OBJECTIVE To investigate the therapeutic effect and mechanism of Qiwei dongqingye powder （QDP） on bronchial asthma in mice. METHODS The mice were divided into blank group （normal saline）， model group （normal saline）， dexamethasone group （2 mg/kg）， and QDP low-， medium-， and high-dose groups （200， 400， 800 mg/kg）， with 14 mice in each group. Except for the blank group， mice in all other groups were given ovalbumin via intraperitoneal injection followed by aerosol inhalation to induce a bronchial asthma model. During the modeling process， mice in each group were administered corresponding drug solutions or normal saline intragastrically/intraperitoneally. After the last medication， the number of cells in the bronchoalveolar lavage fluid （BALF） of the mice was observed and counted； the pathological changes of the bronchus and lung tissue were observed； the levels of malondialdehyde （MDA）， nitric oxide （NO）， total superoxide dismutase （T-SOD）， and glutathione peroxidase （GSH-Px） in the lung tissue of the mice were determined， and the level of interleukin-17 （IL-17） in the BALF and serum was determined. Transcriptomics was employed to predict and validate the mechanism of action of QDP against bronchial asthma. RESULTS Compared with the model group， the total cell count， neutrophil count， lymphocyte count， and macrophage counts in the BALF of the QDP high-dose group were all significantly reduced （ P ＜0.05）； the levels of MDA and NO in the lung tissue， and the levels of IL-17 in the BALF and serum were all decreased significantly （ P ＜0.05）； the levels of T-SOD and GSH-Px were significantly increased （ P ＜0.05）； the arrangement of lung tissue cells tended to normalize， with reduced infiltration of inflammatory cells and decreased exfoliation of bronchial simple columnar epithelial cells. The transcriptomic results revealed that the differentially expressed genes were B-cell receptor signaling pathway， nuclear factor κB （NF-κB） signaling pathway， ferroptosis signaling pathway， and others. Further validation revealed that， compared with the model group， the expression levels of NF-κB p65 and chemokine ligand 20， as well as the phosphorylation level of NF-κB inhibitor protein α， were significantly decreased in the lung tissues of the mice in all QDP groups （ P ＜0.05）. Conversely， the protein expression of nuclear factor erythroid 2-related factor 2 （Nrf2） and heme oxygenase 1 （HO-1） were significantly increased （ P ＜0.05）. CONCLUSIONS QDP can effectively alleviate bronchial asthma by inhibiting the NF-κB signaling pathway， activating the Nrf2/HO-1 signaling pathway， regulating oxidative stress， and reducing inflammatory responses.

ObjectiveTo explore the efficacy and mechanism of Euphorbia humifusa on acute kidney injury （AKI） based on network pharmacology， molecular docking and experimental verification. MethodsThe active components and targets of E. humifusa were retrieved from TCMSP and SwissTargetPrediction database， and the AKI targets were screened by GeneCards and Online Mendelian Inheritance in Man（OMIM） databases. The drug targets and disease targets were intersected to construct a protein-protein interaction network， and the intersection targets were subjected to gene ontology （GO） and Kyoto encyclopedia of genes and genomes （KEGG） enrichment analysis. Discover Studio software was used to verify the molecular docking of key components and core targets. Gentamicin （GM） was used to induce AKI rat model. Control group， model group， verapamil （16 mg·kg^-1） group， E. humifusa extract （18， 54， 162 mg·kg^-1·d^-1） group and E. humifusa 70% ethanol extract （423 mg·kg^-1） group were continuously administered for 14 days. Urine volume was detected 24 h after modeling and administration. Serum creatinine （SCr）， Blood urea nitrogen （BUN）， 24-hour urine protein （24 hUTP） and uric acid （UA） content； the contents of malondialdehyde （MDA）， glutathione （GSH）， superoxide dismutase （SOD）， carbon monoxide synthase （NOS） and lactate dehydrogenase （LDH） in kidney were measured. The levels of interleukin （IL）-6 and tumor necrosis factor （TNF）-α in serum were detected by enzyme linked immunosorbent assay（ELISA） kit. The pathological changes of renal tissue were detected by hematoxylin-eosin （HE） and Masson staining. Western blot was used to detect the expression of PI3K/protein kinase B（Akt）/NF-κB signaling pathway-related proteins. ResultsIn this study， 13 active components such as kaempferol， luteolin， apigenin， gallic acid and quercetin were screened and identified from E. humifusa. Through bioinformatics analysis， these components and AKI have a total of 289 targets， of which 62 are core targets， including Akt1， TNF， tumor protein p53（TP53） and IL-1β. These targets are mainly involved in the regulation