Troxerutin inhibits 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47)-induced hepatocyte apoptosis by restoring proteasome function

Environmentally realistic concentrations of chlorinated, brominated, and fluorinated persistent organic pollutants induce the unfolded protein response as a shared stress pathway in the liver of Atlantic cod (Gadus morhua)

In the North Sea and North Atlantic coastal areas, fish experience relatively high background levels of persistent organic pollutants. This study aimed to compare the mode of action of environmentally relevant concentrations of mixtures of halogenated compounds in Atlantic cod. Juvenile male cod with mean weight of 840 g were exposed by gavage to dietary mixtures of chlorinated (PCBs, DDT analogs, chlordane, lindane, and toxaphene), brominated (PBDEs), and fluorinated (PFOS) compounds for 4 weeks. One group received a combined mixture of all three compound groups. The results showed that the accumulated levels of chemicals in cod liver after 4 weeks of exposure reflected concentrations found in wild fish in this region. Pathway analysis revealed that the treatment effects by each of the three groups of chemicals (chlorinated, brominated, and fluorinated) converged on activation of the unfolded protein response (UPR). Upstream regulator analysis predicted that almost all the key transcription factors (XBP1, ERN1, ATF4, EIF2AK3, and NFE2L2) regulating the UPR were significantly activated. No additive effect was observed in cod co-treated with all three compound groups. In conclusion, the genome-wide transcriptomic study suggests that the UPR pathway is a sensitive common target of halogenated organic environmental pollutants in fish.

Toxic Effects and Mechanisms of Polybrominated Diphenyl Ethers

Polybrominated diphenyl ethers (PBDEs) are a group of flame retardants used in plastics, textiles, polyurethane foam, and other materials. They contain two halogenated aromatic rings bonded by an ester bond and are classified according to the number and position of bromine atoms. Due to their widespread use, PBDEs have been detected in soil, air, water, dust, and animal tissues. Besides, PBDEs have been found in various tissues, including liver, kidney, adipose, brain, breast milk and plasma. The continued accumulation of PBDEs has raised concerns about their potential toxicity, including hepatotoxicity, kidney toxicity, gut toxicity, thyroid toxicity, embryotoxicity, reproductive toxicity, neurotoxicity, and immunotoxicity. Previous studies have suggested that there may be various mechanisms contributing to PBDEs toxicity. The present study aimed to outline PBDEs' toxic effects and mechanisms on different organ systems. Given PBDEs' bioaccumulation and adverse impacts on human health and other living organisms, we summarize PBDEs' effects and potential toxicity mechanisms and tend to broaden the horizons to facilitate the design of new prevention strategies for PBDEs-induced toxicity.

The creation of selenium nanoparticles decorated with troxerutin and their ability to adapt to the tumour microenvironment have therapeutic implications for triple-negative breast cancer

The unique use of selenium–troxerutin nanoconjugates as an effective management therapy for treating TNBC.

Troxerutin attenuates insulin resistance via pancreatic IL-22/JAK1/STAT3 signaling activation in dihydrotestosterone-induced polycystic ovary syndrome rats

Polycystic ovary syndrome (PCOS) is an extremely common endocrine-metabolic disorder and the main cause of infertility in premenopausal women, thus targeted treatments are sorely needed. Accumulative evidence showed that exogenous supplementation of IL-22 in PCOS mice may be of significant positive effect on insulin resistance (IR), a root causative factor for this condition, but much remained unknown about its mechanism. According to our previous study, troxerutin, a common anticoagulant and thrombolytic agent in clinic, alleviated various PCOS-like phenotypes in dihydrotestosterone (DHT)-treated rat model with unclear mechanism. Here, glucose tolerance tests (GTTs), insulin tolerance tests (ITTs), and homeostatic model assessment of insulin resistance (HOMA-IR) analyses revealed that troxerutin treatment in DHT-treated rats also significantly improved insulin resistance and enhanced serum IL-22 levels, which thereby activated IL-22R1/Janus kinase 1 (JAK1)/signal transducer and activator of transcription-3 (STAT3) signaling pathway in pancreatic islet. This protective effect of troxerutin on insulin resistance improvement was blocked by an inhibitor of p-STAT3, S3I-201. Troxerutin administration to DHT rats decreased the relative abundance of Bifidobacterium and enhanced secondary bile acid profiles, which were positively correlated with serum IL-22 concentration. Conclusively, the present study reported that troxerutin is an endogenous enhancer of IL-22 and the effect of troxerutin on insulin resistance improvement was via IL-22R1/JAK1/STAT3 signaling activation in a DHT-induced PCOS rat model. These insights may be translated into a primary therapeutic agent for PCOS with insulin resistance and hyperandrogenism.NEW & NOTEWORTHY Troxerutin decreased the relative abundance of Bifidobacterium, along with enhancement of secondary bile acids/IL-22 system, which thereby activated its downstream IL-22R1/JAK1/STAT3 signaling pathway in pancreatic β cells, subsequently attenuated insulin resistance (IR), hyperandrogenism and PCOS-like phenotypes in DHT-induced PCOS rat models. Troxerutin is an endogenous IL-22 enhancer and may be of therapeutic value for PCOS with insulin resistance.

Troxerutin alleviates kidney injury in rats via PI3K/AKT pathway by enhancing MAP4 expression

Background

Troxerutin is a flavonoid compound and possesses potential anti-cancer, antioxidant, and anti-inflammatory activities. Besides, cisplatin is one of the most widely used therapeutic agents, but the clinical uses of cisplatin are often associated with multiple side effects, among which nephrotoxicity is more common.

