Genotoxic evaluation of five Angiotesin II receptor blockers: In vivo and in vitro micronucleus assay

Abstract Risk management of in vitro aneugens for topically applied compounds is not clearly defined because there is no validated methodology to accurately measure compound concentration in proliferating stratum basale keratinocytes of the skin. Here, we experimentally tested several known aneugens in the EpiDerm reconstructed human skin in vitro micronucleus assay and compared the results to flow cytometric mechanistic biomarkers (phospho-H3; MPM2, DNA content). We then evaluated similar biomarkers (Ki-67, nuclear area) using immunohistochemistry in skin sections of minipigs following topical exposure the potent aneugens, colchicine, and hesperadin. Data from the EpiDerm model showed positive micronucleus responses for all aneugens tested following topical or direct media dosing with similar sensitivity when adjusted for applied dose. Quantitative benchmark dose-response analysis exhibited increases in the mitotic index biomarkers phospho-H3 and MPM2 for tubulin binders and polyploidy for aurora kinase inhibitors are at least as sensitive as the micronucleus endpoint. By comparison, the aneugens tested did not induce histopathological changes, increases in Ki-67 immunolabeling or nuclear area in skin sections from the in vivo minipig study at doses in significant excess of those eliciting a response in vitro. Results indicate the EpiDerm in vitro micronucleus assay is suitable for the hazard identification of aneugens. The lack of response in the minipig studies indicates that the barrier function of the minipig skin, which is comparable to human skin, protects from the effects of aneugens in vivo. These results provide a basis for conducting additional studies in the future to further refine this understanding.

Download Full-text

In vitro and in vivo evaluation of clastogenicity of second-line antitubercular drug loaded PLGA nanoparticles

Human & Experimental Toxicology ◽

10.1177/0960327120979345 ◽

2020 ◽

pp. 096032712097934

Author(s):

Avaneesh Kumar Pandey ◽

Rajendra Kumar ◽

Nusrat Shafiq ◽

Ritika Kondel ◽

Shanky Garg ◽

...

Keyword(s):

Micronucleus Assay ◽

Plga Nanoparticles ◽

Second Line ◽

Cho Cell ◽

In Vivo Evaluation ◽

Antitubercular Drugs ◽

Significant Difference ◽

In Vitro Micronucleus Assay

Sustained release nanoformulations of second line antitubercular drugs levofloxacin and ethionamide had shown promise in pharmacokinetics and acute and sub-acute toxicity studies. The present study evaluated the clastogenicity potential of the nanoformulations of these antitubercular agents. Clastogenicity was evaluated by (a) in vitro micronucleus assay (b) in vivo micronucleus assay in Swiss albino mice and (c) sister chromatid exchange (SCE) in CHO cell lines. Ethionamide and levofloxacin loaded nanoparticles were 312 ± 64 nm and 245 ± 24 nm in size respectively and drug encapsulation was 35.2 ± 3.1% w/w and 45.6 ± 9.4% w/w, respectively. The frequency of MN-NCE/1000 NCE and MN-PCE/1000 PCE were significantly reduced in mice treated with ethionamide nanoparticle (3.5 ± 0.9, 13.8 ± 16.68) and levofloxacin nanoparticles (5.6 ± 2.7, 16.7 ± 12.7) compared to the mice treated with free ethionamide (11.5 ± 4.1, p = 0.23 and 45.19 ± 19.21, p = 0.38) and free levofloxacin (14.7 ± 1.88, p < 0.0001 and 54.6 ± 18.1, p = 0.0017), respectively. For in vitro, micronucleus assay frequencies of micronuclei per thousand bi-nucleated cells (MN-BN/1000 BN) was 188.3 ± 20.20 and 148 ± 20.42 for ethionamide and levofloxacin nanoparticles as compared to 232.6 ± 16.04 (p = 0.52) and 175 ± 5.56 (p = 0.45) for free ethionamide and levofloxacin, respectively. The average number of SCE per cell for nanoformulation of ethionamide were not different from that of free drug (4.9 ± 0.51 vs 4.1 ± 0.55, p = 0.86). The SCE per cells were not significant difference for nanoformulation of levofloxacin (2.33 ± 1.36 vs 5.46 ± 0.25, p = 0.88). In vitro and in vivo assays have shown relatively less clastogenic potential of equivalent dose of ethionamide nanoparticles as compared to the conventional formulation.

Download Full-text

Satureja subspicata and S. horvatii Extracts Induce Overexpression of the BCl-2 Family of Anti-apoptotic Genes and Reduce Micronuclei Frequency in Mice

Natural Product Communications ◽

10.1177/1934578x1801300617 ◽

2018 ◽

Vol 13 (6) ◽

pp. 1934578X1801300

Author(s):

Jasmina Čakar ◽

Naida Kadrić Lojo ◽

Anja Haverić ◽

Maida Hadžić ◽

Lejla Lasić ◽

...

Keyword(s):

Human Lymphocyte ◽

Micronucleus Assay ◽

Balkan Peninsula ◽

Lymphocyte Culture ◽

Cytotoxic Activities ◽

Cytotoxic Effects ◽

Apoptotic Genes ◽

Apoptotic Activity

Satureja subspicata and S. horvatii are endemic species of the Balkan Peninsula and often used in traditional medicine in Bosnia and Herzegovina to treat different health conditions. We aimed to analyze the unevaluated apoptotic, genotoxic and cytotoxic effects of two Satureja species, as well as their content of phenolics that are mainly responsible for the plant's biological activity. Apoptotic and geno/cytotoxic activities of S. subspicata and S. horvatii were investigated in vitro in human lymphocyte culture and in vivo in mice. The content of the main phenolics in plant extracts was determined by ultra-high pressure liquid chromatography-MS-MS (UHPLC–MS/MS). Genotoxic and cytotoxic activities of Satureja extracts were evaluated in vitro by applying a cytokinesis-block micronucleus cytome assay in human lymphocyte culture and in vivo applying a mice reticulocytes micronucleus assay. SALSA RT-MLPA R011-C1 apoptosis assay was used for measuring the relative expression of 44 genes associated with the regulation of the apoptotic pathways in human lymphocyte cultures treated with different concentrations of two Satureja extracts. The first analysis of phenolic compounds in S. horvatii and S. subspicata determined by an UHPLC-MS/MS method revealed high levels of rosmarinic and caffeic acids. Minor genotoxic potential was determined in relation to the tested concentrations while no cytostatic and cytotoxic effects were revealed in vitro. However, when applied in concentrations of 200 mg/kg per os, aqueous extracts of two Satureja species significantly decreased frequency of reticulocytes micronuclei in treated mice against controls. Extracts of S. subspicata and S. horvatii in concentrations of 0.2 mg/mL, regardless of solvent used, downregulated pro-apoptotic and upregulated anti-apoptotic genes, showing anti-apoptotic activity. Our results indicate that the registered anti-genotoxic and anti-apoptotic activity is most likely related to the high level of phenolic acids (particularly rosmarinic and caffeic) in the tested extracts.

Download Full-text