antigenotoxic effect by decreasing to genotoxic effect of 400 mg/kg urethane at 12 and 24 h treatment periods. RCE showed cytotoxic effects by significantly decreasing NDI. Moreover, RCE increased cytotoxic effect of Mitomycin C (MMC). However, RCE did not induce cytotoxicity in rat bone marrow cells. The highest concentration of RCE reduced total oxidant level in 12 h treatment. Interestingly, the lowest total oxidant level was found in rats blood treated with the lowest concentration RCE and urethane together. Thousand and 2000 mg/kg concentrations of RCE decreased total antioxidant levels of rat blood at 24 h treatment period. Our results showed that RCE possess cytotoxic effect in short-term treatments in vitro. However, it does not demonstrate genotoxic or cytotoxic effects in vivo.

New toxicogenetic insights and ranking of the selected pharmaceuticals belong to the three different classes: A toxicity estimation to confirmation approach

Tetracycline hydrochloride (TH), indomethacin (IM), and bezafibrate (BF) belong to the three different important classes of pharmaceuticals, which are well known for their toxicity and environmental concerns. However, studies are still elusive to highlight the mechanistic toxicity of these pharmaceuticals and rank them using both, the toxicity prediction and confirmation approaches. Therefore, we employed the next generation toxicity testing in 21st century (TOX21) tools and estimated the in vitro/vivo toxic endpoints of mentioned pharmaceuticals, and then confirmed them using in vitro/vivo assays. We found significant resemblance in the results obtained via both approaches, especially in terms of in vivo LC50 s and developmental toxicity that ranked IM as most toxic among the studied pharmaceuticals. However, TH appeared most toxic with the lowest estimated AC50s, the highest experimental IC50s, and DNA damages in vitro. Contrarily, IM was found as congener with priority concern to activate the Pi3k-Akt-mTOR pathway in vitro at concentrations substantially lower than that of TH and BF. Further, IM exposure at lower doses (2.79-13.97 μM) depressed the pharmaceuticals detoxification phase I (CYP450 s), phase II (UGTs, SULTs), and phase III (TPs) pathways in zebrafish, whereas, at relatively higher doses, TH (2.08-33.27 μM) and BF (55.28-884.41 μM) partially activated these pathways, which ultimately caused the developmental toxicity in the following order: IM > TH > BF. In addition, we also ranked these pharmaceuticals in terms of their particular toxicity to myogenesis, hematopoiesis, and hepatogenesis in zebrafish embryos. Our results revealed that IM significantly affected myogenesis, hematopoiesis, and hepatogenesis, while TH and BF induced prominent effects on hematopoiesis via significant downregulation of associated genetic markers, such as drl, mpx, and gata2a. Overall, our findings confirmed that IM has higher toxicity than that of TH and BF, therefore, the consumption of these pharmaceuticals should be regulated in the same manner to ensure human and environmental safety.