Biopharmaceutical-Type Chinese Hamster Ovary Cell Cultivation Under Static Magnetic Field Exposure: A Study of Genotoxic Effect

The lack of a sufficient research base is the reason for the ongoing discussion regarding the genotoxic effect of magnetic field (MF) exposure on mammalian cell cultures. Chinese hamster ovary (CHO) suspension-type cells, which are widely used for biopharmaceutical production, are potentially subjected to an increased MF when cultivated in bioreactors equipped with bottom-placed magnetically coupled stirring mechanisms. The main challenge for conducting research in this field remains the availability of a suitable experimental setup that generates an appropriate MF for the raised research question. In the present study, a simple and cost-effective experimental setup was developed that generated a static MF, similar to what has been modeled in large-scale bioreactors and, at the same time, was suitable for experimental cell cultivation in laboratory conditions. The measured maximum magnetic flux density to which the cells were exposed was 0.66 T. To assess the possible genotoxic effect, cells were continuously subcultivated in laboratory petri dishes for a period of 14 days, corresponding to a typical duration of a biopharmaceutical production process in a conventional fed-batch regime. The genotoxic effect was assessed using the cytokinesis-block micronucleus assay with fluorescent staining. Results showed that a 0.66-T static MF exposure had no significant long-term effect on cell viability and chromosomal damage but demonstrated a short-term effect on cell apoptosis. Significant increase in nuclear bud formation was observed. These findings may encourage other researchers in future studies investigating cellular responses to MF exposure and contribute relevant data for comparison.

Cr and Ni simultaneous phytotoxicity and mutagenicity assay

For genotoxicity study simultaneous phytotoxicity and mutagenicity assay with Vicia sativa L. var. Klára was used. For phytotoxicity the following rank orders of growth inhibition can be arranged: for roots: Ni(II) > Cr(VI) > Cr(III); for shoots: Ni(II) > Cr(VI) ≥ Cr (III). For mutagenicity assay root tips of V. sativa were used and chromosome aberrations were determined at least in 500-anatelophases. All tested metals exerted in V. sativa a significant increase of chromosomal aberration rate in applied concentrations. Maximum of aberrations invoked Cr(VI) and the rank order of aberrations fall was: Cr(VI) > Ni(II) > Cr(III). Genotoxic effects of metals were determined by analysis of micronuclei frequency in the pollen tetrads of Tradescantia plants. None of tested metal significantly stimulated micronuclei frequency and genotoxic effect was decreased in order: Cr(VI) ≥ Ni(II) > Cr(III).

Genotoxic effect of restraint and stress pheromone on somatic and germ cells of mouse males Mus musculus L.

BACKGROUND: Different stressors affect the genome integrity, but the mechanisms of such action are underexplored. MATERIALS AND METHODS: Bone marrow and testicular cells of CBA and CD-1 mouse males were used to estimate their genome integrity after stressor action by the comet assay. RESULTS: It is shown here that restraint and 2,5-dimethylpyrazine both increase damaged cell frequency in bone marrow as well as in testes of mouse males. For the first time the effect of immobilization and 2,5-dimethylpyrazine in testicular cells is demonstrated using the comet assay. Both stressors have similar effects in cells of both tissues analyzed. CONCLUSION: Mechanisms of the effects and possible role in microevolution are under discussion.

Combinatory Effects of Cerium Dioxide Nanoparticles and Acetaminophen on the Liver—A Case Study of Low-Dose Interactions in Human HuH-7 Cells

The interactions between pharmaceuticals and nanomaterials and its potentially resulting toxicological effects in living systems are only insufficiently investigated. In this study, two model compounds, acetaminophen, a pharmaceutical, and cerium dioxide, a manufactured nanomaterial, were investigated in combination and individually. Upon inhalation, cerium dioxide nanomaterials were shown to systemically translocate into other organs, such as the liver. Therefore we picked the human liver cell line HuH-7 cells as an in vitro system to investigate liver toxicity. Possible synergistic or antagonistic metabolic changes after co-exposure scenarios were investigated. Toxicological data of the water soluble tetrazolium (WST-1) assay for cell proliferation and genotoxicity assessment using the Comet assay were combined with an untargeted as well as a targeted lipidomics approach. We found an attenuated cytotoxicity and an altered metabolic profile in co-exposure experiments with cerium dioxide, indicating an interaction of both compounds at these endpoints. Single exposure against cerium dioxide showed a genotoxic effect in the Comet assay. Conversely, acetaminophen exhibited no genotoxic effect. Comet assay data do not indicate an enhancement of genotoxicity after co-exposure. The results obtained in this study highlight the advantage of investigating co-exposure scenarios, especially for bioactive substances.