Daphnetin Mitigates Ovalbumin-Induced Allergic Rhinitis in Mice by Regulating Nrf2/HO-1 and TLR4/NF-kB Signaling

Abstract

Background

Allergic rhinitis (AR) is an inflammatory disorder of nasal mucosa resulting from allergen exposure. Daphnetin (DAP) is a coumarin derivative that has various bioactivities. Nevertheless, its specific function in AR is unclear.

Objectives

This study is aimed to explore the specific function of DAP in AR.

Methods

An AR murine model was established by ovalbumin (OVA) induction. Murine sneezing and rubbing behaviors were observed. Hematoxylin-eosin was used for histopathological observation of nasal mucosa. ELISA was utilized for detection of cytokine production in murine serum. Oxidative stress-associated markers were assessed by commercial assay kits. Western blotting was utilized for evaluating protein levels of Toll-like receptor 4 (TLR4) and nuclear factor kappa B (NF-κB) in nasal mucosa.

Results

DAP alleviated OVA-induced nasal symptoms, inflammatory response and oxidative stress in the AR murine model. DAP activated nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling and inactivated TLR4/NF-κB signaling in murine nasal mucosa.

Conclusion

DAP mitigates OVA-induced AR in mice by activating Nrf2/HO-1 signaling and inactivating TLR4/NF-κB signaling.

Keywords

allergic rhinitis daphnetin ovalbumin Nrf2/HO-1 and TLR4/NF-κB

Introduction

Allergic rhinitis (AR) is a chronic inflammatory disorder of the nasal mucosa affecting approximately 10%–25% of the population worldwide.¹ The main symptoms of AR include nasal congestion, nasal itching, sneezing, and rhinorrhea.² AR is induced by antigen exposure which triggers the increase of immune cells, production of antigen-specific immunoglobulin E (IgE), and release of allergic mediators and cytokines.³ For AR treatment, antihistamines and corticosteroids are effective options currently to attenuate the symptoms of AR; however, these approaches exhibit a transient efficacy and increased side effects.⁴ Although AR is not a life-threatening disorder, it adversely impacts the life quality of affected individuals in many aspects such as sleep and work.⁵ Hence, finding a more effective and practical approach for AR treatment is of great value.

Daphnetin (DAP; 7,8-dihydroxycoumarin) is a coumarin derivative extracted from Daphne Korean Nakai.⁶ Accumulating evidence has illustrated that DAP exerts broad biological activities including anti-tumor, antioxidant, anti-inflammatory, and anticoagulant and antimicrobial^6,7 Clinically, DAP has been approved an adjunctive therapy for cardiovascular diseases in China with few side effects.^8,9 DAP was found to suppress proliferation and inflammation in human HaCaT keratinocytes as well as attenuate skin lesion in an imiquimod-induced murine model for psoriasis.¹⁰ DAP attenuates high glucose-induced inflammatory response, oxidative stress, and extracellular matrix deposition in human glomerular mesangial cells.¹¹ Moreover, DAP alleviates inflammation and oxidative stress to protect against the nephrotoxicity induced by cisplatin.¹² Importantly, DAP was reported to have an immunosuppressive activity which inhibits humoral immune response in a murine model. ⁹ Nevertheless, to our knowledge, whether DAP also protects against AR has not been clarified.

Oxidative stress resulting from excessive production of reactive oxygen species (ROS) has been reported to be closely correlated to the development of AR.^13,14 ROS enhances mucosa permeability and mucus production and leads to the secretion of inflammatory mediators.¹⁵ Studies have demonstrated that the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway plays a crucial part in oxidative stress.¹⁶ Nrf2 transcriptionally interacts with its downstream HO-1 protein, thereby actuating the antioxidant effect of HO-1.¹⁶ Toll-like receptor 4 (TLR4), a member of the pattern recognition receptor family, acts as a main initiator of inflammatory response.¹⁷ TLR4 can induce the activation of nuclear factor kappa B (NF-κB) which further promotes the inflammatory response, consequently aggravating AR.¹⁸ Studies have demonstrated the significance of Nrf2/HO-1 and TLR4/NF-κB signaling pathways in the development of AR.^19,20 Furthermore, it was indicated that DAP alleviated pancreatitis by modulating TLR4/NF-κB signaling.²¹ DAP protects against complete Freund’s adjuvant-induced inflammatory pain via Nrf2/HO-1 and NF-κB signaling.²² However, it is unclear whether Nrf2/HO-1 and TLR4/NF-κB signaling pathways are involved in DAP-mediated AR.