of biological processes such as NF-κB signaling pathway， HIF-1 signaling pathway， TNF signaling pathway， PI3K/Akt signaling pathway and mitogen-activated protein kinase（MAPK） signaling pathway. In animal experiments， we successfully constructed a GM-induced AKI model in rats. Compared with the model group， E. humifusa extract could significantly reduce the levels of 24 hUTP， BUN and SCr in rats （P<0.01）， indicating its improvement effect on renal function. In addition， the extract of E. humifusa also significantly reduced LDH activity and MDA content in rat kidney tissue （P<0.05， P<0.01）， and significantly increased SOD， NOS activity and GSH content （P<0.05）， indicating that the extract of E. humifusa has the potential of anti-oxidation and protection of renal function. Further analysis of inflammatory factors showed that the levels of IL-6 and TNF-α in serum of rats treated with E. humifusa extract were significantly decreased （P<0.01）， indicating that E. humifusa extract had anti-inflammatory effects. In addition， the extract of E. humifusa can also regulate the protein expression of PI3K/Akt/NF-κB signaling pathway， which further confirmed its mechanism of reducing GM-induced AKI. ConclusionThe extract of E. humifusa has a significant therapeutic effect on acute kidney injury through its multi-component and multi-target mechanism. Its effect is reflected in improving renal function， anti-oxidation， anti-inflammation and regulating immune response. These findings provide a scientific basis for the application of E. humifusa in the treatment of acute kidney injury， and point out the direction for future drug development and clinical research.

ObjectiveTo explore the potential mechanism of Dingchuan Granule （定喘颗粒， DG） in the treatment of respiratory syncytial virus （RSV） pneumonia. MethodsA total of 60 male Sprague Dawley （SD） rats were randomly divided into control group， model group， ribavirin group， DG low-dose group， DG middle-dose group， and DG high-dose group， with 10 rats in each group. Except for the control group， rats were administrated with RSV via intranasal drip. After model establishment， the DG low-， middle-， and high-dose groups were administrated via oral gavage with DG at 3.47， 6.93， and 13.86 g/（kg·d） respectively， while the ribavirin group was administrated via oral gavage with ribavirin at 15.75 mg/（kg·d）. The drug was given once daily for one week. The rats in the control group and the model group were not given any drug， only subjected to the grasping action. Twenty-four hours after the last administration， the pathological changes of lung tissues were observed and scored using HE staining. The levels of serum inflammatory factors， including tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）， and interleukin-6 （IL-6）， were detected by colorimetry. The protein levels of nuclear factor （erythroid derived 2）-like 2 （Nrf2）， Kelch-like ECH-associated protein 1 （Keap1）， heme oxygenase 1 （HO-1）， and NAD（P）H quinone dehydrogenase 1 （NQO1） in lung tissues were measured by Western Blot. The RSV load as well as the gene expression levels of Nrf2， Keap1， HO-1， and NQO1 in lung tissues were determined by qRT-PCR. The level of reactive oxygen species （ROS） in rat lung tissues was detected using chemiluminescence. The levels of glutathione （GSH） and malondialdehyde （MDA） in rat lung tissues were measured by a microassay. ResultsCompared with the control group， other groups had significant increases in pathological score of lung tissue， RSV load， levels of ROS， MDA， serum TNF-α， IL-1β， and IL-6； decrease in GSH level， increases in expression level of Keap1 protein and its mRNA in lung tissue， and significant decrease in levels of Nrf2， HO-1， expression level of NQO1 protein and its mRNA （P＜0.05）. Compared with the model group， all the above-mentioned indicators in the DG low-， middle-， and high-dose groups and the ribavirin group were improved to varying degree （P＜0.05）. The levels of serum TNF-α， IL-1β， and IL-6 in rats of DG dose groups showed a dose-dependent pattern， the DG high-dose group exhibiting the best effect （P＜0.05）. The DG high-dose group was superior to the DG low- and middle-dose groups in reducing the levels of ROS and MDA， and increasing the level of GSH in lung tissues （P＜0.05）. The DG high-dose group and the ribavirin group had better effect than the DG middle-dose group in reducing the RSV load （P＜0.05）. The DG high-dose group was superior to the ribavirin group in improving the protein levels of Nrf2， Keap1， HO-1， and NQO1 （P＜0.05）. ConclusionDG could inhibit oxidative stress by regulating the Nrf2/Keap1/HO-1/NQO1 signaling pathway to improve pulmonary inflammation and treat RSV pneumonia， with the DG high-dose group showing the best effect.