Objective and design

This study explored the protective effects of troxerutin (150 mg kg⁻¹ day⁻¹ for 14 days) against cisplatin-induced kidney injury and the potential mechanism using Wistar rats as an experimental mammalian model.

Results

We discovered that troxerutin could significantly alleviate cisplatin-induced renal dysfunction, such as increased levels of blood urea nitrogen and creatinine (P < 0.01), as well as improved abnormal renal tissue microstructure and ultrastructure. Additionally, troxerutin significantly decreased malondialdehyde (MDA), hydrogen peroxide (H₂O₂), NO, inducible nitric oxide synthase (iNOS) levels (P < 0.01), p-NF-κB p65/NF-κB p65, TNF-α, Pro-IL-1β, IL-6, B cell lymphoma-2 (Bcl-2)/Bcl-xl associated death promoter (Bad), Cytochrome C (Cyt C), Cleaved-caspase 9, Cleaved-caspase 3, and Cleaved-caspase 8 protein levels (P < 0.01) in the kidney tissues of cisplatin-treated rats; and increased superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), total antioxidant capacity (T-AOC) activities (P < 0.01), IL-10, Bcl-2 protein levels (P < 0.01).

Conclusion

These results suggested that the underlying mechanism might be attributed to the regulation of Phosphoinositide 3 kinase/Protein kinase B (PI3K/AKT) pathway via enhancing MAP4 expression to attenuate cellular apoptosis, alleviating oxidative stress and inflammatory response.

Troxerutin-Mediated Complement Pathway Inhibition is a Disease-Modifying Treatment for Inflammatory Arthritis

Troxerutin (TXR) is a phytochemical reported to possess anti-inflammatory and hepatoprotective effects. In this study, we aimed to exploit the antiarthritic properties of TXR using an adjuvant-induced arthritic (AIA) rat model. AIA-induced rats showed the highest arthritis score at the disease onset and by oral administration of TXR (50, 100, and 200 mg/kg body weight), reduced to basal level in a dose-dependent manner. Isobaric tags for relative and absolute quantitative (iTRAQ) proteomics tool were employed to identify deregulated joint homogenate proteins in AIA and TXR-treated rats to decipher the probable mechanism of TXR action in arthritis. iTRAQ analysis identified a set of 434 proteins with 65 deregulated proteins (log₂ case/control≥1.5) in AIA. Expressions of a set of important proteins (AAT, T-kininogen, vimentin, desmin, and nucleophosmin) that could classify AIA from the healthy ones were validated using Western blot analysis. The Western blot data corroborated proteomics findings. In silico protein–protein interaction study of tissue-proteome revealed that complement component 9 (C9), the major building blocks of the membrane attack complex (MAC) responsible for sterile inflammation, get perturbed in AIA. Our dosimetry study suggests that a TXR dose of 200 mg/kg body weight for 15 days is sufficient to bring the arthritis score to basal levels in AIA rats. We have shown the importance of TXR as an antiarthritic agent in the AIA model and after additional investigation, its arthritic ameliorating properties could be exploited for clinical usability.

Medicinal plants used against hepatic disorders in Bangladesh: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Liver disease is a major cause of illness and death worldwide which accounts for approximately 2 million deaths per year worldwide, 1 million due to complications of cirrhosis and 1 million due to viral hepatitis and hepatocellular carcinoma. That's why it is seeking the researchers' attention to find out the effective treatment strategies. Phytochemicals from natural resources are the main leads for the development of noble hepatoprotective drugs. The majority of the natural sources whose active compounds are currently employed actually have an ethnomedical use. Ethnopharmacological research is essential for the development of these bioactive compounds. These studies not only provide scientific evidence on medicinal plants utilized for particular therapeutic purposes, but they also ensure cultural heritage preservation. Plenty of experimental studies have been well-documented that the ethnomedicinal plants are of therapeutics' interest for the advanced pharmacological intervention in terms of hepatic disorders.

AIM OF THE STUDY

This study summarizes the processes of hepatotoxicity induced by various toxins and explores identified hepatoprotective plants and their phytoconstituents, which can guide the extraction of novel phytochemical constituents from plants to treat liver injury. This review aimed to summarize the hepatoprotective activity of Bangladeshi medicinal plants where the bioactive compounds may be leads for the drug discovery in future.

MATERIALS AND METHODS

Literature searches in electronic databases, such as Web of Science, Science Direct, SpringerLink, PubMed, Google Scholar, Semantic Scholar, Scopus, BanglaJOL, and so on, were performed using the keywords 'Bangladesh', 'ethnomedicinal plants', 'Hepatoprotective agents' as for primary searches, and secondary search terms were used as follows, either alone or in combination: traditional medicine, medicinal plants, folk medicine, liver, hepatitis, therapeutic uses, and anti-inflammatory. Besides, several books, including the book entitled "Medicinal plants of Bangladesh: chemical constituents and uses" authored by Abdul Ghani, were carefully considered, which contained pharmacological properties and phytoconstituents of many medicinal plants growing and traditionally available in Bangladesh. Among them, the most promising plant species with their latest therapeutic effects against hepatic disorders were deeply considered in this review.