Herein, we examined the function of DAP in an ovalbumin (OVA)-induced murine model for AR. It was hypothesized that DAP might affect inflammatory response and oxidative stress in AR mice by regulating TLR4/NF-κB and Nrf2/HO-1 signaling pathways. The results might provide a new perspective for treating AR.

Materials and Methods

Animal Model

Thirty-two C57BL/6 mice (female, 6–8 weeks) were purchased from Vital River (Beijing, China). Mice were randomly grouped as: PBS, OVA, OVA + DAP and OVA + DEX, with eight mice per group. The OVA-induced AR mouse model was established according to previous description.^2,23 Briefly, mice in model groups were intraperitoneally injected with 200 µL phosphate-buffered saline (PBS) containing 50 µg OVA (Sigma-Aldrich, St. Louis, MO, USA) and 5 mg aluminum hydroxide (Sigma-Aldrich) on days 0, 7, and 14. The mice were intranasally administrated with 20 µL PBS containing 400 µg OVA on days 21, 23, 25, and 27. On days 21–27, mice in drug-treated groups were orally administrated with 5 mg/kg DAP (PharmaBlock, Sciences, Nanjing, China).^24,25 or 1 mg/kg dexamethasone (DEX, Sigma-Aldrich).²³ as the positive control once daily. A group of mice were treated with the same amount of PBS without OVA induction or drug treatment as the negative control. On day 27, the frequency of sneezing and rubbing behaviors was counted for 15 min. On day 28, all mice were sacrificed by intraperitoneally injecting with Alfaxan (Jurox Pty Ltd, Rutherford, NSW, Australia). Then, blood samples and nasal mucosa were collected and stored at −80°C for subsequent analysis. All animal experiments were performed following the Guide for Care and Use of Laboratory Animals and approved by the Animal Research Ethics Committee of Wuhan Hualianke Biotechnology Co., Ltd (approval number: 202108133).

Hematoxylin-Eosin (HE) Staining

Murine nasal mucosa was paraffin-embedded and cut into sections (4-µm-thick). Then, tissue sections were dewaxed in xylene and rehydrated in gradient ethanol. Afterward, the sections were stained with hematoxylin for 15 min, treated with 5% acetic acid and rinsed in distilled water followed by staining with eosin (Sigma-Aldrich) for 10 min. After dehydrated with graded ethanol, washed with xylene and sealed with Canada balsam (Sigma-Aldrich), nasal mucosa was observed under a microscope (Olympus, Tokyo, Japan).

Enzyme-Linked Immunosorbent Assay (ELISA)

Murine blood samples were subjected to centrifugation at 1000 × g for 10 min at 4°C to collect serum. ELISA was used to detect concentrations of histamine (Abcam, Cambridge, MA, USA), OVA-specific IgE (BioLegend, San Diego, Washington, USA), tumor necrosis factor-α (TNF-α, Abcam) and interleukin 5 (IL-5, Abcam) in murine serum. The levels of Nrf2 and HO-1 in murine nasal mucosa were examined by corresponding ELISA kits (R&D Systems, Minneapolis, MN, USA) according to the protocols of manufacturer.

Measurement of Oxidative Stress Markers

Nasal mucosa samples were homogenized on ice in 1 mL sodium chloride solution (0.9%) and subjected to centrifugation at 3000 rpm for 10 min at 4°C. Then, the supernatants were harvested to assess superoxide diamutase (SOD) activity, malondialdehyde (MDA) level and myeloperoxidase (MPO) level with SOD assay kit, MDA assay kit and MPO assay kit (all from Jiancheng Bioengineering Institute, Nanjing, China), respectively, following the instructions of manufacturer. For detection of ROS level, tissue homogenate was treated with DCFH-DA fluorescent probe (10 μmol/L; BestBio Science, Shanghai, China) and cultured for 20 min at 37°C. After rinsing with PBS three times, a fluorescence microplate reader was used to detect fluorescence intensity of dichlorofluorescein. The excitation wavelength was 502 nm, and the emission wavelength was 530 nm.

