Asiaticoside conveys an antifibrotic effect by inhibiting activation of hepatic stellate cells via the Jagged-1/Notch-1 pathway.

The aim of this study was to investigate the underlying protective mechanisms of asiaticoside (AS) against liver fibrosis (LF) both in vivo and in vitro. A rat model with carbon tetrachloride (CCl4)-induced liver fibrosis is employed to verify the effect and mechanism of AS on the process of liver fibrosis in vivo experiment. Hematoxylin/eosin and sirius red staining was conducted to assess the severity of liver injury and fibrosis. Further, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (ALB), glutamyl transferase (GGT), and total bilirubin (TBil) were measured. In addition, LX2 cells were cultured for vitro experiment to investigate the influence of AS on hepatic stellate cells (HSCs). Overproduction of α-smooth muscle actin and type I collagen is characteristic of LF and HSCs, as determined by immunohistochemical and Western blot analyses. The expression levels of molecules associated with the Notch signaling pathway (i.e., Notch-1, Jagged-1, and Delta-like-4) were assessed by Western blot analysis. The results revealed that AS attenuated LF, as defined by reduced deposition of collagen, expression of α-smooth muscle actin and collagen type 1, and expression of biochemical parameters (alanine aminotransferase, aspartate aminotransferase, and hydroxyproline). Notably, AS suppressed the expression levels of Notch-1, Jagged-1, and Delta-like-4 in activated HSCs and LF. Collectively, these results demonstrate that AS prevented the progression of LF by modulating the Notch signaling pathway, indicating that AS has potential therapeutic effects against LF.

Xiaotansanjiefang inhibits the viability of colorectal cancer cells via Jagged 1/Notch 3/Snail signaling pathway.

The purpose of this study is to explore the anti-colorectal cancer of Xiaotansanjiefang, a famous traditional Chinese medicine, and its potential anti-cancer mechanism. In this study, the HCT116 cell spheres were prepared as in vitro study model. We found the Xiaotansanjiefang medication was able to inhibit the proliferation of HCT116 cell spheres in a dose-dependent manner, especially in 3 and 6 mg/ml Xiaotansanjiefang medication treated groups. We also found the high concentration of Xiaotansanjiefang medication could suppress the migration and promote the apoptosis of HCT116 cell spheres. Moreover, we found the expression of Jagged 1, Notch 3, Snail, and Hes 1 were decreased in HCT116 cell spheres treated with Xiaotansanjiefang medication. Furthermore, the proliferation and apoptosis behaviors of HCT116 cell spheres treated with Xiaotansanjiefang medication were reversed with the addition of Jagged 1 Fc chimera protein. The expression of Jagged 1, Notch 3, Snail, and Hes 1 were also increased again in HCT116 cells treated with Xiaotansanjiefang medication plus with Jagged 1 Fc chimera protein. The presented study may provide a promising strategy to treat and prevent colorectal cancer.

Effect of Danggui-Shaoyao-San-Containing Serum on the Renal Tubular Epithelial-Mesenchymal Transition of Diabetic Nephropathy.

OBJECTIVES: To investigate the effect of Danggui-Shaoyao-San (DSS)-containing serum on the renal tubular Epithelial-Mesenchymal Transition (EMT) of Diabetic Nephropathy (DN) in high glucose- induced HK-2 cells and its mechanism. METHODS: 20 rats were randomly divided into four groups: blank control group, DSS low dose group (DSS-L), DSS middle dose group (DSS-M), and DSS high dose group (DSS-H). DSS was administrated to the corresponding group (7g/kg/d, 14g/kg/d and 21g/kg/d) for 7 consecutive days, and the same volume of saline was given to the blank control group by gavage. The rat drug-containing serum was successfully prepared. HK-2 cells were divided into five groups: blank control group, model group, DSS-L, DSS-M, DSS-H, according to the corresponding drug and dose of each treatment group. Protein and mRNA levels of Jagged1, Notch1, Hes5, Notch Intracellular Domain (NICD), E-cadherin, alpha- Smooth Muscle Actin (α-SMA) and vimentin at 24h, 48h and 72h were detected by Western Blot and RT-qPCR. RESULTS: The protein and mRNA levels of Jagged1, Notch1, Hes5, NICD, α-SMA and vimentin in the treatment groups were remarkably decreased compared with the model group (P<0.05), and the protein and mRNA levels of E-cadherin were notably increased (P<0.05) by Western Blot and RT-qPCR. CONCLUSION: Our results demonstrated that DSS could prevent DN by ameliorating renal tubular EMT through inhibition of the Notch signaling pathway.