RESULTS

The results of this study revealed that in most cases, therapy using plant extracts stabilized altered hepatic biochemical markers induced by hepatotoxins. Initially, we investigated 32 plant species for hepatoprotective activity, however after extensive literature searching; we observed that 20 plants offer good pharmacological evidence of hepatoprotective function. Consequently, most bioactive compounds derived from the herbs including berberine, thymoquinone, andrographolide, ursolic acid, luteolin, naringenin, genistein, quercetin, troxerutin, morin, epigallocatechin-3-gallate, chlorogenic acid, emodin, curcumin, resveratrol, capsaicin, ellagic acid, etc. are appeared to be effective against hepatic disorders.

CONCLUSIONS

Flavonoids, phenolic acids, monoterpenoids, diterpenoids, triterpenoids, alkaloids, chromenes, capsaicinoids, curcuminoids, and anthraquinones are among the phytoconstituents were appraised to have hepatoprotective activities. All the actions displayed by these ethnomedicinal plants could make them serve as leads in the formulation of drugs with higher efficacy to treat hepatic disorders.

High-fat diet exacerbated decabromodiphenyl ether-induced hepatocyte apoptosis via intensifying the transfer of Ca2+ from endoplasmic reticulum to mitochondria

Polybrominated diphenyl ether (PBDE) as the flame retardant is heavily used in daily necessities, causing adverse health effects on humans. This study aimed to evaluate the hepatotoxicity of decabromodiphenyl ether (BDE-209), the most widely used PBDE, in lean and high-fat diet (HFD)-treated obese mice and elucidate the underlying mechanism. Firstly, the increasing levels of TG and proinflammatory factors in the liver and ALT and AST in serum demonstrated the hepatic damage caused by BDE-209 and further exacerbated by HFD. Tunel image revealed that BDE-209 induced more severe hepatocyte apoptosis with the assistant of HFD. Next, the mechanism analysis showed that the pro-apoptotic action of BDE-209 was in an endoplasmic reticulum (ER)/Ca²⁺ flux/mitochondria-dependent manner, concluded from the impairment of mitochondrial membrane potential, the enhancive protein expression of p-PERK/PERK, p-IRE1/IRE1, ATF6, CHOP, Bax/Bcl-2, cleaved caspase-3/caspase-3, IP3R1 and Sig-1R, and the over-transfer of Ca²⁺ from ER to mitochondria. Such proposed mechanism was further confirmed by the IP3R1 siRNA transfection cell experiment, where apoptotic rate was reduced in parallel with the reduced mitochondrial Ca²⁺ level. Finally, the higher expression of PACS-2 protein and the expanded ER contributed to the enriched ER-mitochondria interaction, reflected by the closer distance between ER and mitochondria visually displayed in the TEM image in HFD groups. This change was conducive to the rapid delivery of apoptosis signals via Ca²⁺, as proven, mechanically explaining the strengthening effect of HFD on BDE-209 hepatotoxicity. These findings detailedly explained the mechanism of BDE-209 hepatotoxicity and clarified the auxiliary effect of HFD, providing a theoretical basis for further studying other analogs.

Oxidative stress and endoplasmic reticulum stress contributed to hepatotoxicity of decabromodiphenyl ethane (DBDPE) in L-02 cells

Decabromodiphenyl ethane (DBDPE) is one of the most commonly used novel brominated flame retardants (NBFRs), and its mass production and widespread application have caused health threats to the human being. Existing studies have shown that DBDPE has hepatotoxicity. And we have found that DBDPE could change cytochrome P450 3A (CYP3A) expression levels in rat livers, whereas the mechanism is unclear. In this study, we exposed human normal hepatocyte (L-02) to DBDPE to further study the effect and mechanism of DBDPE on hepatocellular injury and liver metabolic enzyme CYP3A changes in vitro. The results showed that DBDPE caused L-02 cell viability decrease, lactate dehydrogenase (LDH) and transaminase release, ultrastructural damage, and apoptosis. Moreover, DBDPE exposure induced oxidative stress (i.e., increased ROS generation and MDA levels and decreased GSH content, SOD activity, and mitochondrial membrane potential) and endoplasmic reticulum (ER) stress in L-02 cells as evidenced by the elevated PERK and IRE-1α expression levels. These results confirmed that DBDPE is toxic to hepatocytes. Besides, the CYP3A expression level was decreased in DBDPE exposed L-02 cells. However, pretreatment of L-02 cells with antioxidant N-Acetyl-l-cysteine (NAC) and endoplasmic reticulum stress inhibitor 4-PBA inhibited DBDPE-induced oxidative stress, endoplasmic reticulum stress, CYP3A expression decrease, and apoptosis. Therefore, we demonstrated that DBDPE could exert toxic effects and decrease CYP3A expression on L-02 cells by inducing ER stress and oxidative stress.

Hesperidin prevents the combined toxicity of decabromodiphenyl ether and sodium nitrite in vitro

Decabromodiphenyl ether (BDE-209) and Sodium nitrite (SN) coexist in the processing meat and fish foods, but there is no research considering them together. The present study aimed to investigate the binary mixture's toxicity of BDE-209 and SN and explore the protective effect of hesperidin (Hsp) on the combined toxicity. Results showed that compared with the impact of BDE-209 or SN alone, the binary mixture had a synergistic toxic effect on impairing the viability of HepG2 cells, accompanied by oxidative stress, Ca²⁺ accumulation, mitochondrial dysfunction. The increase of γ-H2AX fluorescent foci and micronuclei number also indicated its genotoxicity. Pretreatment of Hsp could significantly alleviate the above damage caused by the binary combination. These findings revealed the toxicological interaction of BDE-209 and SN and highlighted that food containing abundant natural flavonoids, as hesperidin, could reduce this toxicological risk.