Western Blotting

Proteins were isolated from murine nasal mucosa using RIPA buffer (Thermo Scientific, Waltham, MA, USA) and quantified with a BCA assay kit (Thermo Scientific). Then, equal amounts of protein samples (20 μg) were separated by 10% SDA-PAGE and blotted on polyvinylidene difluoride (PVDF) membranes (Thermo Scientific). After blocking with 5% non-fat milk, the membranes were incubated at 4°C overnight with primary antibodies against TLR4 (ab13556, 1:1000, Abcam), NF-κB (ab32536, 1:1000, Abcam), GAPDH (ab9485, 1:2500, Abcam) followed by incubation with the secondary antibody (ab7090, Abcam) for 2 h at room temperature. Lastly, protein bands were visualized with an ECL detection kit (Bio-Rad, Hercules, CA, USA) and quantified with Image Lab software (Bio-Rad).

Real Time Quantitative Polymerase Chain Reaction (RT-qPCR)

Total RNA was extracted from murine nasal mucosa using TRIzol reagent (Invitrogen, Carlsbad, CA, USA). Approximately 1 μg of total RNA was reverse transcribed into cDNA using iScript cDNA kit (Bio-Rad). RT-qPCR was then performed using SYBR Green qPCR Master Mix (DBI® Bioscience, Shanghai, China) on an ABI7300 real-time PCR system (Applied Biosystems, Foster City, CA, USA). The relative gene expression of TNF-α and IL-5 was calculated using the 2^−ΔΔCt method, with GAPDH as normalization. Primer sequences are listed as follows:

TNF-α

Forward: 5′-TTCTCATTCCTGCTTGTGG-3′

Reverse: 5′-TTGGGAACTTCTCATCCCT-3′

IL-5

Forward: 5′-AAGCAATGAGACGATGAGG-3′

Reverse: 5′-ATTCTTCAGTATGTCTAGCCC-3′

GAPDH

Forward: 5′-ACTCTTCCACCTTCGATGC-3′

Reverse: 5′-CCGTATTCATTGTCATACCAGG-3′

Statistical Analysis

Data were analyzed with SPSS 21.0 software (IBM, Armonk, NY, USA) and are expressed as the mean ± standard deviation. Student’s t-test was used for difference comparisons between two groups, while analysis of variance (ANOVA) was used for those among multiple groups followed by Tukey’s post hoc analysis. Each experiment was implemented in triplicate. P <0.05 was considered as significant. Detailed data of the study were provided in Supplementary Table 1.

Results

DAP Alleviates Nasal Symptoms in OVA-Treated Mice

First, to test the effect of DAP on the allergic symptoms of AR, the sneezing and rubbing behaviors of mice were observed following OVA intranasal administration. As shown in Figure 1A-B, the number of sneezing and rubbing was markedly elevated in OVA-induced group compared to the control group (PBS). Notably, the frequency of sneezing and rubbing was decreased after administration with DAP or DEX (Figure 1A-B). In comparison to PBS-treated mice, OVA-treated mice displayed marked histopathological changes, including immune cell infiltration and mucus production in nasal mucosa, however, this effect was mitigated by DAP or DEX treatment, as shown by HE staining (Figure 1C). The above results indicate that DAP can mitigate the symptoms of sneezing and rubbing in mice induced by OVA.

DAP Attenuates Inflammatory Response in Mice

DAP was reported to have an anti-inflammatory effect.⁷ Here, we examined whether DAP also had the same effect on AR. As expected, the OVA group exhibited enhanced production of histamine and OVA-specific IgE in murine serum (Figure 2A-B). On the contrary, DAP or DEX treatment significantly decreased the levels of histamine and OVA-specific IgE, in comparison to the OVA group (Figure 2A-B). The similar trend was observed in the levels of proinflammatory cytokines. OVA-induced increase in TNF-α and IL-5 secretion was markedly attenuated by treatment of DAP or DEX (Figure 2C-D). These were further confirmed by the results of RT-qPCR, which displayed that treatment of DAP or DEX markedly abated OVA-induced upregulation of TNF-α and IL-5 mRNA expression (Figure 2E-F). Collectively, DAP can attenuate OVA-induced inflammation in the AR mouse model.

