In situ localization of tris(2,3-dibromopropyl) isocyanurate in mouse organs by MALDI-IMS with auxiliary matrix strategy

Developing CHCA/PPD as a novel matrix for enhanced matrix-assisted laser desorption/ionization-mass spectrometry imaging for analysis of antibiotics in grass carp tissues

Antibiotics have important medical value, but they need to be monitored when used as veterinary drugs. We report α-cyano-4-hydroxycinnamic acid/p-phenylenediamine (CHCA/PPD) hybrid as a novel matrix for enhanced matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) in situ the spatial distribution of antibiotic drugs in grass carp tissues.

METHOD

We have used MALDI-TOF-MSI in positive ion mode for the analysis of quinolones and sulfonamides in grass carps. A novel CHCA/PPD matrix was prepared and applied using a simple method to improve the analysis.

RESULTS

Compared with the traditional matrix, CHCA/PPD significantly improved the detection intensity of quinolones and sulfonamides with better sensitivity (17.20%-94.30%) and reproducibility. For demonstration, this novel matrix was successfully applied to visualize enrofloxacin (ENR) in grass carp tissues, with the entire abundance differences clearly observed based on MALDI-MSI. The concentration levels in different tissues were determined, with a calibration curve of 10-2000 μg/ml (R²  > 0.993).

CONCLUSION

This study was the first to introduce CHCA/PPD as a novel matrix, and the classical acid-base mixing was used to improve the ionization effect of the traditional matrix CHCA in MALDI. Based on CHCA/PPD, MALDI-MSI detected ENR in different grass carp tissues for the first time and realized the spatial distribution and concentration detection.

Comprehensive review of the impact of tris(2,3-dibromopropyl) isocyanurate (TBC or TDBP-TAZTO) on living organisms and the environment

Tris(2,3-dibromopropyl) isocyanurate (TBC or TDBP-TAZTO) belongs to the group of brominated flame retardants (BFRs). The production of this compound is increasing due to the growing demand and wide application in electrical, electronic, musical instrument, and automotive component industries. The properties of TBC, e.g., the high octanol-air partition coefficient (Koa), high octanol-water partition coefficient (Kow), and high bioconcentration factor (BCF), indicate a possibility of its spread in aquatic and terrestrial ecosystems and bioaccumulation in living organisms. The presence of TBC has been confirmed in soil, sediments, river water, and such materials as microplastic, curtains, and e-waste devices. The compound has potential to bioaccumulate in the food chain of living organisms. TBC has been demonstrated to exert a harmful effect mainly on the nervous and endocrine systems, lungs, and liver. The possible mechanism of toxicity of the compound in the nervous system is based on the generation of oxidative stress by TBC leading to apoptosis of neuronal cells, while mitochondrial damage is considered to be responsible for changes in the respiratory organ. Moreover, the potential of mussels and earthworms to be bioindicators of TBC has been proven. Therefore, the literature review is focused on TBC properties and analysis of the identification and impact of the compound on the environment, living organisms, and human cell lines. Given the many toxic effects of TBC highlighted in the literature, there is a need for more profound research on the safety of TBC and methods for identification and degradation of this compound.

In vivo and in vitro study on hepatotoxicity of Tris-(2, 3-dibromopropyl) isocyanurate exposure via mitochondrial and death receptor pathway

Tri-(2,3-dibromopropyl) isocyanate (TBC), a newly brominated flame retardant, is widely used in the synthesis of flame retardant materials with characteristics of persistent organic pollutants. To obtain environmental exposure risks of TBC, Wistar rats and HepG2 cell were used for in vivo and in vitro studies on the toxicity of TBC and relevant ecotoxicological mechanisms of apoptosis. 80 Wistar rats were randomly selected and divided into four exposure groups (0, 0.313, 0.625, 1.250) g/(kg·bw) TBC, half male and half female, with oral administration for 28 days. Wistar rats exhibited appetite loss, weight loss, and dull hair with increasing period of TBC exposure. The pathological examinations revealed the most severe damage of liver and the ratio of liver/body weight of 35.497 × 10^-3 for high-dosed group (1.250 g/kg·bw) was higher than that of 32.792 × 10^-3 for control group in female rats with identical trend in male rats. The above indicators was fairly consistent with the serum test results which further confirmed the liver to be the target organ. The exposure dosages of HepG2 cell were (0, 12.5, 25, 50) μg/mL, individually. The HepG2 cells exposed to TBC for 72 h displayed hazy cell contour and decreased density of cell growth. And there was an inhibition detected by MTT assay, where the maximum inhibition rate was 19.93% under the dose of 50 μg/mL TBC. Apoptosis rate detected by flow cytometry which was demonstrated to be positively correlated to exposure dosage of TBC. The apoptosis rates of the low, medium and high dose groups of TBC exposure were (1.082 ± 0.109) %, (3.017 ± 0.09) % and (6.813 ± 0.233) %, individually. Targeted genes and corresponding protein expressions that triggering apoptosis both in vivo and in vitro were significantly altered. Overall, this work discloses the impacts of TBC exposure on hepatotoxicity, which provides new insights for chemical risk assessments of accelerate cell apoptosis via mitochondrial and death receptor pathway.