Topical bromfenac in VEGF-driven maculopathies: topical review and meta-analysis.

BACKGROUND: Topical non-steroidal anti-inflammatory drugs have the potential to reduce treatment burden and improve outcomes of anti-VEGF therapy for a number of retinal disorders, including neovascular age-related macular degeneration, diabetic macular edema, and retinal vein occlusions. In this review, we focused on the advantages of topical bromfenac as an adjunct to intravitreal anti-VEGF therapy in VEGF-driven maculopathies. METHODS: Cochrane Library, PubMed, and EMBASE were systematically reviewed to identify the relevant studies of neovascular age-related macular degeneration, diabetic macular edema, macular edema associated with retinal vein occlusion, myopic choroidal neovascularization, and radiation maculopathy which reported changes in central retinal thickness, visual acuity, and the number of anti-VEGF injections needed when anti-VEGF therapy was combined with topical bromfenac. RESULTS: In total, ten studies evaluating bromfenac as an adjunct to anti-VEGF therapy were identified. Five studies were included in meta-analysis of the number of injections and five studies were included in the analysis of changes in central retinal thickness. A statistically significantly lower number of intravitreal injections (p = 0.005) was required when bromfenac was used as an adjunct to anti-VEGF therapy compared to anti-VEGF monotherapy with pro re nata regimen. At the same time, eyes receiving bromfenac as an adjunct to anti-VEGF therapy demonstrated non-inferior outcomes in central retinal thickness (p = 0.07). Except for one study which reported better visual outcomes with combined treatment, no difference in visual acuity or clinically significant adverse effects were reported. CONCLUSIONS: This literature review and meta-analysis showed that topical bromfenac can be considered as a safe adjunct to anti-VEGF therapy with a potential to reduce the treatment burden with anti-VEGF drugs requiring frequent injections without compromising improvement of central retinal thickness or visual acuity.

Life-time exposure to decabromodiphenyl ethane (DBDPE) caused transgenerational epigenetic alterations of thyroid endocrine system in zebrafish.

Because of its ubiquitous occurrence in the environment, decabromodiphenyl ethane (DBDPE), a novel brominated flame retardant, has been widely concerned. However, its transgenerational thyroid disrupting potential and intricate mechanism are barely explored. Therefore, zebrafish embryos were exposed to environmentally relevant concentrations of DBDPE (0, 0.1, 1 and 10 nM) until sexual maturity. The results indicated that life-time exposure to DBDPE caused anxiety-like behavior in unexposed offspring. Furthermore, the changing of thyroid hormones as well as transcriptional and DNA methylation level in the promoter region of related genes were evaluated. The thyroid disruptions observed in F1 larvae were primarily attributed to excessive transfer of thyroid hormone from F0 adults to F1 eggs. Conversely, the disruptions in F2 larvae were likely due to inherited epigenetic changes, specifically hypomethylation of crh and hypermethylation of ugt1ab, passed down from the F1 generation. Additionally, our results revealed sex-specific responses of the hypothalamic-pituitary-thyroid (HPT) axis in adult zebrafish. Furthermore, thyroid disruptions observed in unexposed offspring were more likely inherited from their mothers. The current results prompted our in-depth understanding of the multi- and transgenerational toxicity by DBDPE, and also highlighted the need to consider their adverse effects on persistent and inheritable epigenetic changes in future research on emerging pollutants.

Molecular Interaction Fields Describing Halogen Bond Formable Areas on Protein Surfaces.

Molecular interaction fields (MIFs) are three-dimensional interaction maps that describe the intermolecular interactions expected to be formed around target molecules. In this paper, a method for the fast computation of MIFs using the approximation functions of quantum mechanics-level MIFs of small model molecules is proposed. MIF functions of N-methylacetamide with chlorobenzene, bromobenzene, and iodobenzene probes were precisely approximated and used to calculate the MIFs on protein surfaces. This method appropriately reproduced halogen-bond-formable areas around the ligand-binding sites of proteins, where halogen bond formation was suggested in a previous study.

Mechanistic and kinetic insights into the thermal degradation of decabromodiphenyl ethane.