DAP Attenuates Oxidative Stress in Mice

Accumulating evidence has demonstrated that oxidative stress plays a vital role in AR development.²⁶ We examined DAP effect on oxidative stress in OVA-induced AR mouse model. The levels of oxidative stress-associated markers in murine nasal mucosa were assessed. As displayed by the results, levels of MDA and ROS were markedly increased in OVA group, but DAP or DEX treatment was found to suppress the increased levels of MDA and ROS (Figure 3A,3C). Additionally, the level of SOD, an antioxidant, was decreased in OVA group, and compared with the OVA group, DAP- or DEX-treated groups exhibited elevated SOD level (Figure 3B). Consistent with the aforementioned results, detection of MPO, another oxidative stress marker, revealed that treatment of DAP or DEX significantly alleviated OVA-induced increase in MPO level in murine nasal mucosa (Figure 3D). These results suggested that DAP ameliorates OVA-induced oxidative stress in murine nasal mucosa.

DAP Activates Nrf2/HO-1 Signaling and Inactivates TLR4/NF-κB Signaling in AR Mice

To reveal the potential mechanism of DAP in regulating the pathogenesis of AR, we assessed whether DAP has an impact on Nrf2/HO-1 signaling pathway, which was reported to be an anti-oxidation pathway.²⁷ Results from ELISA showed that compared with those in the PBS group, HO-1 and Nrf2 levels in the OVA group were significantly reduced but were increased after DAP or DEX administration (Figure 4A-B), indicating that DAP can promote the activation of Nrf2/HO-1 signaling pathway. Furthermore, the impact of DAP on TLR4/NF-κB signaling was also explored. Western blotting revealed that protein levels of TLR4 and NF-κB were markedly enhanced in nasal mucosa of OVA-induced mice (Figure 4C-D, Supplementary Figure S1). In parallel, DAP or DEX administration downregulated protein expression of TLR4 and NF-κB in AR mice (Figure 4C-D). Th above data indicate that DAP promotes the activation of Nrf2/HO-1 signaling but suppresses the activation of TLR4/NF-κB signaling in nasal mucosa of AR mice.

Discussion

AR is caused by allergen exposure which leads to IgE-mediated inflammatory response in nasal mucosa.²⁸ AR is a global health issue which results in bad influence on work, sleep and school, and outdoor activities.²⁸ Despite the available treatments, the effects are far from satisfactory and a complete cure for AR is still unavailable.^2,28 Thus, it is of great necessity to identify novel effective drugs for AR.

Emerging evidence has demonstrated that many natural products including coumarins exert a variety of pharmacological effects on the treatment of inflammatory disorders.²⁹ DAP is a coumarin derivative which has been clinically used as a traditional Chinese medicine for the treatment of several diseases, such as coagulopathy and rheumatoid arthritis.³⁰ Moreover, DAP was reported to have antioxidant and anti-inflammatory effects.^10,12 In this study, we established an AR mouse model by OVA induction for detecting the function of DAP in AR. It was found that DAP treatment significantly ameliorated the nasal allergic symptoms in OVA-induced mice, which was reflected by reduced frequency of sneezing and rubbing behaviors. Additionally, this was confirmed by the results from histopathological observation of murine nasal mucosa tissues. DAP treatment markedly alleviated OVA-induced pathological alterations of murine nasal mucosa, including reducing inflammatory cell infiltration and mucus secretion. Furthermore, to validate our results, we used DEX as a positive control for our study which has been confirmed to be effective on inhibiting nose rubbing, sneezing, and nasal discharge as well as attenuating allergic inflammation.³¹ The results revealed that DAP had a similar effect as DEX on symptoms related to AR.