Objective:To investigate the anti-fatigue effect of Dendrobium and Panax Quinquefolius Granules(DPQG)on the overtrained mice,and to clarify its possible mechanism.Methods:A total of 48 mice were randomly divided into control group(equal volume of distilled water),low dose of DPQG group(400 mg·kg-1 DPQG),medium dose of DPQG group(800 mg·kg-1 DPQG),and high dose of DPQG group(1 600 mg·kg-1 DPQG).The DPQG were administered by gavage for 35 d,and the rotarod test and swimming endurance test were performed 30 min after last administration.Serum,liver tissue,and muscle tissue were collected from the mice in various groups.ELISA method was used to detect the serum lacticacid(LAC)levels and lactate dehydrogenase(LDH)activities,and the malondialdehyde(MDA)levels,superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)activities,and the liver glycogen and muscle glycogen levels in muscle tissue of the mice in various groups;HE staining was used to observe the pathomorphology of muscle tissue of the mice.Transcriptomics and metabolomics technologies were used to identify the key genes and metabolites in muscle tissue of the mice in control group and high dose of DPQG group and to analyze the correlations between differentially expressed genes(DEGs)and differentially expressed metabolites.Results:Compared with control group,the rod turning exhaustion time of the mice in different doses of DPQG groups were significantly increased(P＜0.05),and the swimming exhaution time of the mice in high dose of DPQG group was increased(P＜0.05).Compared with control group,the LDH,SOD,and GSH-Px activities of the mice in medium and high doses of DPQG groups were increased(P＜0.01).Compared with control group,the levels of MDA and liver glycogen of the mice in medium and high doses of DPQG groups were decreased(P＜0.05 or P＜0.01).The transcriptomics sequencing results showed that DPQG mainly acted on DEGs such as Trib3 and Olfr495;the Gene Ontology(GO)functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)signaling pathway enrichment analysis results showed that the DEGs were mainly enriched in olfactory-related processes and signaling pathways;the metabolomics KEGG analysis results showed that the differential metabolites were mainly enriched in the regulation pathway of inflammatory mediators on tryptophan(TRP);the combined analysis of transcriptomics and metabolomics results showed that the piezo1 gene had high correlations with the differential metabolites β1-solamarine(r=-1,P＜0.05)and tilidine(r=1,P＜0.05).Conclusion:DPQG can exert an anti-fatigue effect on the overtrained mice by modulating LAC metabolism and glycogen homeostasis,as well as maintaining the oxidative/antioxidant balance in the body;its anti-fatigue mechanism is related to the Olfr495 and piezo1 genes and the regulation pathway of inflammatory mediators on TRP channels.