Decabromodiphenyl ethane (DBDPE), as one of the important new brominated flame retardants, is widely utilized in a variety of plastic products. However, the pyrolysis mechanism of DBDPE remains uncertain. In this article, the evolution behavior of the main products during the thermal decomposition of DBDPE is investigated using density functional theory at the theoretical level of M06-2X/6-311++G(2df,p)//M06-2X/6-311+G(d). The results show that the initial reaction starts with the cleavage of the ethane bridge bond, with an absorbed heat value of 298 kJ/mol, and the cleavage of the Caromatic-Br bond generates bromine radical, which is the main competitive reaction, with a heat absorption of 317 kJ/mol. The initial degradation of DBDPE generates a large number of pentabromobenzyl radicals and bromine radicals, which facilitate the secondary pyrolysis of DBDPE to a certain extent, resulting in the formation of possible products such as pentabromobenzyl bromide, pentabromobenzene, pentabromotoluene, hexabromobenzene, pentabromostyrene, and hydrogen bromide. In the pyrolysis system of DBDPE with hydrogen radicals, the reactions are classified into two types: extraction reaction and addition reaction. It can be known that the addition reaction plays a dominant role in the degradation process, with a branching ratio of 89.8% at 1600 K. The degradation of DBDPE with hydrogen radicals is mainly characterized by debromination, and the main products are hydrogen bromide, low-brominated diphenyl ethanes, brominated phenanthrenes, and brominated monoaromatic compounds. In addition, the lowest reaction energy barrier (18 kJ/mol) is required for the addition of hydrogen radical to the ipso-C site of DBDPE. DBDPE is dangerous for the environment and humans since its fate includes bioaccumulation, biomagnification, and toxicity via hormones and endocrine disruptors.

Polybrominated diphenyl ethers and their alternatives in soil cores from a typical flame-retardant production park: Vertical distribution and potential influencing factors.

With the prohibition on the production and use of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and organophosphate flame retardants (OPFRs) have emerged as their alternatives. However, the vertical transport and associated influencing factors of these chemicals into soil are not clearly understood. To clarify the vertical distribution of the pollutants and related influencing factors, surface soil and soil core samples were collected at a depth in the range of 0.10-5.00 m in a typical 20-year-old flame-retardant production park and surrounding area. PBDEs and DBDPE show a clear point source distribution around the production park with their central concentrations up to 2.88 × 104 and 8.46 × 104 ng/g, respectively. OPFRs are mainly found in residential areas. The production conversion of PBDEs to DBDPE has obvious environmental characteristics. The vertical distribution revealed that most of the pollutants have penetrated into the soil 5.00 m or even deeper. The median concentrations of deca-BDE and DBDPE reached 50.9 and 9.85 × 103 ng/g, respectively, even at a depth of 5.00 m. Soil organic matter plays a crucial role in determining the vertical distribution, while soil clay particles have a greater impact on the high molecular weight and/or highly brominated compounds.

Co-exposure of decabromodiphenyl ethane and polystyrene nanoplastics damages grass carp (Ctenopharyngodon idella) hepatocytes: Focus on the role of oxidative stress, ferroptosis, and inflammatory reaction.