Antihistamine is one of the current treatments for AR.³² Here, we found that DAP could attenuate histamine level in OVA-challenged AR mice, indicating the potential of DAP as an antihistamine drug. Furthermore, the results of this study revealed that DAP also alleviated the production of allergen-specific IgE and proinflammatory cytokines (TNF-α and IL-5). These cytokines-triggered nasal inflammation is closely related to AR. The results indicated the anti-inflammatory role of DAP in AR. Furthermore, increasing evidence has demonstrated that ROS overproduction-induced oxidative stress plays an indispensable role in the pathogenesis of AR.³³ MDA is a product of ROS-mediated oxidative reaction and is considered as a biomarker of oxidative stress.³⁴ SOD is an enzymatic antioxidant involved in the antioxidant defense mechanism.²⁶ MPO is a peroxidase enzyme that catalyzes the conversion of hydrogen peroxide and chloride ions to release more cytotoxic hypochlorite and other chlorinated species, consequently inducing oxidative stress. Additionally, oxidative stress contributes to inflammation, further promoting disease progression.³⁵ Previous studies have indicated the antioxidant role of DAP in several disorders, such as renal injury and diabetic nephropathy.^11,36 In the study, DAP treatment inhibited the levels of oxidative stress markers ROS, MDA, and MPO, but promoted antioxidant SOD activity, elucidating that DAP could attenuate oxidative stress in AR.

Nrf2 is a transcription factor that interacts with its downstream molecule HO-1, consequently triggering the antioxidant effect of HO-1.¹⁹ Additionally, HO-1 was indicated to restrain the secretion of proinflammatory cytokines.¹⁹ DAP activates Nrf2/HO-1 signaling to protect against cisplatin-induced nephrotoxicity.¹² DAP alleviates oxidative stress in hippocampal neurons by activating Nrf2/HO-1 signaling pathway.³⁷ Here, DAP upregulated expression of Nrf2 and HO-1 in AR mice, suggesting that DAP could promote the activation of Nrf2/HO-1 signaling. Additionally, to have a better understanding of DAP-mediated regulation of AR, we also tested its impact on TLR4/NF-κB signaling pathway. Plentiful studies have illustrated that TLR4/ NF-κB signaling pathway exerts a proinflammatory role and is implicated in the development of AR.^18,20,38 Currently, it was disclosed that DAP treatment significantly suppressed the activation of TLR4/NF-κB signaling in OVA-induced nasal mucosa of mice. The inhibitory effect of DAP on TLR4/NF-κB signaling activation was consistent with the previous study ,²¹ confirming the anti-AR effect of DAP.

In conclusion, we examined the function and potential mechanism of DAP in an OVA-induced murine model for AR. The results revealed that DAP treatment ameliorates nasal allergic symptoms, inflammatory response and oxidative stress in AR mice by activating Nrf2/HO-1 signaling and inactivating TLR4/NF-κB signaling. The findings might provide a novel and credible drug for the treatment of AR. However, we only detected the effect of DAP in AR at a dose of 5 mg/kg. Further investigations are needed to test whether there is a dose-dependent response. Additionally, the underlying mechanisms of DAP-mediated protection in AR also need further research.

Supplemental Material

sj-docx-1-ajr-10.1177_19458924221124363 - Supplemental material for Daphnetin Mitigates Ovalbumin-Induced Allergic Rhinitis in Mice by Regulating Nrf2/HO-1 and TLR4/NF-kB Signaling

Supplemental material, sj-docx-1-ajr-10.1177_19458924221124363 for Daphnetin Mitigates Ovalbumin-Induced Allergic Rhinitis in Mice by Regulating Nrf2/HO-1 and TLR4/NF-kB Signaling by Bo Tian, Xin Ma and Rui Jiang in American Journal of Rhinology & Allergy

Supplemental Material

sj-tif-2-ajr-10.1177_19458924221124363 - Supplemental material for Daphnetin Mitigates Ovalbumin-Induced Allergic Rhinitis in Mice by Regulating Nrf2/HO-1 and TLR4/NF-kB Signaling

Supplemental material, sj-tif-2-ajr-10.1177_19458924221124363 for Daphnetin Mitigates Ovalbumin-Induced Allergic Rhinitis in Mice by Regulating Nrf2/HO-1 and TLR4/NF-kB Signaling by Bo Tian, Xin Ma and Rui Jiang in American Journal of Rhinology & Allergy

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article

Ethical Approval

All animal experiments were performed following the Guide for Care and Use of Laboratory Animals and approved by the Animal Research Ethics Committee of Wuhan Hualianke Biotechnology Co., Ltd (approval number: 202108133).