Roles of endoplasmic reticulum stress in 2,2',4,4'-tetrabromodiphenylether-induced thyroid cell apoptosis and autophagy

Polybrominated diphenyl ethers are known to be toxic and impair thyroid function. However, the underlying molecular mechanisms are not well understood. We constructed a female Sprague-Dawley rat model to evaluate the role of endoplasmic reticulum stress, apoptosis and autophagy in 2,2',4,4'-tetrabromodiphenylether (PBDE-47) induced thyroid toxicity. In the brain development spurt period (postnatal day 10), rats were treated with PBDE-47 (0, 1, 5, 10 mg/kg bw, i.g). Two addition groups were administered with 4-Phenylbutyric acid, an endoplasmic reticulum stress modulator, to reverse PBDE-47-induced thyroid toxicity. Our results demonstrated that PBDE-47 significantly decreased serum thyroid stimulating hormone levels, induced histologic changes in thyroid tissues, increased the percentage of cell apoptosis and expression levels of C/EBP-homologous protein, caspase 3, glucose-regulated protein 78, inositol-requiring enzyme 1, and autophagy-related proteins Beclin1 and 1A/1B-light chain 3. Besides of decreased serum thyroid stimulating hormone levels, all these changes were reversed by 4-Phenylbutyric acid. Taken together, these data indicate that, PBDE-47 damages the thyroid tissues by triggering endoplasmic reticulum stress, apoptosis and autophagy.

Can troxerutin pretreatment prevent testicular complications in prepubertal diabetic male rats?

OBJECTIVE

The vast majority of type 1 diabetes leads to a higher prevalence of reproductive system's impairments. Troxerutin has attracted much attention owing to its favorable properties, including antihyperglycemic, anti-inflammatory, and antiapoptotic effects. This investigation was proposed to evaluate whether pretreatment with troxerutin could prevent apoptosis-induced testicular disorders in prepubertal diabetic rats.

METHODS

Fifty prepubertal male Wistar rats were randomly allocated into five groups: control (C), troxerutin (TX), diabetic (D), diabetic+troxerutin (DTX), and diabetic+insulin (DI). Diabetes was induced by 55 mg/kg of streptozotocin applied intraperitoneally. In TX and DTX groups, 150 mg/kg troxerutin was administered by oral gavage. Diabetic rats in DI group received 2-4 U NPH insulin subcutaneously. Troxerutin and insulin treatments were begun immediately on the day of diabetes confirmation. After 30 days, the testicular lipid peroxidation and antioxidant activity, apoptosis process, and stereology as well as serum glucose and insulin levels were assessed.

RESULTS

The results showed that diabetes caused a significant increase in the blood glucose, the number of TUNEL positive cells and tubules, and the malondialdehyde level as well as a significant decrease in serum insulin level compared to controls. The stereological analysis also revealed various alterations in diabetic rats compared to controls. Troxerutin treatment improved these alterations compared to the diabetic group.

CONCLUSION

Troxerutin-pretreatment may play an essential role in the management of the type-1 diabetes-induced testicular disorders by decreasing blood glucose and modulating apoptosis.

Biological and Therapeutic Effects of Troxerutin: Molecular Signaling Pathways Come into View

Flavonoids consist a wide range of naturally occurring compounds which are exclusively found in different fruits and vegetables. These medicinal herbs have a number of favourable biological and therapeutic activities such as antioxidant, neuroprotective, renoprotective, anti-inflammatory, anti-diabetic and anti-tumor. Troxerutin, also known as vitamin P4, is a naturally occurring flavonoid which is isolated from tea, coffee and cereal grains as well as vegetables. It has a variety of valuable pharmacological and therapeutic activities including antioxidant, anti-inflammatory, anti-diabetic and anti-tumor. These pharmacological impacts have been demonstrated in in vitro and in vivo studies. Also, clinical trials have revealed the efficacy of troxerutin for management of phlebocholosis and hemorrhoidal diseases. In the present review, we focus on the therapeutic effects and biological activities of troxerutin as well as its molecular signaling pathways.

Troxerutin Improves Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Screening potential compounds for improving ulcerative colitis (UC) from clinical medication is an effective strategy for drug repurposing. We applied bioinformatics and network pharmacology to the drug screening process in this study, which helped us to screen out troxerutin that could improve UC. Troxerutin belongs to flavonoids and is used clinically as an anticoagulant and thrombolytic agent. This study found a new pharmacological activity of troxerutin, that is, it had a significant improvement effect on UC in mice. Experimental results of in vitro and in vivo levels showed that troxerutin could effectively reduce the level of oxidative stress that caused damages in intestinal epithelial cells and colonic tissue, maintain the distribution and expression of tight junction-related proteins, and protect the barrier function of colon tissue. In addition to the oxidative stress, severe inflammatory response is also an important pathological factor that aggravates UC. However, troxerutin could reduce the infiltration of inflammatory cells in the colon tissue and decrease the expression of inflammation-related proteins and proinflammatory cytokines. Due to its antioxidant and anti-inflammatory effects, troxerutin inhibited the process of cell apoptosis in the colon tissue and relieved the degree of colonic fibrosis. Bioinformatics analysis showed that the ameliorating effect of troxerutin on UC was probably related to its network regulation of signaling pathways. In summary, we discovered a new pharmacological activity of the flavonoid troxerutin against UC, which is conducive to the expansion and application of flavonoids in the treatment of human diseases.