Decabromodiphenyl ethane (DBDPE) and polystyrene nanoplastics (PS-NPs) are emerging pollutants that seriously threaten the ecological safety of the aquatic environment. However, the hepatotoxicity effect of their combined exposure on aquatic organisms has not been reported to date. In, this study, the effects of single or co-exposure of DBDPE and PS-NPs on grass carp hepatocytes were explored and biomarkers related to oxidative stress, ferroptosis, and inflammatory cytokines were evaluated. The results show that both single and co-exposure to DBDPE and PS-NPs caused oxidative stress. Oxidative stress was induced by increasing the contents of pro-oxidation factors (ROS, MDA, and LPO), inhibiting the activity of antioxidant enzymes (CAT, GPX, T-SOD, GSH, and T-AOC), and downregulating the mRNA expressions of antioxidant genes (GPX1, GSTO1, SOD1, and CAT); the effects of combined exposure were stronger overall. Both single and co-exposure to DBDPE and PS-NPs also elevated Fe2+ content, promoted the expressions of TFR1, STEAP3, and NCOA4, and inhibited the expressions of FTH1, SLC7A11, GCLC, GSS, and GPX4; these effects resulted in iron overload-induced ferroptosis, where co-exposure had stronger adverse effects on ferroptosis-related biomarkers than single exposure. Moreover, single or co-exposure enhanced inflammatory cytokine levels, as evidenced by increased mRNA expressions of IL-6, IL-12, IL-17, IL-18, IL-1ß, TNF-α, IFN-γ, and MPO. Co-exposure exhibited higher expression of pro-inflammatory cytokines compared to single exposure. Interestingly, the ferroptosis inhibitor ferrostatin-1 intervention diminished the above changes. In brief, the results suggest that DBDPE and PS-NPs trigger elevated levels of inflammatory cytokines in grass crap hepatocytes. This elevation is achieved via oxidative stress and iron overload-mediated ferroptosis, where cytotoxicity was stronger under co-exposure compared to single exposure. Overall, the findings contribute to elucidating the potential hepatotoxicity mechanisms in aquatic organisms caused by co-exposure to DBDPE and PS-NPs.

Effect of Bromfenac on Reducing Neuroinflammation in an Ischemia-Reperfusion Glaucoma Model.

In the context of glaucoma, intraocular pressure (IOP) and age are recognized as the primary factors contributing to its onset and progression. However, significant reductions in IOP fail to completely halt its advancement. An emerging body of literature highlights the role of neuroinflammation in glaucoma. This study aimed to explore Bromfenac's anti-inflammatory properties in mitigating neuroinflammation associated with glaucoma using an ischemia-reperfusion (IR) glaucoma model. Bromfenac's impact on microglia and astrocytes under pressure was assessed via Western blotting and an enzyme-linked immunosorbent assay. Immunohistochemical staining was used to evaluate glial activation and changes in inflammatory marker expression in the IR model. Bromfenac led to the downregulation of inflammatory markers, which were elevated in the conditions of elevated pressure, and necroptosis markers were downregulated in astrocytes. In the IR model, elevated levels of GFAP and Iba-1 indicated glial activation. Following Bromfenac administration, levels of iNOS, COX-2, and PGE2-R were reduced, suggesting a decrease in neuroinflammation. Furthermore, Bromfenac administration in the IR model resulted in the improved survival of retinal ganglion cells (RGCs) and preservation of retinal function, as demonstrated by immunohistochemical staining and electroretinography. In summary, Bromfenac proved effective in diminishing neuroinflammation and resulted in enhanced RGC survival.

Co-exposure of decabromodiphenyl ethane and cadmium increases toxicity to earthworms: Enrichment, oxidative stress, damage and molecular binding mechanisms.

The increase of electronic waste worldwide has resulted in the exacerbation of combined decabromodiphenyl ethane (DBDPE) and cadmium (Cd) pollution in soil, posing a serious threat to the safety of soil organisms. However, whether combined exposure increases toxicity remains unclear. Therefore, this study primarily investigated the toxic effects of DBDPE and Cd on earthworms at the individual, tissue, and cellular levels under single and combined exposure. The results showed that the combined exposure significantly increased the enrichment of Cd in earthworms by 50.32-90.42 %. The toxicity to earthworms increased with co-exposure, primarily resulting in enhanced oxidative stress, inhibition of growth and reproduction, intensified intestinal and epidermal damage, and amplified coelomocyte apoptosis. PLS-PM analysis revealed a significant and direct relationship between the accumulation of target pollutants in earthworms and oxidative stress, damage, as well as growth and reproduction of earthworms. Furthermore, IBR analysis indicated that SOD and POD were sensitive biomarkers in earthworms. Molecular docking elucidated that DBDPE and Cd induced oxidative stress responses in earthworms through the alteration of the conformation of the two enzymes. This study enhances understanding of the mechanisms behind the toxicity of combined pollution and provides important insights for assessing e-waste contaminated soils.

Effect of topical bromfenac on intraretinal cystoid lesion in simultaneous cataract and idiopathic epiretinal membrane surgery.