ObjectiveTo improve the therapeutic effect of Buyang Huanwutang（BYHW） on diabetic kidney disease （DKD） and explore new methods for developing new Chinese medicine decoctions，we utilized 5-hydroxymethylcytosine （5hmC）-Seal sequencing technology and network pharmacology to modify BYHW. MethodsWe selected 14 diabetes mellitus （DM） patients and 15 DKD patients hospitalized in the Department of Endocrinology of Peking University Third Hospital in 2021. Circulating free DNA （cfDNA） in the patients’ plasma was sequenced. After data processing and screening， we performed temporal clustering analysis to select a DKD 5hmC gene set， which was then cross-validated with a DKD database gene set to obtain the DKD gene set. We retrieved target genes of the seven herbal components of BYHW from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform （TCMSP） and the Encyclopedia of Traditional Chinese Medicine （ETCM）， and performed cross-analysis with the DKD gene set to identify common genes shared by the disease and the Chinese medicines. A protein-protein interaction （PPI） network was constructed for the common genes to screen out the key genes. Chinese medicines targeting these key genes were searched against ETCM to identify removable Chinese medicines. Kyoto Encyclopedia of Genes and Genomes （KEGG） enrichment analysis was performed on non-common DKD genes， and key genes in DKD-related pathways were selected based on machine learning. The GSE30529 dataset was used to verify the expression trends of 5hmC-modified genes and the feasibility of target genes as drug targets. TCMBank was used to search for target genes and obtain compounds targeting these genes and the corresponding Chinese medicines to construct a "key target-compound-Chinese medicine" network. Molecular docking was employed to verify the binding affinity of compounds with key targets. TCMSP and ETCM were used to search and count the candidate Chinese medicines targeting DKD-related genes， and a new decoction was formed by adding the selected Chinese medicines. A mouse model of DKD was established to examine the efficacy of the new decoction based on the mouse body mass， random blood glucose， urinary microalbumin （mALB）， serum creatinine （Scr）， and blood urea nitrogen （BUN） and by hematoxylin-eosin staining， periodic acid-Schiff staining， Masson staining， immunofluorescence assay， and Real-time PCR. ResultsThe cross-analysis results showed that the DKD gene set included 507 genes， of which 30 were target genes of BYHW. The PPI analysis indicated that the top 15% target genes regarding the degree were interleukin-6 （IL-6）， Toll-like receptor 4 （TLR4）， lactotransferrin （LTF）， lipoprotein lipase （LPL）， and sterol regulatory element-binding transcription factor 1 （SREBF1）. Persicae Semen and Pheretima in BYHW were unrelated to key genes and removed. Machine learning identified 10 potential target genes， among which TBC1 domain family member 5 （TBC1D5）， RAD51 paralog B （RAD51B）， and proteasome 20S subunit alpha 6 （PSMA6） had expression trends consistent with the GSE30529 dataset and could serve as drug targets. The "key target-compound-Chinese medicine" network and molecular docking results indicated that the compounds with good binding affinity to target proteins were arginine， glycine， myristicin， serine， and tyrosine， corresponding to 121 Chinese medicines. The top 10 Chinese medicines targeting DKD-related genes were Lycii Fructus， Ginseng Radix et Rhizoma， Dioscoreae Rhizoma， Rehmanniae Radix Praeparata， Isatidis Radix， Glehniae Radix， Ophiopogonis Radix， Allii Sativi Bulbus， Isatidis Folium， and Bolbostemmatis Rhizoma. Based on traditional Chinese medicine theory， the new decoction was obtained after removal of Persicae Semen and Pheretima and addition of Rehmanniae Radix Praeparata and Dioscoreae Rhizoma. Animal experiment results indicated that the modified BYHW improved the kidney function and inhibited renal fibrosis in DKD mice， with better effects than the original decoction. ConclusionThe BYHW modified based on 5hmC-Seal sequencing demonstrates better performance in inhibiting fibrosis and ameliorating DKD than the original decoction. This elucidates the biomedical theory behind the epigenetic modification of traditional Chinese medicine prescriptions， potentially offering new perspectives for the exploration of these prescriptions

ObjectiveTo improve the therapeutic effect of Buyang Huanwutang（BYHW） on diabetic kidney disease （DKD） and explore new methods for developing new Chinese medicine decoctions，we utilized 5-hydroxymethylcytosine （5hmC）-Seal sequencing technology and network pharmacology to modify BYHW. MethodsWe selected 14 diabetes mellitus （DM） patients and 15 DKD patients hospitalized in the Department of Endocrinology of Peking University Third Hospital in 2021. Circulating free DNA （cfDNA） in the patients’ plasma was sequenced. After data processing and screening， we performed temporal clustering analysis to select a DKD 5hmC gene set， which was then cross-validated with a DKD database gene set to obtain the DKD gene set. We retrieved target genes of the seven herbal components of BYHW from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform （TCMSP） and the Encyclopedia of Traditional Chinese Medicine （ETCM）， and performed cross-analysis with the DKD gene set to identify common genes shared by the disease and the Chinese medicines. A protein-protein interaction （PPI） network was constructed for the common genes to screen out the key genes. Chinese medicines targeting these key genes were searched against ETCM to identify removable Chinese medicines. Kyoto Encyclopedia of Genes and Genomes （KEGG） enrichment analysis was performed on non-common DKD genes， and key genes in DKD-related pathways were selected based on machine learning. The GSE30529 dataset was used to verify the expression trends of 5hmC-modified genes and the feasibility of target genes as drug targets. TCMBank was used to search for target genes and obtain compounds targeting these genes and the corresponding Chinese medicines to construct a "key target-compound-Chinese medicine" network. Molecular docking was employed to verify the binding affinity of compounds with key targets. TCMSP and ETCM were used to search and count the candidate Chinese medicines targeting DKD-related genes， and a new decoction was formed by adding the selected Chinese medicines. A mouse model of DKD was established to examine the efficacy of the new decoction based on the mouse body mass， random blood glucose， urinary microalbumin （mALB）， serum creatinine （Scr）， and blood urea nitrogen （BUN） and by hematoxylin-eosin staining， periodic acid-Schiff staining， Masson staining， immunofluorescence assay， and Real-time PCR. ResultsThe cross-analysis results showed that the DKD gene set included 507 genes， of which 30 were target genes of BYHW. The PPI analysis indicated that the top 15% target genes regarding the degree were interleukin-6 （IL-6）， Toll-like receptor 4 （TLR4）， lactotransferrin （LTF）， lipoprotein lipase （LPL）， and sterol regulatory element-binding transcription factor 1 （SREBF1）. Persicae Semen and Pheretima in BYHW were unrelated to key genes and removed. Machine learning identified 10 potential target genes， among which TBC1 domain family member 5 （TBC1D5）， RAD51 paralog B （RAD51B）， and proteasome 20S subunit alpha 6 （PSMA6） had expression trends consistent with the GSE30529 dataset and could serve as drug targets. The "key target-compound-Chinese medicine" network and molecular docking results indicated that the compounds with good binding affinity to target proteins were arginine， glycine， myristicin， serine， and tyrosine， corresponding to 121 Chinese medicines. The top 10 Chinese medicines targeting DKD-related genes were Lycii Fructus， Ginseng Radix et Rhizoma， Dioscoreae Rhizoma， Rehmanniae Radix Praeparata， Isatidis Radix， Glehniae Radix， Ophiopogonis Radix， Allii Sativi Bulbus， Isatidis Folium， and Bolbostemmatis Rhizoma. Based on traditional Chinese medicine theory， the new decoction was obtained after removal of Persicae Semen and Pheretima and addition of Rehmanniae Radix Praeparata and Dioscoreae Rhizoma. Animal experiment results indicated that the modified BYHW improved the kidney function and inhibited renal fibrosis in DKD mice， with better effects than the original decoction. ConclusionThe BYHW modified based on 5hmC-Seal sequencing demonstrates better performance in inhibiting fibrosis and ameliorating DKD than the original decoction. This elucidates the biomedical theory behind the epigenetic modification of traditional Chinese medicine prescriptions， potentially offering new perspectives for the exploration of these prescriptions

Macrophages are innate immune cells connected with the development of inflammation. Retinoic acid has previously been proved to have anti-inflammatory and anti-arthritic properties. However, the exact mechanism through which retinoic acid modulates arthritis remains unclear. This study aimed to investigate whether retinoic acid ameliorates rheumatoid arthritis by modulating macrophage polarization. This study used retinoic acid to treat mice with adjuvant arthritis and evaluated anti-inflammatory effects by arthritis score, thermal nociceptive sensitization test, histopathologic examination and immunofluorescence assays. In addition, its specific anti-arthritic mechanism was investigated by flow cytometry, cell transfection and inflammatory signaling pathway assays in RAW264.7 macrophages in vitro. Retinoic acid significantly relieved joint pain and attenuated inflammatory cell infiltration in mice. Furthermore, this treatment modulated peritoneal macrophage polarization, increased levels of arginase 1, as well as decreased inducible nitric oxide synthase expression. In vitro, we verified that retinoic acid promotes macrophage transition from the M1 to M2 type by upregulating mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) expression and inhibiting P38, JNK and ERK phosphorylation in lipopolysaccharide-stimulated RAW264.7 cells. Notably, the therapeutic effects of retinoic acid were inhibited by MKP-1 knockdown. Retinoic acid exerts a significant therapeutic effect on adjuvant arthritis in mice by regulating macrophage polarization through the MKP-1/MAPK pathway, and play an important role in the treatment of rheumatic diseases.

