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.

ß-lactamase genes transmission influenced by tetracycline, sulfonamide and ß-lactams antibiotics contamination in the on-site farm soil.

The prevalence of antibiotic resistance genes (ARGs), which have been identified as emerging environmental pollutants that pose a considerable risk to human health is widespread. The formation and transmission of ARGs are mainly associated with the antibiotic stress in an environment. And the abundance of ARGs also influenced by other categories antibiotics. The geographic information system was used to visualize the relative abundance of 28 types of ARGs and concentration of 18 types of antibiotics. The concentration of tetracycline antibiotics (TCs) and sulfonamide antibiotics (SAs) decreased gradually with increasing soil depth, while that of ß-lactams (ß-Ls) showed an increasing trend. The results revealed that TCs accounted for the largest proportion of all antibiotics. Furthermore, the abundance of ß-lactam ARGs (ß-RGs) increased with TCs and ß-Ls increased. The abundance of tetracycline ARGs (TRGs) remained relatively stable with increasing concentrations of all antibiotics, while that of sulfonamide ARGs (SRGs) showed a decreasing trend. Although the abundance of ß-RGs significantly increased with increasing levels of TCs and ß-Ls. However, ß-RGs were not significantly correlated with ß-Ls, but with TCs. This study provided visual and comprehensive insights into the correlation between the distribution of typical antibiotics and ARGs and analyzed the synergy or antagonism between different antibiotics and ARGs. It is significant for soil remediation to reduce the likelihood of ARGs entering into and spreading in the human food chain via milk and beef consumption.

Inhibitory regulation of purple sweet potato polysaccharide on the hepatotoxicity of tri-(2,3-dibromopropyl) isocyanate.

Tri-(2,3-dibromopropyl) isocyanate (TBC), a new emerged persistent organic pollutant, is widely used in fields of flame retardant, textile, rubber and plastic with strong hepatotoxicity. Purple Sweet Potato Polysaccharide (PSPP) has antioxidant and hepatoprotective effects. This study aims to answer the scientific question whether PSPP has a protective effect on TBC induced liver injury. The effect of PSPP on the apoptosis of HepG2 cells was detected by MTT assay, the morphological changes were observed by morphological observation, and the apoptosis rate was determined by flow cytometry. The apoptotic genes were detected by qPCR assay, the relevant protein express was detected by western blot. The correlation between proteins and genes in the apoptosis pathway of HepG2 cells was calculated. To further reveal the apoptosis mechanism of TBC hepatotoxicity in vivo, 19 target genes and 14 apoptotic related proteins of inhibiting apoptosis via death receptor and mitochondria were discussed, all the above results proved that PSPP had protective effect on liver injury induced by TBC. This study not only provided a scientific basis for clarifying the mechanism of TBC hepatotoxicity and the protective effect of PSPP, but also generated the new point and method in terms of the prevention in advance and early intervention of diseases caused by environmental pollution.

The Interactions Between Antibiotic Resistance Genes and Heavy Metal Pollution Under Co-Selective Pressure Influenced the Bio-Enzyme Activity.

The spread of antibiotic resistance genes (ARGs) has brought potential risks to public health. However, the interactions between heavy metals and ARGs, as well as their potential effect on bio-enzyme activity under the pressure of co-selectivity in soil still remain poorly understood. In this work, the distribution characteristics and the co-selective relationship of 28 ARGs and eight heavy metals in soil in a dairy farm were visualized via the geographic information system (GIS) technique. Eight kinds of heavy metals were detected by an atomic fluorescence spectrometer and atomic absorption spectrophotometer, which were further evaluated via the single factor pollution index value. The GIS analysis showed that arsenic (As) was the key element responsible for soil pollution, which was found to be positively related to soil depths. The top three comprehensive scores of ARGs ranked the orders of sul2 > tetX > blaTEM, indicating the high potential of risk caused by these genes in the soil environment. In addition, the functional predications performed with the 16 SrDNA sequencing data based on the KEGG database indicated that the sulfonamides in soil involved multiple pathways, especially the metabolism, transport and catabolism, and membrane transport processes. This suggested that most bio-enzymes were found to be expressed in low activities in different pathways. Significant correlations were observed between the heavy metals and ARGs (p < 0.05), particularly between the ARGs and As, Cu, Ni, Pb, and Zn (p < 0.01). This study offers deep insights into the potential interactions between heavy metals and ARGs in soil and provides guidance for the fabrication of enzyme-based smart materials for soil remediation in dairy farms.