PURPOSE: To investigate the effect of topical nonsteroidal anti-inflammatory drugs (NSAIDs,) bromfenac on the intraretinal cystic lesions (IRC) when performing simultaneous cataract and idiopathic epiretinal membrane (iERM) surgery. METHODS: This study included patients with iERM who had been followed up for 6 months after vitrectomy, membrane removal, and concurrent cataract surgery. Eyes were treated with topical bromfenac or not. The baseline fluorescein angiography (FA) was obtained to assess the microvascular leakage (ML). Structural changes of macula, including IRC and central macular thickness (CMT) were assessed using optical coherence tomography (OCT). The main outcome measures were changes in IRCs and best-corrected visual acuity (BCVA) regarding FA findings. RESULTS: One hundred eighteen eyes were included. IRC and ML were observed in 51 eyes (43.2%) and 63 eyes (53.4%), respectively. The IRC did not show any association with the ML. Of total, 29 eyes (24.6%) were treated with topical bromfenac (Group A). Compared to Group B, topical bromfenac did not show beneficial effects in aspect of preventions for the newly developed IRC and treatment for pre-existed IRC. Whether the ML existed or not, topical bromfenac did not show any different effect on the changes in BCVA and IRC. CONCLUSION: When performing simultaneous cataract and ERM surgery, topical NSAIDs, bromfenac did not show beneficial effects on the preventions and treatment of IRC in both eyes with and without the ML.

COMPARISON OF THE EFFECTS OF EIGHT DIFFERENT TOPICAL NONSTEROIDAL ANTI-INFLAMMATORY DRUGS ON REDUCING INTRAVITREAL INJECTION-INDUCED PAIN.

PURPOSE: To compare topical nonsteroidal anti-inflammatory drug (NSAID) efficacy on intravitreal injection-induced pain reduction and determine the most efficient topical NSAID. METHODS: This randomized-controlled study included 662 eyes of 662 patients. Based on the types of NSAID administered before intravitreal injection, eight subgroups were formed. In the control group, a sterile saline solution was applied instead of NSAIDs. The visual analog scale was used to assess pain scores after intravitreal injection. The visual analog scale scores were noted immediately and 6 hours following injection (sixth hour). RESULTS: Nepafenac 0.3%, nepafenac 0.1%, and bromfenac 0.09% had the lowest scores, immediately after and after 6 hours, with no significant differences. Diclofenac and ketorolac had higher visual analog scale scores than the first trio but lower scores than the control group. Flurbiprofen, pranoprofen, and indomethacin did not significantly affect immediate pain; however, at the sixth hour, the visual analog scale scores were significantly reduced. CONCLUSION: Nepafenac 0.3%, nepafenac 0.1%, and bromfenac 0.09% were the most effective NSAIDs for pain reduction. Although some NSAIDs did not have a significant effect on immediate pain, they all provided significant benefits at the sixth hour.

Role of microsomal metabolism in bromfenac-induced cytotoxicity.

This study delves into the intricate mechanisms underlying drug-induced liver injury (DILI) with a specific focus on bromfenac, the withdrawn nonsteroidal anti-inflammatory drug. DILI is a pervasive concern in drug development, prompting market withdrawals and posing significant challenges to healthcare. Despite the withdrawal of bromfenac due to DILI, the exact role of its microsomal metabolism in inducing hepatotoxicity remains unclear. Herein, employing HepG2 cells with human liver microsomes and UDP-glucuronic acid (UDPGA), our investigation revealed a substantial increase in bromfenac-induced cytotoxicity in the presence of UDPGA, pointing to the significance of UDP-glucuronosyltransferase (UGT)-dependent metabolism in augmenting toxicity. Notably, among the recombinant UGTs examined, UGT2B7 emerged as a pivotal enzyme in the metabolic activation of bromfenac. Metabolite identification studies disclosed the formation of reactive intermediates, with bromfenac indolinone (lactam) identified as a potential mediator of hepatotoxic effects. Moreover, in cytotoxicity experiments, the toxicity of bromfenac lactam exhibited a 34-fold increase, relative to bromfenac. The toxicity of bromfenac lactam was mitigated by nicotinamide adenine dinucleotide phosphate-dependent metabolism. This finding underscores the role of UGT-dependent metabolism in generating reactive metabolites that contribute to the observed hepatotoxicity associated with bromfenac. Understanding these metabolic pathways and the involvement of specific enzymes, such as UGT2B7, provides crucial insights into the mechanisms of bromfenac-induced liver injury. In conclusion, this research sheds light on the metabolic intricacies leading to cytotoxicity induced by bromfenac, especially emphasizing the role of UGT-dependent metabolism and the formation of reactive intermediates like bromfenac lactam. These findings offer insight into the mechanistic basis of DILI and emphasize the importance of understanding metabolism-mediated toxicity.