ORCID iD

Rui Jiang

Supplemental material

Supplemental material for this article is available online.

References

Liu

Zhou

, et al. TAK-242 ameliorates olfactory dysfunction in a mouse model of allergic rhinitis by inhibiting neuroinflammation in the olfactory bulb. Int Immunopharmacol. 2021;92(2):107368.

Choi

Jung

Hwang

, et al. Anti-allergic effects of Asarum heterotropoides on an ovalbumin-induced allergic rhinitis murine model. Biomed Pharmacother. 2021;141(4):111944.

Hemmati

Rahimi

Dabiri

, et al. Inhibition of ovalbumin-induced allergic rhinitis by sumatriptan through the nitric oxide pathway in mice. Life Sci. 2019;236(3):116901.

Tang

Peng

, et al. Effects of lentivirus-mediated CCR3 RNA interference on the function of mast cells of allergic rhinitis in mice. Int Immunopharmacol. 2020;78:106011.

Shi

Jiang

Chen

, et al. Chlorogenic acid ameliorated allergic rhinitis-related symptoms in mice by regulating Th17 cells. Biosci Rep. 2020;40(11):BSR20201643.

Pei

Zhang

, et al. Daphnetin exerts an anticancer effect by attenuating the pro-inflammatory cytokines. J Biochem Mol Toxicol. 2021;35(6):1–8.

Singh

Bhatti

. Mechanistic interplay of various mediators involved in mediating the neuroprotective effect of daphnetin. Pharmacol Rep. 2021;73(5):1220–1229.

Zhang

, et al. Anti-inflammatory and protective properties of daphnetin in endotoxin-induced lung injury. J Agric Food Chem. 2014;62(51):12315–12325.

Song

Jiang

Zhang

, et al. Immunosuppressive activity of daphnetin on the humoral immune responses in ovalbumin-sensitized BALB/c mice. Immunopharmacol Immunotoxicol. 2021;43(2):171–175.

10.

Gao

Chen

Fang

, et al. Daphnetin inhibits proliferation and inflammatory response in human HaCaT keratinocytes and ameliorates imiquimod-induced psoriasis-like skin lesion in mice. Biol Res. 2020;53(1):48.

11.

Guo

, et al. Daphnetin inhibits high glucose-induced extracellular matrix accumulation, oxidative stress and inflammation in human glomerular mesangial cells. J Pharmacol Sci. 2019;139(2):91–97.

12.

Zhang

, et al. Daphnetin protects against cisplatin-induced nephrotoxicity by inhibiting inflammatory and oxidative response. Int Immunopharmacol. 2018;65:402–407.

13.

Jin

Zhang

. Total glucosides of paeony ameliorates oxidative stress, apoptosis and inflammatory response by regulating the Smad7-TGF-β pathway in allergic rhinitis. Mol Med Rep. 2022;25(3):83.

14.

Raghav

. Ajwain oil attenuates allergic response of ovalbumin-induced allergic rhinitis via alteration of inflammatory, oxidative stress, and Th1/Th2 responses. J Food Biochem. 2021;45(12):e13963.

15.

Sim

Lee

Kim

, et al. Oxidative stress in schoolchildren with allergic rhinitis: propensity score matching case-control study. Ann Allergy Asthma Immunol. 2015;115(5):391–395.

16.

Jiang

, et al. Overexpression of Cpg15 alleviates the oxidative stress in neuronal cells via regulating redox enzymes and Nrf2 antioxidative pathway. Neurotox Res. 2022;40(2):365–372.

17.

Leitner

Wenzel

Marshall

, et al. Targeting toll-like receptor 4 to modulate neuroinflammation in central nervous system disorders. Expert Opin Ther Targets. 2019;23(10):865–882.

18.

Liu

Jiang

Han

, et al. MicroRNA-345-5p acts as an anti-inflammatory regulator in experimental allergic rhinitis via the TLR4/NF-κB pathway. Int Immunopharmacol. 2020;86(3):106522.

19.

Van Nguyen

Piao

Fan

, et al. Anti-allergic rhinitis activity of α-lipoic acid via balancing Th17/treg expression and enhancing Nrf2/HO-1 pathway signaling. Sci Rep. 2020;10(1):12528.

20.