Usefulness of melatonin as complementary to chemotherapeutic agents at different stages of the angiogenic process.

Chemotherapeutics are sometimes administered with drugs, like antiangiogenic compounds, to increase their effectiveness. Melatonin exerts antitumoral actions through antiangiogenic actions. We studied if melatonin regulates the response of HUVECs to chemotherapeutics (docetaxel and vinorelbine). The inhibition that these agents exert on some of the processes involved in angiogenesis, such as, cell proliferation, migratory capacity or vessel formation, was enhanced by melatonin. Regarding to estrogen biosynthesis, melatonin impeded the negative effect of vinorelbine, by decreasing the activity and expression of aromatase and sulfatase. Docetaxel and vinorelbine increased the expression of VEGF-A, VEGF-B, VEGF-C, VEGFR-1, VEGFR-3, ANG1 and/or ANG-2 and melatonin inhibited these actions. Besides, melatonin prevented the positive actions that docetaxel exerts on the expression of other factors related to angiogenesis like JAG1, ANPEP, IGF-1, CXCL6, AKT1, ERK1, ERK2, MMP14 and NOS3 and neutralized the stimulating actions of vinorelbine on the expression of FIGF, FGFR3, CXCL6, CCL2, ERK1, ERK2, AKT1, NOS3 and MMP14. In CAM assay melatonin inhibited new vascularization in combination with chemotherapeutics. Melatonin further enhanced the chemotherapeutics-induced inhibition of p-AKT and p-ERK and neutralized the chemotherapeutics-caused stimulatory effect on HUVECs permeability by modifying the distribution of VE cadherin. Our results confirm that melatonin blocks proangiogenic and potentiates antiangiogenic effects induced by docetaxel and vinorelbine enhancing their antitumor effectiveness.

De-Glycyrrhizinated Licorice Extract Attenuates High Glucose-Stimulated Renal Tubular Epithelial-Mesenchymal Transition via Suppressing the Notch2 Signaling Pathway.

Tubulointerstitial fibrosis is a major pathological hallmark of diabetic nephropathy. Increasing evidence has shown that epithelial-to-mesenchymal transition (EMT) of renal proximal tubular cells plays a crucial role in tubulointerstitial fibrosis. Herein, we aimed to elucidate the detailed mechanism of EMT in renal tubular cells under high glucose (HG) conditions, and to investigate the potential of licorice, a medicinal herb, to inhibit HG-induced EMT. Our results showed that renal tubular epithelial cells (normal rat kidney cell clone 52E; NRK-52E) exposed to HG resulted in EMT induction characterized by increased fibronectin and -SMA (alpha-smooth muscle actin) but decreased E-cadherin. Elevated levels of cleaved Notch2, MAML-1 (mastermind-like transcriptional coactivator 1), nicastrin, Jagged-1 and Delta-like 1 were also concomitantly detected in HG-cultured cells. Importantly, pharmacological inhibition, small interfering RNA (siRNA)-mediated depletion or overexpression of the key components of Notch2 signaling in NRK-52E cells supported that the activated Notch2 pathway is essential for tubular EMT. Moreover, we found that licorice extract (LE) with or without glycyrrhizin, one of bioactive components in licorice, effectively blocked HG-triggered EMT in NRK-52E cells, mainly through suppressing the Notch2 pathway. Our findings therefore suggest that Notch2-mediated renal tubular EMT could be a therapeutic target in diabetic nephropathy, and both LE and de-glycyrrhizinated LE could have therapeutic potential to attenuate renal tubular EMT and fibrosis.

Differential effect of grape seed extract and its active constituent procyanidin B2 3,3″-di-O-gallate against prostate cancer stem cells.