BDE-47 induced apoptosis in zebrafish embryos through mitochondrial ROS-mediated JNK signaling

2,2,4,4-tetrabromodiphenyl ether (BDE-47) has received considerable attention because of its high detection level in biological samples and potential developmental toxicity. Here, using zebrafish (Danio rerio) as the experimental animal, we investigated developmental effects of BDE-47 and explored the potential mechanism. Zebrafish embryos at 4 h post-fertilization (hpf) were exposed to 0.312, 0.625 and 1.25 mg/L BDE-47 to 74-120 hpf. We found that BDE-47 instigated a dose-related developmental toxicity, evidenced by reduced embryonic survival and hatching rate, shortened body length and increased aberration rate. Meanwhile, higher doses of BDE-47 reduced mitochondrial membrane potential and ATP production but increased apoptosis in zebrafish embryos. Expression of genes involved in mitochondrial oxidative phosphorylation (OXPHOS) (ndufb8, sdha, uqcrc1, cox5ab and atp5fal) were negatively related to BDE-47 doses in zebrafish embryos. Moreover, exposure to BDE-47 at 0.625 or 1.25 mg/L impaired mitochondrial biogenesis and mitochondrial dynamics. Our data further showed that BDE- 47 exposure induced excessive reactive oxygen species (ROS) and oxidative stress, which was accompanied by the activation of c-Jun N-terminal Kinase (JNK). Antioxidant NAC and JNK inhibition could mitigate apoptosis in embryos and improve embryonic development in BDE-47-treated zebrafish, suggesting the involvement of ROS/JNK pathway in embryonic developmental changes induced by BDE-47. Altogether, our data suggest here that developmental toxicity of BDE-47 may be associated with mitochondrial ROS-mediated JNK signaling in zebrafish embryo.

Enhanced apoptogenesis and oncogene regulatory mechanism of troxerutin in triple negative breast cancer cells

Triple negative breast carcinoma (TNBC) is an aggressive form of cancer, with high rates of morbidity, mortality, poor prognosis and limited therapeutic options. The objective of the present study was to elaborate the anticancer activity of Troxerutin (TXN) in TNBC/MDA-MB-231 cells. Herein, we demonstrated the inhibitory effects of TXN on the breast cancer cell growth via induction of apoptosis. Mitochondrial membrane potential (∆Ψm), DNA damage and apoptotic nuclear changes were analyzed by flowcytometry, AO/EtBr and Hoechst staining, respectively. Furthermore, apoptotic protein and gene expressions were analyzed by western blot and reverse transcription polymerase chain reaction (RT-PCR), respectively. Our results indicated that TXN induces apoptosis as evidenced by inhibit the cell proliferation, enhanced apoptotic activation, altered mitochondrial membrane potential and elevated level of DNA damage in TNBC cells. Furthermore, the TXN inhibit anti-apoptotic protein expression with the subsequent upregulation of Cytochrome c, Caspase-9 and Caspase-3. Thus, TXN induces apoptosis in TNBC cells through inducing nuclear damage and altered apoptotic marker expressions. Therefore, TXN might be used as a potential therapeutic agent for the treatment of triple negative breast cancer.

Perinatal low-dose PBDE-47 exposure hampered thyroglobulin turnover and induced thyroid cell apoptosis by triggering ER stress and lysosomal destabilization contributing to thyroid toxicity in adult female rats

Evidence demonstrates that 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) is able to disturb thyroid hormones (THs) homeostasis, yet the mechanisms remain unknown. We sought to investigate the effects of PBDE-47 on endoplasmic reticulum (ER) and lysosomes in thyroids. Using female Sprague-Dawley rats orally administered PBDE-47 at environmentally relevant doses (0.1, 1.0, 10 mg/kg/day) beginning ten days before breeding and ending at weaning, we showed that perinatal PBDE-47 exposure resulted in a reduction in serum THs levels and relative thyroid weight in adult female rats. These were accompanied by thyroid structural abnormalities with cell apoptosis. Mechanistically, PBDE-47 caused ER stress and activation of unfolded protein response (UPR). Moreover, PBDE-47 elicited lysosomal membrane permeabilization and the release of cathepsin. Importantly, the apoptotic cells co-localized with IRE1α, a stress sensor protein of UPR branch that mediates ER stress-induced apoptosis, or cathepsin B, a lysosomal cysteine protease that is involved in thyroglobulin, the precursor of THs, degradation and apoptosis induction. Interestingly, thyroglobulin was accumulated and predominantly presented in cells harboring compromised ER or lysosomal activity. Collectively, our findings suggest that perinatal low-dose PBDE-47 exposure hampers thyroglobulin turnover and induces thyroid cell apoptosis by triggering ER stress and lysosomal destabilization contributing to thyroid toxicity in adult female rats.