Transcriptome-based approach to identify mechanisms underlying locomotor abnormality induced by decabromodiphenyl ethane in zebrafish larvae.

The brominated flame retardant decabromodiphenyl ethane (DBDPE) has been extensively used following restrictions on BDE-209 and thus, been frequently detected in aquatic environment. However, information on impact of DBDPE on fish development and the potential mechanisms remains scarce. In present study, developing zebrafish were employed as a study model. Embryos were exposed until 5 d to DBDPE at concentrations of 0, 3, 30, and 300 µg/L, following which the impact on larval development was investigated. DBDPE bioaccumulation and locomotor hyperactivity were observed in developing zebrafish exposed to DBDPE. Transcriptome and bioinformatics analyses indicated that pathways associated with cardiac muscle contraction and retinol metabolism were notably affected. The mechanisms of DBDPE to induce locomotor abnormality were further investigated by analyzing levels of retinol and retinol metabolites, eye and heart histology, heart rates, and ATPase activity. Our results indicate that locomotor hyperactivity observed in larvae exposed to DBDPE results from abnormal heartbeat, which in turn is attributable to inhibition of Na+/K+-ATPase activity. Furthermore, DBDPE did not change larval eye histology and contents of retinoid (retinol, retinal, and retinoic acid). This study provides insight into the mechanisms underlying DBDPE-induced developmental toxicity and highlights the need for addressing the environmental risks for aquatic organisms.

Evidence for Adverse Effects on Liver Development and Regeneration in Zebrafish by Decabromodiphenyl Ethane.

Decabromodiphenyl ethane (DBDPE), a ubiquitous emerging pollutant, could be enriched in the liver of organisms, but its effects and mechanisms on liver development and regeneration remain largely unknown. In the present study, we first investigated the adverse effects on liver development and found decreased area and intensity of fluorescence in transgenic zebrafish larvae exposed to DBDPE; further results in wild-type zebrafish larvae revealed a possible mechanism involving disturbed MAPK/Fox O signaling pathways and cell cycle arrest as indicated by decreased transcription of growth arrest and DNA-damage-inducible beta a (gadd45ba). Subsequently, an obstructed recovery process of liver tissue after partial hepatectomy was characterized by the changing profiles of ventral lobe-to-intestine ratio in transgenic female adults upon DBDPE exposure; further results confirmed the adverse effects on liver regeneration by the alterations of the hepatic somatic index and proliferating cell nuclear antigen expression in wild-type female adults and also pointed out a potential role of a disturbed signaling pathway involving cell cycles and glycerolipid metabolism. Our results not only provided novel evidence for the hepatotoxicity and underlying mechanism of DBDPE but also were indicative of subsequent ecological and health risk assessment.

Hydroxylated transformation products obtained after UV irradiation of the current-use brominated flame retardants hexabromobenzene, pentabromotoluene, and pentabromoethylbenzene.