The present study aimed to determine whether grape seed extract (GSE) procyanidin mix, and its active constituent procyanidin B2 3,3″-di-O-gallate (B2G2) have the potential to target cancer stem cells (CSCs) in prostate cancer (PCa). The CSC populations were isolated and purified based on CD44+ -α2ß1high surface markers in PCa cell lines LNCaP, C4-2B, 22Rv1, PC3, and DU145, and then subjected to prostasphere formation assays in the absence or presence of GSE or B2G2. Results indicated that at lower doses (<15 µg) , the GSE procyanidin mix produced activity in unsorted prostate cancer antigen (PCA) cells, but not in sorted; however, multiple treatments with low dose GSE over a course of time inhibited sphere formation by sorted PCA CSCs. Importantly, B2G2 demonstrated significant potential to target both unsorted and sorted CSCs at lower doses. As formation of spheroids, under specific in vitro conditions, is a measure of stemness, these results indicated the potential of both GSE and B2G2 to target the self-renewal of CSC in PCa cell lines, though B2G2 was more potent in its efficacy. Subsequent mechanistic studies revealed that both GSE procyanidins and B2G2 strongly decreased the constitutive as well as Jagged1 (Notch1 ligand)-induced activated Notch1 pathway. In totality, these in vitro studies warrant extensive dose-profiling-based assessments in vivo settings to conclusively determine the impact on CSC pool kinetics on the efficacy of both GSE and B2G2 to target PCa growth as well as tumor relapse.

The antitumor function of arctigenin in human retinoblastoma cells is mediated by jagged­1.

Retinoblastoma is an intraocular malignant tumor that may severely affect vision and represents a life­threatening disease in children. Arctigenin (ATG) is an active compound that exhibits numerous pharmacological activities, which is isolated from the seeds of greater burdock (Arctium lappa Linnaeus), a plant used in traditional Chinese herbal medicine. The present study aimed to investigate the effects of ATG on cancer progression by analyzing the retinoblastoma cell line Y79. ATG exhibited a significant inhibitory effect on the viability of Y79 cells in a dose­dependent manner. Furthermore, treatment with ATG promoted apoptosis, and increased the protein expression levels of B­cell lymphoma 2 (BCL­2)­associated X protein and decreased the protein expression levels of BCL­2. Cell migration was suppressed following treatment with ATG, as assessed by Transwell migration assay. Furthermore, the protein expression levels of jagged­1 (JAG1) were decreased, and various factors involved in the Notch signaling pathway, including the Notch intracellular domain (NICD), transcription factor HES (HES)5 and HES1 were downregulated following treatment with ATG. The decreased expression levels of JAG1 were restored in response to JAG1 overexpression, alongside increases in the protein expression levels of NICD, HES5 and HES1. Furthermore, overexpression of JAG1 partly restored the cell viability and migration suppressed following treatment with ATG. In addition, ATG­induced apoptosis was reduced by JAG1 overexpression. Collectively, the present results suggested that ATG may serve as an antitumor compound by suppressing the proliferation and migration of retinoblastoma cells, inducing apoptosis, downregulating the protein expression levels of JAG1, and decreasing the activity of the Notch signaling pathway.

Wenshen Zhuanggu formula mitigates breast cancer bone metastasis through the signaling crosstalk among the Jagged1/Notch, TGF-ß and IL-6 signaling pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Advanced breast cancer frequently metastasizes to the bone, resulting in patient morbidity and mortality. The interaction of tumor cells with osteoclasts and osteoblasts seriously affects the occurrence and development of bone metastasis in breast cancer. The signaling crosstalk among the Jagged1/Notch, TGF-ß and IL-6 signaling pathways plays a significant role in the context of bone metastasis. AIM OF THE STUDY: Although Wenshen Zhuanggu (WSZG) formula efficiently decreased the risk of bone metastases in tumor-bearing mice, it remains unclear how WSZG formula regulates the interaction of cancer cells with osteoclasts and osteoblasts in bone metastasis of breast cancer. MATERIALS AND METHODS: In this study, we investigated the role of WSZG formula in the progress of bone metastasis in breast cancer and focused on the cell-cell interactions of tumor cells with osteoclasts and osteoblasts. Western blotting and quantitative real-time PCR were utilized to evaluate the inhibitory activities of WSZG formula on Jagged1 expression both in vivo and in vitro. Osteoblast co-culture and osteoclastogenesis co-culture were applied to analyze the effects of WSZG formula on the interaction of tumor cells with osteoclasts and osteoblasts. A breast cancer xenograft model was also used to test the inhibitory effects of WSZG formula on bone metastasis in breast cancer. RESULTS: WSZG formula decreased Jagged1 expression in osteolytic lesions in the breast cancer xenograft model. Additionally, WSZG formula decreased Jagged1 expression in tumor cell culture alone or co-culture with pre-osteoclasts and osteoblasts. In addition, WSZG formula decreased Jagged1 expression in Jagged1-overexpressing tumor cells. CONCLUSION: The results of this study suggest that WSZG formula mitigates breast cancer bone metastasis through the Jagged1/Notch signaling pathway mediated by TGF-ß and IL-6.