Troxerutin downregulates C/EBP-β gene expression via modulating the IFNγ-ERK1/2 signaling pathway to ameliorate rotenone-induced retinal neurodegeneration

Troxerutin, a natural flavonoid guards against oxidative stress and apoptosis with a high capability of passing through the blood-brain barrier. Our aim was to investigate the role of troxerutin in experimentally induced retinal neurodegeneration by modulating the interferon-gamma (IFNγ)-extracellular signal-regulated kinases 1/2 (ERK1/2)-CCAAT enhancer-binding protein β (C/EBP-β) signaling pathway. Three groups of rats (10 each group) were included. Group I (control group), group II (rotenone treated group): the rats were injected subcutaneously with a single rotenone dosage of 3 mg/kg repeated every 48 hours for 60 days to trigger retinal neurodegeneration. Group III (troxerutin-treated group): rats received troxerutin (150 mg/kg/day) by oral gavage 1 hour before rotenone administration. A real-time polymerase chain reaction technique was applied to measure messenger RNA (mRNA) levels of retinal C/EBP-β. Enzyme-linked immunosorbent assay technique was utilized to assay tumor necrosis factor-α (TNF-α), IFNγ, and ERK1/2 levels. Finally, reactive oxygen species (ROS), as well as carbonylated protein (CP) levels, were assessed spectrophotometrically. Improved retinal neurodegeneration by downregulation of C/EBP-β mRNA gene expression, also caused a significant reduction of TNF-α, IFNγ, ERK1/2 as well as ROS and CP levels compared with the diseased group. These findings could hold promise for the usage of troxerutin as a protective agent against rotenone-induced retinal neurodegeneration.

2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) induces mitochondrial dysfunction and related liver injury via eliciting miR-34a-5p-mediated mitophagy impairment

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) is associated with various adverse human health effects; however, the knowledge of its toxicity is still very limited. Mitochondrial injury has been observed in liver cells exposed to BDE-47 in vitro. Mitophagy impairment causes the accumulation of dysfunctional mitochondria, contributing to the pathological mechanisms of liver injury. The aim of this study was to investigate whether BDE-47 impairs mitophagy to trigger mitochondrial dysfunction-related liver injury and the underlying mechanisms. This study revealed that BDE-47 elicited mitochondrial dysfunction and related oxidative liver injury by impairing mitophagy. Moreover, our results showed that NAD⁺ insufficiency is responsible for BDE-47-mediated mitophagy defect and mitochondrial dysfunction in mouse livers, which was associated with suppression of Sirt3/FoxO3a/PINK1 signaling. Furthermore, our results indicated a potential role of miR-34a-5p in the hepatotoxicity of BDE-47. Mechanistically, BDE-47 dramatically upregulated miR-34a-5p expression in mouse livers. The data from AAV-sponge-mediated miR-34a-5p inhibition suggested that miR-34a-5p diminished NAD⁺ level by directly targeting NAMPT expression in BDE-47-treated mouse livers, which was confirmed by luciferase reporter assay. Consequently, miR-34a-5p markedly abated Sirt3/FoxO3a/PINK1 signaling-mediated mitophagy to promote mitochondrial dysfunction in BDE-47-treated mouse livers. The present study provided in vivo evidence to reveal a potential mechanism for BDE-47-induced mitochondrial dysfunction and related liver injury and indicated that miR-34a-5p-mediated mitophagy impairment might be a therapeutic target for BDE-47 toxicity.

Toxicological, gene expression and histopathological evaluations of environmentally realistic concentrations of polybrominated diphenyl ethers PBDE- 47, PBDE-99 and PBDE-209 on zebrafish embryos

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants. Biomonitoring studies have shown widespread presence of PBDEs in humans and their accumulation in food chain cause concern to human health, especially for foetus and infant development. The early-life stages are generally considered more sensitive to exposure to toxic compounds than juvenile or adults. For this reason the aim of this study was to evaluate the effects of the three most environmentally relevant BDE (BDE- 47, 99 and 209) on zebrafish embryos. The fish embryo toxicity (FET) OECD tests on zebrafish were performed followed by histopathogical examination to assess morphological changes. The gene expression of the thyroid stimulating hormone β (Tshβ), the transport proteins transthyretin (Ttr) and thyroxine-binding globulin (Tbg) as well as the enzyme iodothyronine deiodinase 1 (Dio1) was also assessed by Real-time PCR. BDE-47 and BDE-99 showed an increase of the severity of the effects at the lower concentrations while for the BDE-209 the effects were higher to the high concentrations. Although all compounds did not show any acute toxicity for none of the concentrations tested, they reported interesting sub-acute lesions, including yolk and pericardial edema, tail and head malformation, reduced and extremely reduced heart beat rate, blood stasis and spinal curvature, with the highest percentage recorded for BDE-209. Cardiac edema, damage of eye structure and hydrocephaly were confirmed also by histophatological examination. Furthermore, a toxic and dose-dependent liver vacuolization in BDE-209 was observed in all experimental groups. Although no statistically significant difference in gene expression was observed, BDE-209 up-regulated only Dio1 while the other congeners induced Tshβ, Ttr, Tbg and Dio1. Overall, this research highlighted that exposure to BDE-47, BDE-99 and BDE-209 at realistic concentrations caused lethal and sub-lethal alterations and impaired genes involved in thyroid hormones homeostasis leading to abnormal development of zebrafish embryos.

Combining an in silico approach with an animal experiment to investigate the protective effect of troxerutin for treating acute lung injury

Background

Troxerutin (TRX), a naturally occurring flavonoid in various fruits, has been reported to exhibit numerous pharmacological and biological activities in vitro and in vivo. However, the molecular mechanisms underlying TRX as a treatment for disease are poorly understood.