Dong

Wang

, et al. Luteolin ameliorates inflammation and Th1/Th2 imbalance via regulating the TLR4/NF-κB pathway in allergic rhinitis rats. Immunopharmacol Immunotoxicol. 2021;43(3):319–327.

21.

Liu

Zhao

, et al. Role of daphnetin in rat severe acute pancreatitis through the regulation of TLR4/NF-[formula: see text]B signaling pathway activation. Am J Chin Med. 2016;44(1):149–163.

22.

Yang

Sheng

Nie

, et al. Daphnetin inhibits spinal glial activation via Nrf2/HO-1/NF-κB signaling pathway and attenuates CFA-induced inflammatory pain. Int Immunopharmacol. 2021;98(1):107882.

23.

Jung

Pyun

, et al. Angelica gigas extract ameliorates allergic rhinitis in an ovalbumin-induced mouse model by inhibiting Th2 cell activation. Phytomedicine. 2021;93:153789.

24.

Shen

Zhou

Wang

, et al. Daphnetin reduces endotoxin lethality in mice and decreases LPS-induced inflammation in Raw264.7 cells via suppressing JAK/STATs activation and ROS production. Inflammation Res. 2017;66(7):579–589.

25.

Shi

Chen

, et al. Daphnetin inhibits inflammation in the NZB/W F1 systemic lupus erythematosus murine model via inhibition of NF-κB activity. Exp Ther Med. 2017;13(2):455–460.

26.

Han

Lee

, et al. Oxidative stress and antioxidant pathway in allergic rhinitis. Antioxidants (Basel, Switzerland). 2021;10(8):1266.

27.

Xie

Wang

Zhang

, et al. Design, synthesis and biological evaluation of marine phidianidine-inspired derivatives against oxidized ldl-induced endothelial injury by activating Nrf2 anti-oxidation pathway. Bioorg Chem. 2022;120(7):105606.

28.

Bousquet

Anto

Bachert

, et al. Allergic rhinitis. Nat Rev Dis Primers. 2020;6(1):95.

29.

Fan

Wang

, et al. Daphnetin alleviates lipopolysaccharide/d-galactosamine-induced acute liver failure via the inhibition of NLRP3, MAPK and NF-κB, and the induction of autophagy. Int J Biol Macromol. 2018;119:240–248.

30.

, et al. Daphnetin attenuates LPS-induced osteolysis and RANKL mediated osteoclastogenesis through suppression of ERK and NFATc1 pathways. J Cell Physiol. 2019;234(10):17812–17823.

31.

Dogra

Vijayashankar

. Dexamethasone Suppression Test. StatPearls. StatPearls Publishing LLC.; 2022.

32.

Sun

Qin

Fan

, et al. Chitosan-centered nanosystems as sustained therapeutics for allergic rhinitis intervention: inhibition of histamine-induced cascades. J Controlled Release. 2021;335:422–436.

33.

Wang

Xue

, et al. The protective role of cirsilineol against ovalbumin-induced allergic rhinitis in mice by suppression of inflammation and oxidative stress. J Environ Pathol Toxicol Oncol. 2021;40(3):63–73.

34.

Kohen

Nyska

. Oxidation of biological systems: oxidative stress phenomena, antioxidants, redox reactions, and methods for their quantification. Toxicol Pathol. 2002;30(6):620–650.

35.

Shao

Yuan

Liu

, et al. Epileptic brain fluorescent imaging reveals apigenin can relieve the myeloperoxidase-mediated oxidative stress and inhibit ferroptosis. Proc Natl Acad Sci U S A. 2020;117(19):10155–10164.

36.

Fan

Gao

, et al. Daphnetin ameliorated GM-induced renal injury through the suppression of oxidative stress and apoptosis in mice. Int Immunopharmacol. 2021;96(4):107601.

37.

Zhi

Duan

Pei

, et al. Daphnetin protects hippocampal neurons from oxygen-glucose deprivation-induced injury. J Cell Biochem. 2019;120(3):4132–4139.

38.

Wang

Cui

Liu

, et al. MiR-146a mimic attenuates murine allergic rhinitis by downregulating TLR4/TRAF6/NF-κB pathway. Immunotherapy. 2019;11(13):1095–1105.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.02 MB

0.20 MB