Hexabromobenzene (HBB), pentabromotoluene (PBT), and pentabromoethylbenzene (PBEB) are current-use brominated flame retardants (cuBFRs) which have been repeatedly detected in environmental samples. Since information on hydroxylated transformation products (OH-TPs) was scarcely available, the three polybrominated compounds were UV irradiated for 10 min in benzotrifluoride. Fractionation on silica gel enabled the separate collection and identification of OH-TPs. For more insights, aliquots of the separated OH-TPs were UV irradiated for another 50 min (60 min total UV irradiation time). The present investigation of polar UV irradiation products of HBB, PBT, and PBEB was successful in each case. Altogether, eight bromophenols were detected in the case of HBB (three Br3-, four Br4-, and one Br5-isomer), and nine OH-TPs were observed in the case of PBT/PBEB (six Br3- and three Br4-congeners). In either case, Br➔OH exchange was more relevant than H➔OH exchange. Also, such exchange was most relevant in meta- and ortho-positions. As a further point, and in agreement with other studies, the transformation rate decreased with decreasing degree of bromination. UV irradiation of HBB additionally resulted in the formation of tri- and tetrabrominated dihydroxylated compounds (brominated diphenols) that were subsequently identified. These dihydroxylated transformation products were found to be more stable than OH-TPs.

Toxicity of decabromodiphenyl ethane on lettuce: Evaluation through growth, oxidative defense, microstructure, and metabolism.

Decabromodiphenyl ethane (DBDPE) as the most widely used novel brominated flame retardants (NBFRs), has become a ubiquitous emerging pollutant in the environment. However, its toxic effects on vegetable growth during agricultural production have not been reported. In this study, we investigated the response mechanisms of hydroponic lettuce to DBDPE accumulation, antioxidant stress, cell structure damage, and metabolic pathways after exposure to DBDPE. The concentration of DBDPE in the root of lettuce was significantly higher than that in the aboveground part. DBDPE induced oxidative stress on lettuce, which stimulated the defense of the antioxidative system of lettuce cells, and the cell structure produced slight plasma-wall separation. In terms of metabolism, metabolic pathway disorders were caused, which are mainly manifested as inhibiting amino acid biosynthesis and metabolism-related pathways, interfering with the biosyntheses of amino acids, organic acids, fatty acids, carbohydrates, and other substances, and ultimately manifested as decreased total chlorophyll content and root activity. In turn, metabolic regulation alleviated antioxidant stress. The mechanisms of the antioxidative reaction of lettuce to DBDPE were elucidated by IBR, PLS-PM analysis, and molecular docking. Our results provide a theoretical basis and research necessity for the evaluation of emerging pollutants in agricultural production and the safety of vegetables.

Evaluation and Mechanistic Study of Transgenerational Neurotoxicity in Zebrafish upon Life Cycle Exposure to Decabromodiphenyl Ethane (DBDPE).

The novel brominated flame retardant decabromodiphenyl ethane (DBDPE) has become a ubiquitous emerging pollutant in the environment, which may evoke imperceptible effects in humans or wild animals. Hence in this study, zebrafish embryos were exposed to DBDPE (0, 0.1, 1, and 10 nM) until sexual maturity (F0), and F1 and F2 generations were cultured without further exposure to study the multi- and transgenerational toxicity and underlying mechanism. The growth showed sex-different changing profiles across three generations, and the social behavior confirmed transgenerational neurotoxicity in adult zebrafish upon life cycle exposure to DBDPE. Furthermore, maternal transfer of DBDPE was not detected, whereas parental transfer of neurotransmitters to zygotes was specifically disturbed in F1 and F2 offspring. A lack of changes in the F1 generation and opposite changing trends in the F0 and F2 generations were observed in a series of indicators for DNA damage, DNA methylation, and gene transcription. Taken together, life cycle exposure to DBDPE at environmentally relevant concentrations could induce transgenerational neurotoxicity in zebrafish. Our findings also highlighted potential impacts on wild gregarious fish, which would face higher risks from predators.

Mitochondrial Dysfunction Was Involved in Decabromodiphenyl Ethane-Induced Glucolipid Metabolism Disorders and Neurotoxicity in Zebrafish Larvae.