Methods

Using pharmacophore mapping and inverse docking, a set of potential TRX target proteins that have been associated with multiple forms of diseases was obtained. Bioinformatic analyses were performed using the Enrichr and STRING servers to analyse the related biological processes and protein-protein networks. Furthermore, we investigated the potential protective effect of TRX against lipopolysaccharide-induced acute lung injury (ALI) using a mouse model. Morphological changes in the lungs were assessed using haematoxylin and eosin staining. Inflammatory cytokines, tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-10 were investigated using ELISA. Activation of MAPK and NF-κB was detected using western blotting.

Results

Our network pharmacology analysis revealed the existence of multiple TRX-related chemical-target interactions and the related biological processes. We found that pretreatment with TRX protected against histological changes and obviously regulated the inflammatory cell counts and inflammatory cytokine levels in bronchoalveolar lavage fluid. Based on bioinformatic and western blot analyses, TRX may exert a protective effect against ALI by inhibiting MAPK and NF-κB signalling.

Conclusions

TRX can ameliorate pulmonary injury by inhibiting the MAPK and NF-κB signalling pathways and has a potential protective effect against ALI. This study may be helpful for understanding the mechanisms underlying TRX action and for discovering new drugs from plants for the treatment of ALI.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2515-7) contains supplementary material, which is available to authorized users.

Responses of antioxidant defenses in the clam Mactra veneriformis to 2,2',4,4'‑tetrabromodiphenyl ether exposure

Antioxidant enzymes play essential roles against oxidative stress caused by 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), which is ubiquitous in marine environment and organisms. However, research on antioxidant responses to BDE-47 in marine bivalves is scarce. In this study, we identified the full-length cDNA of catalase (CAT), and glutathione peroxidase (GPx) in the clam Mactra veneriformis. Subsequently, the responses of CAT, GPx, and copper, zinc-superoxide dismutase (Cu, Zn-SOD) were investigated in the clams exposed to 0.1, 1, and 10 μg/L BDE-47 for 7 days, and then depurated in natural seawater for 3 days. MvCAT and MvGPx contained conserved sequences. The deduced amino acid sequences shared high similarity with CATs and GPxs in other mollusks. M. veneriformis accumulated BDE-47 in a dose-dependent manner and eliminated BDE-47 poorly. BDE-47 induced a time- and dose-dependent increase of malondialdehyde content. Both the dose and the duration had significant effect on mRNA expressions and activities of the three antioxidants. Cu, Zn-SOD responded to BDE-47 earlier than CAT and GPx. The antioxidant responses could recover after depuration. These results suggested that M. veneriformis could accumulate BDE-47 efficiently. Antioxidant enzymes were triggered to counter the oxidative stress generated by BDE-47. Cu, Zn-SOD acted as the first defense against oxidative stress, while CAT and GPx intervened later. This study is therefore helpful in understanding the antioxidant responses to PBDEs in marine bivalves.

Perigestational exposure to low doses of PBDE-47 induces excessive ER stress, defective autophagy and the resultant apoptosis contributing to maternal thyroid toxicity

Brominated flame retardant 2,2',4,4'‑tetrabromodiphenyl ether (PBDE-47) is known to induce developmental neurotoxicity by disturbing thyroid hormones (THs). Evidence shows that maternal THs are crucial for brain development and growth of fetuses and infants. However, little is known about the effects of PBDE-47 on maternal thyroid status and its mode of action. Here, using female Sprague-Dawley rats orally exposed to low doses of PBDE-47 (0.1, 1.0, 10 mg/kg/day) from pre-pregnancy until weaning of offspring to mimic human exposure, we show that perigestational exposure to PBDE-47 elevated serum triiodothyronine and thyroxine levels in mother rats. This is accompanied by disrupted thyroid follicle structure including expanded follicles, hyperplastic epithelial cells and shed cell remnants filled in the exhausted follicular lumen. Mechanistically, PBDE-47 enhanced apoptosis in thyroid tissue, as demonstrated by Caspase-3 activation, PARP cleavage and DNA fragmentation. Further study identified that PBDE-47 upregulated the levels of GRP78, ATF4, active Caspase-12 and CHOP, suggesting endoplasmic reticulum (ER) stress and unfolded protein response activation. Moreover, PBDE-47 reduced the levels of LC3-II, an autophagy marker protein essential for the autophagosomes formation, while increased the autophagy substrate p62 accumulation, indicating autophagy defect. Importantly, the colocalization of apoptotic cells with CHOP, a key mediator of ER stress-induced apoptosis, or p62, uncovered the contribution of excessive ER stress and defective autophagy to apoptosis. Collectively, our results suggest that excessive ER stress, defective autophagy and the resultant apoptosis are implicated in maternal thyroid injury following perigestational PBDE-47 exposure, which offers insight into a better understanding of PBDE-47-induced maternal thyroid toxicity.

Troxerutin Protects Kidney Tissue against BDE-47-Induced Inflammatory Damage through CXCR4-TXNIP/NLRP3 Signaling

2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) induces oxidative stress in kidney cells, but the underlying mechanism remains poorly understood. Troxerutin, a natural flavonoid, has potential antioxidant and anti-inflammatory efficacy. In this study, we assessed the effect of troxerutin on kidney damage caused by BDE-47 and investigated the underlying mechanism. The results showed troxerutin reduced reactive oxygen species (ROS) level and urine albumin-to-creatinine ratio (ACR), decreased the activities of inflammatory factors including cyclooxygenase-2 (COX-2), induced nitric oxide synthase (iNOS) and nuclear factor kappa B (NF-κB) in the kidney tissues of BDE-47-treated mice. Furthermore, troxerutin significantly weakened the expression of kidney NLRP3 inflammasome containing NLRP3, ASC, and caspase-1, contributing to the decline of IL-1β. Additionally, troxerutin inhibited the increased protein level of stromal-derived factor-1(SDF-1), C-X-C chemokine ligand 12 receptor 4 (CXCR4), and thioredoxin interaction protein (TXNIP) caused by BDE-47. Specifically, the immunoprecipitation assay indicated that there was a direct interaction between CXCR4 and TXNIP. CXCR4 siRNA and TXNIP siRNA also decreased the inflammatory damage, which was similar to the action of troxerutin. Our data demonstrated that troxerutin regulated the inflammatory lesions via CXCR4-TXNIP/NLRP3 inflammasome in the kidney of mice induced by BDE-47.

