Metabolic activation of drugs in mutagenicity tests in vitro

1980 ◽  
Vol 46 (1-2) ◽  
pp. 181-193 ◽  
Author(s):  
M. B. Roberfroid
Keyword(s):  
Metabolic Activation ◽  
Mutagenicity Tests

scholarly journals Geigerin-induced cytotoxicity in a murine myoblast cell line (C2C12)

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Christo J. Botha ◽  
Sarah J. Clift ◽  
Gezina C.H. Ferreira ◽  
Mxolisi G. Masango
Keyword(s):  
Flow Cytometry ◽  
Cell Line ◽  
Ethical Issues ◽  
Sesquiterpene Lactones ◽  
Annexin V ◽  
Metabolic Activation ◽  
Suitable Model ◽  
Myoblast Cell Line ◽  
Myoblast Cell

Geigeria poisoning in sheep, locally known as ‘vermeersiekte’, is an economically important plant poisoning in southern Africa. The toxic principles contained by the toxic plants are believed to be several sesquiterpene lactones, such as geigerin, vermeeric acid and vermeerin, which cause striated muscle lesions in small stock. Because of ethical issues surrounding the use of live animals in toxicity studies, there is currently a dire need to establish an in vitro model that can be used to replace traditional animal experimentation. The objective of this study was to determine the cytotoxicity of geigerin in a murine myoblast cell line (C2C12) using methyl-thiazol-tetrazolium (MTT) and lactate dehydrogenase (LDH) assays, annexin V and propidium iodide (PI) flow cytometry and transmission electron microscopy (TEM). Mouse myoblasts were exposed to 2.0 mM, 2.5 mM and 5.0 mM geigerin for 24, 48 and 72 h. A concentration-dependent cytotoxic response was observed. Apoptosis was detected by means of annexin V flow cytometry during the first 24 h and apoptotic bodies were also visible on TEM. According to the LDH and PI flow cytometry results, myoblast cell membranes were not injured. We concluded that the murine myoblast cell line (C2C12) is a suitable model for future studies planned to evaluate the cytotoxicity of other and combinations of sesquiterpene lactones, with and without metabolic activation, implicated in ‘vermeersiekte’ and to elucidate the subcellular effects of these myotoxins on cultured myoblasts.

High Content Analysis of an In Vitro Model for Metabolic Toxicity

2014 ◽  
Vol 19 (10) ◽  
pp. 1402-1408 ◽  
Author(s):  
Stephanie D. Cole ◽  
Janna S. Madren-Whalley ◽  
Albert P. Li ◽  
Russell Dorsey ◽  
Harry Salem
Keyword(s):  
Content Analysis ◽  
High Throughput ◽  
Metabolic Activation ◽  
Hepatic Metabolism ◽  
Cell Types ◽  
Multiple Organ ◽  
Compound Libraries ◽  
High Content Analysis ◽  
Calcein Am

In vitro models that accurately and rapidly assess hepatotoxicity and the effects of hepatic metabolism on nonliver cell types are needed by the U.S. Department of Defense and the pharmaceutical industry to screen compound libraries. Here, we report the first use of high content analysis on the Integrated Discrete Multiple Organ Co-Culture (IdMOC) system, a high-throughput method for such studies. We cultured 3T3-L1 cells in the presence and absence of primary human hepatocytes, and exposed the cultures to 4-aminophenol and cyclophosphamide, model toxicants that are respectively detoxified and activated by the liver. Following staining with calcein-AM, ethidium homodimer-1, and Hoechst 33342, high content analysis of the cultures revealed four cytotoxic endpoints: fluorescence intensities of calcein-AM and ethidium homodimer-1, nuclear area, and cell density. Using these endpoints, we observed that the cytotoxicity of 4-aminophenol in 3T3-L1 cells in co-culture was less than that observed for 3T3-L1 monocultures, consistent with the known detoxification of 4-aminophenol by hepatocytes. Conversely, cyclophosphamide cytotoxicity for 3T3-L1 cells was enhanced by co-culturing with hepatocytes, consistent with the known metabolic activation of this toxicant. The use of IdMOC plates combined with high content analysis is therefore a multi-endpoint, high-throughput capability for measuring the effects of metabolism on toxicity.

scholarly journals In vitro versus in vivo metabolic activation of mutagens.

1973 ◽  
Vol 6 ◽  
pp. 71-82 ◽  
Author(s):  
H V Malling ◽  
C N Frantz
Keyword(s):  
Metabolic Activation

scholarly journals In vitro genotoxicity evaluation and metabolic study of residual glutaraldehyde in animal-derived biomaterials

2020 ◽  
Vol 7 (6) ◽  
pp. 619-625
Author(s):  
Jianfeng Shi ◽  
Huan Lian ◽  
Yuanli Huang ◽  
Danmei Zhao ◽  
Han Wang ◽  
...  
Keyword(s):  
Metabolic Activation ◽  
Chemical Toxicity ◽  
Major Health ◽  
Mouse Lymphoma Assay ◽  
Metabolic Mechanism ◽  
Mutagenic Effects ◽  
Mouse Lymphoma ◽  
General Balance ◽  
In Vitro Genotoxicity

Abstract Glutaraldehyde (GA) is an important additive that is mainly used in animal-derived biomaterials to improve their mechanical and antimicrobial capacities. However, GA chemical toxicity and the metabolic mechanism remain relatively unknown. Therefore, residual GA has always been a major health risk consideration for animal-derived medical devices. In this study, extracts of three bio-patches were tested via the GA determination test and mouse lymphoma assay (MLA). The results showed that dissolved GA was a potential mutagen, which could induce significant cytotoxic and mutagenic effects in mouse lymphoma cells. These toxic reactions were relieved by the S9 metabolic activation (MA) system. Furthermore, we confirmed that GA concentration decreased and glutaric acid was generated during the catalytic process. We revealed GA could be oxidized via cytochrome P450 which was the main metabolic factor of S9. We found that even though GA was possibly responsible for positive reactions of animal-derived biomaterials’ biocompatibility evaluation, it may not represent the real situation occurring in human bodies, owing to the presence of various detoxification mechanisms including the S9 system. Overall, in order to achieve a general balance between risk management and practical application, rational decisions based on comprehensive analyses must be considered.

scholarly journals Microbial enzymes induce colitis by reactivating triclosan in the mouse gastrointestinal tract

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Jianan Zhang ◽  
Morgan E. Walker ◽  
Katherine Z. Sanidad ◽  
Hongna Zhang ◽  
Yanshan Liang ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Metabolic Activation ◽  
Consumer Products ◽  
Environmental Chemicals ◽  
Intestinal Microbes ◽  
Targeted Inhibition

AbstractEmerging research supports that triclosan (TCS), an antimicrobial agent found in thousands of consumer products, exacerbates colitis and colitis-associated colorectal tumorigenesis in animal models. While the intestinal toxicities of TCS require the presence of gut microbiota, the molecular mechanisms involved have not been defined. Here we show that intestinal commensal microbes mediate metabolic activation of TCS in the colon and drive its gut toxicology. Using a range of in vitro, ex vivo, and in vivo approaches, we identify specific microbial β-glucuronidase (GUS) enzymes involved and pinpoint molecular motifs required to metabolically activate TCS in the gut. Finally, we show that targeted inhibition of bacterial GUS enzymes abolishes the colitis-promoting effects of TCS, supporting an essential role of specific microbial proteins in TCS toxicity. Together, our results define a mechanism by which intestinal microbes contribute to the metabolic activation and gut toxicity of TCS, and highlight the importance of considering the contributions of the gut microbiota in evaluating the toxic potential of environmental chemicals.

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