Macrophages are innate immune cells connected with the development of inflammation. Retinoic acid has previously been proved to have anti-inflammatory and anti-arthritic properties. However, the exact mechanism through which retinoic acid modulates arthritis remains unclear. This study aimed to investigate whether retinoic acid ameliorates rheumatoid arthritis by modulating macrophage polarization. This study used retinoic acid to treat mice with adjuvant arthritis and evaluated anti-inflammatory effects by arthritis score, thermal nociceptive sensitization test, histopathologic examination and immunofluorescence assays. In addition, its specific anti-arthritic mechanism was investigated by flow cytometry, cell transfection and inflammatory signaling pathway assays in RAW264.7 macrophages in vitro. Retinoic acid significantly relieved joint pain and attenuated inflammatory cell infiltration in mice. Furthermore, this treatment modulated peritoneal macrophage polarization, increased levels of arginase 1, as well as decreased inducible nitric oxide synthase expression. In vitro, we verified that retinoic acid promotes macrophage transition from the M1 to M2 type by upregulating mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) expression and inhibiting P38, JNK and ERK phosphorylation in lipopolysaccharide-stimulated RAW264.7 cells. Notably, the therapeutic effects of retinoic acid were inhibited by MKP-1 knockdown. Retinoic acid exerts a significant therapeutic effect on adjuvant arthritis in mice by regulating macrophage polarization through the MKP-1/MAPK pathway, and play an important role in the treatment of rheumatic diseases.

Macrophages are innate immune cells connected with the development of inflammation. Retinoic acid has previously been proved to have anti-inflammatory and anti-arthritic properties. However, the exact mechanism through which retinoic acid modulates arthritis remains unclear. This study aimed to investigate whether retinoic acid ameliorates rheumatoid arthritis by modulating macrophage polarization. This study used retinoic acid to treat mice with adjuvant arthritis and evaluated anti-inflammatory effects by arthritis score, thermal nociceptive sensitization test, histopathologic examination and immunofluorescence assays. In addition, its specific anti-arthritic mechanism was investigated by flow cytometry, cell transfection and inflammatory signaling pathway assays in RAW264.7 macrophages in vitro. Retinoic acid significantly relieved joint pain and attenuated inflammatory cell infiltration in mice. Furthermore, this treatment modulated peritoneal macrophage polarization, increased levels of arginase 1, as well as decreased inducible nitric oxide synthase expression. In vitro, we verified that retinoic acid promotes macrophage transition from the M1 to M2 type by upregulating mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) expression and inhibiting P38, JNK and ERK phosphorylation in lipopolysaccharide-stimulated RAW264.7 cells. Notably, the therapeutic effects of retinoic acid were inhibited by MKP-1 knockdown. Retinoic acid exerts a significant therapeutic effect on adjuvant arthritis in mice by regulating macrophage polarization through the MKP-1/MAPK pathway, and play an important role in the treatment of rheumatic diseases.

Macrophages are innate immune cells connected with the development of inflammation. Retinoic acid has previously been proved to have anti-inflammatory and anti-arthritic properties. However, the exact mechanism through which retinoic acid modulates arthritis remains unclear. This study aimed to investigate whether retinoic acid ameliorates rheumatoid arthritis by modulating macrophage polarization. This study used retinoic acid to treat mice with adjuvant arthritis and evaluated anti-inflammatory effects by arthritis score, thermal nociceptive sensitization test, histopathologic examination and immunofluorescence assays. In addition, its specific anti-arthritic mechanism was investigated by flow cytometry, cell transfection and inflammatory signaling pathway assays in RAW264.7 macrophages in vitro. Retinoic acid significantly relieved joint pain and attenuated inflammatory cell infiltration in mice. Furthermore, this treatment modulated peritoneal macrophage polarization, increased levels of arginase 1, as well as decreased inducible nitric oxide synthase expression. In vitro, we verified that retinoic acid promotes macrophage transition from the M1 to M2 type by upregulating mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) expression and inhibiting P38, JNK and ERK phosphorylation in lipopolysaccharide-stimulated RAW264.7 cells. Notably, the therapeutic effects of retinoic acid were inhibited by MKP-1 knockdown. Retinoic acid exerts a significant therapeutic effect on adjuvant arthritis in mice by regulating macrophage polarization through the MKP-1/MAPK pathway, and play an important role in the treatment of rheumatic diseases.