Troxerutin down-regulates KIM-1, modulates p38 MAPK signaling, and enhances renal regenerative capacity in a rat model of gentamycin-induced acute kidney injury

Troxerutin enhances renal tissue regeneration, improves renal function, and decreases renal tissue injury in gentamycin-treated rats.

Troxerutin Reduces Kidney Damage against BDE-47-Induced Apoptosis via Inhibiting NOX2 Activity and Increasing Nrf2 Activity

2,2,4,4-Tetrabromodiphenyl ether (BDE-47), one of the persistent organic pollutants, seriously influences the quality of life; however, its pathological mechanism remains unclear. Troxerutin is a flavonoid with pharmacological activity of antioxidation and anti-inflammation. In the present study, we investigated troxerutin against BDE-47-induced kidney cell apoptosis and explored the underlying mechanism. The results show that troxerutin reduced renal cell apoptosis and urinary protein secretion in BDE-47-treated mice. Western blot analysis shows that troxerutin supplement enhanced the ratio of Bcl-2/Bax; inhibited the release of cytochrome c from mitochondria, the activation of procaspase-9 and procaspase-3, and the cleavage of PARP; and reduced FAS, FASL, and caspase-8 levels induced by BDE-47. In addition, troxerutin decreased the production of reactive oxygen species (ROS) and increased the activities of antioxidative enzymes. Furthermore, troxerutin blunted Nrf2 ubiquitylation, enhanced the activity of Nrf2, decreased the activity of NOX2, and ameliorated kidney oxidant status of BDE-47-treated mice. Together, these results confirm that troxerutin could alleviate the cytotoxicity of BDE-47 through antioxidation and antiapoptosis, which suggests that its protective mechanism is involved in the inhibition of apoptosis via suppressing NOX2 activity and increasing Nrf2 signaling pathway.

Troxerutin protects against diabetic cardiomyopathy through NF‑κB/AKT/IRS1 in a rat model of type 2 diabetes

Troxerutin is a bioflavonoid, which can be used to treat venous disorders, thrombosis and cerebrovascular diseases. Recent studies have demonstrated that it may also be used to prevent edemas. However, it is not known whether troxerutin protects against the cardiomyopathic complications of diabetes. In the present study, a rat model of type 2 diabetes was used to investigate the potential for troxerutin to protect against diabetic cardiomyopathy, through changes to nuclear factor‑κB (NF‑κB) expression. Troxerutin administration significantly reduced heart rate, blood pressure, blood glucose and plasma triglyceride levels across all measured time points. Furthermore, troxerutin significantly reduced reactive oxygen species levels, NF‑κB protein expression, and suppressed the phosphorylated forms of AKT, insulin receptor substrate 1 (IRS1) and c‑Jun N‑terminal kinase (JNK). These results suggested that troxerutin protects against cardiomyopathy via alterations in NF‑κB, AKT and IRS1 signaling, in a rat model of type 2 diabetes.

Troxerutin Attenuates Enhancement of Hepatic Gluconeogenesis by Inhibiting NOD Activation-Mediated Inflammation in High-Fat Diet-Treated Mice

Recent evidence suggests that troxerutin, a trihydroxyethylated derivative of natural bioflavonoid rutin, exhibits beneficial effects on diabetes-related symptoms. Here we investigated the effects of troxerutin on the enhancement of hepatic gluconeogenesis in high-fat diet (HFD)-treated mice and the mechanisms underlying these effects. Mice were divided into four groups: Control group, HFD group, HFD + Troxerutin group, and Troxerutin group. Troxerutin was treated by daily oral administration at doses of 150 mg/kg/day for 20 weeks. Tauroursodeoxycholic acid (TUDCA) was used to inhibit endoplasmic reticulum stress (ER stress). Our results showed that troxerutin effectively improved obesity and related metabolic parameters, and liver injuries in HFD-treated mouse. Furthermore, troxerutin significantly attenuated enhancement of hepatic gluconeogenesis in HFD-fed mouse. Moreover, troxerutin notably suppressed nuclear factor-κB (NF-κB) p65 transcriptional activation and release of inflammatory cytokines in HFD-treated mouse livers. Mechanismly, troxerutin dramatically decreased Nucleotide oligomerization domain (NOD) expression, as well as interaction between NOD1/2 with interacting protein-2 (RIP2), by abating oxidative stress-induced ER stress in HFD-treated mouse livers, which was confirmed by TUDCA treatment. These improvement effects of troxerutin on hepatic glucose disorders might be mediated by its anti-obesity effect. In conclusion, troxerutin markedly diminished HFD-induced enhancement of hepatic gluconeogenesis via its inhibitory effects on ER stress-mediated NOD activation and consequent inflammation, which might be mediated by its anti-obesity effect.