Decabromodiphenyl ethane (DBDPE), a novel brominated flame retardant, is becoming increasingly prevalent in environmental and biota samples. While DBDPE has been shown to cause various biological adverse effects, the molecular mechanism behind these effects is still unclear. In this research, zebrafish embryos were exposed to DBDPE (50-400 µg/L) until 120 h post fertilization (hpf). The results confirmed the neurotoxicity by increased average swimming speed, interfered neurotransmitter contents, and transcription of neurodevelopment-related genes in zebrafish larvae. Metabolomics analysis revealed changes of metabolites primarily involved in glycolipid metabolism, oxidative phosphorylation, and oxidative stress, which were validated through the alterations of multiple biomarkers at various levels. We further evaluated the mitochondrial performance upon DBDPE exposure and found inhibited mitochondrial oxidative respiration accompanied by decreased mitochondrial respiratory chain complex activities, mitochondrial membrane potential, and ATP contents. However, addition of nicotinamide riboside could effectively restore DBDPE-induced mitochondrial impairments and resultant neurotoxicity, oxidative stress as well as glycolipid metabolism in zebrafish larvae. Taken together, our data suggest that mitochondrial dysfunction was involved in DBDPE-induced toxicity, providing novel insight into the toxic mechanisms of DBDPE as well as other emerging pollutants.

Involvement of Bmal1 and Clock in Bromobenzene Metabolite-Induced Diurnal Renal Toxicity.

Circadian rhythms are endogenous oscillators that regulate 24 h behavioral and physiological processes. Our previous investigation demonstrated that bromobenzene metabolite (4-bromocatechol: 4-BrCA) exhibited chronotoxicity (i.e., the nephrotoxicity induced by 4-BrCA was observed during the dark phase, while not observed at light phase in mice). However, the molecular mechanism is still unknown. The aim of the present study is to investigate the cellular molecule(s) involved in the 4-BrCA-induced nephrotoxicity using mouse renal cortex tubular cell lines (MuRTE61 cells). We found that 4-BrCA showed dose dependent (0.01-1 mM) cell proliferation defect in MuRTE61 cells. By treating with 0.03 mM 4-BrCA, we demonstrated that major clock genes (Bmal1, Clock, Cry1, Cry2, Per1, and Per2) were significantly downregulated. Interestingly, the expression levels of two genes, Bmal1 and Clock, continued to decrease after 3 h of treatment with 4-BrCA, while Cry1, Per1, and Per2 were unchanged until 24 h of treatment. Moreover, BMAL1 and CLOCK levels are higher at light phase. We speculated that BMAL1 and CLOCK might function defensively against 4-BrCA-induced nephrotoxicity since the expression levels of Bmal1 and Clock were rapidly decreased. Finally, overexpression of Bmal1 and Clock restored 4-BrCA-induced cell proliferation defect in MuRTE61 cells. Taken together, our results suggest that Bmal1 and Clock have protective roles against 4-BrCA-induced nephrotoxicity.

Influence of organic cosolvents on hexabromobenzene degradation in solution by montmorillonite-templated subnanoscale zero-valent iron.

Organic cosolvents are commonly used to increase the dissolution of poorly water-soluble organic pollutants into aqueous solutions during environmental remediation. In this study, the influences of five organic cosolvents on hexabromobenzene (HBB) degradation catalyzed by one typical reactive material montmorillonite-templated subnanoscale zero-valent iron (CZVI) were investigated. The results demonstrated that all cosolvents promoted HBB degradation but the degree of promotion was different for different cosolvents, which was associated with inconsistent solvent viscosities, dielectric constant properties, and the extent of interactions between cosolvents with CZVI. Meanwhile, HBB degradation was highly dependent on the volume ratio of cosolvent to water, which increased in the range of 10%-25% but persistently decreased in the range of more than 25%. This might be due to the fact that the cosolvents increased HBB dissolution at low concentrations but reduced the protons supplied by water and the contact between HBB with CZVI at high concentrations. In addition, the freshly-prepared CZVI had higher reactivity to HBB than the freeze-dried CZVI in all water-cosolvent solutions, probably because freeze-drying reduced the interlayer space of CZVI and thus the contact probability between HBB and active reaction sites. Finally, the CZVI-catalyzed HBB degradation mechanism was proposed as the electron transfer between zero-valent iron and HBB, which led to the formation of four debromination products. Overall, this study provides helpful information for the practical application of CZVI in the remediation of persistent organic pollutants in the environment.