Effect of dioscin on promoting liver regeneration via activating Notch1/Jagged1 signal pathway.

BACKGROUND: Development of novel candidates to promote liver regeneration is critical important after partial hepatectomy (PH). Dioscin, a natural product, shows potent effect on liver protection in our previous works. PURPOSE: This work aimed to investigate the effect and underlying mechanisms of dioscin on liver regeneration. METHODS: The promoting proliferation effects of dioscin on mouse hepatocytem AML12 cells, rat primary hepatocytes, rats and mice after 70% PH were evaluated. RESULTS: Dioscin significantly promoted proliferation of rat primary hepatocytes and AML12 cells through MTT, BrdU and PCNA staining assays. Meanwhile, dioscin rapidly recovered the liver to body weight ratios, declined ALT and AST levels, and relieved hepatocytes necrosis compared with 70% PH operation groups in rats and mice. Mechanistic test showed that dioscin significantly increased Notch1 and Jagged1 levels, and accelerated γ-secretase activity by up-regulating PS1 expression, leading to nuclear translocation of Notch1 intracellular domain (NICD1). Subsequently, the significant activation of Notch-dependent target genes (Hey1, Hes1, EGFR, VEGF), and cell-cycle regulatory proteins (CyclinD1, CyclinE1, CDK4 and CDK2) were all recognized. In addition, these results were further confirmed by Notch1 siRNA silencing and inhibition of γ-secretase by DAPT (a well-characterized γ-secretase inhibitor) in vitro. CONCLUSIONS: Dioscin, as a novel efficient γ-secretase activator, NICD1 nucleus translocation promoter and cell cycle regulator, markedly activated Notch1/Jagged1 pathway to promote hepato-proliferation. Our findings provide novel insights into dioscin as a natural product with facilitating liver regeneration after PH.

Huang Qi Decoction Prevents BDL-Induced Liver Fibrosis Through Inhibition of Notch Signaling Activation.

Notch signaling has been demonstrated to be involved in ductular reactions and fibrosis. Previous studies have shown that Huang Qi Decoction (HQD) can prevent the progression of cholestatic liver fibrosis (CLF). However, whether HQD affects the Notch signaling pathway is unclear. In this study, CLF was established by common bile duct ligation (BDL) in rats. At the end of the first week, the rats were randomly divided into a model group (i.e., BDL), an HQD group, and a sorafenib positive control group (SORA) and were treated for 3 weeks. Bile duct proliferation and liver fibrosis were determined by tissue staining. Activation of the Notch signaling pathway was evaluated by analyzing expressions of Notch-1, -2, -3, and -4, Jagged (JAG) 1, and Delta like (DLL)-1, -3, and -4. The results showed that HQD significantly reduced the deposition of collagen and the Hyp content of liver tissue and inhibited the activation of HSCs compared with the BDL group. In addition, HQD significantly decreased the protein and mRNA expressions of TGF-[Formula: see text]1 and [Formula: see text]-SMA. In contrast, HQD significantly enhanced expression of the Smad 7 protein. HQD also reduced biliary epithelial cell proliferation, and reduced the mRNA levels of CK7, CK8, CK18, SRY-related high mobility group-box gene (SOX) 9, epithelial cell adhesion molecule (EpCAM) and the positive areas of CK19 and OV6. In addition, the mRNA and protein expressions of Notch-3, -4, JAG1, and DLL-1, -3 were significantly reduced in the HQD compared to the BDL group. These results demonstrated that HQD may prevent biliary liver fibrosis through inhibition of the Notch signaling pathway, and it may be a potential treatment for cholestatic liver disease.

Brucine inhibits bone metastasis of breast cancer cells by suppressing Jagged1/Notch1 signaling pathways.

OBJECTIVE: To examine the effects of brucine on the invasion, migration and bone resorption of receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis. METHODS: The osteoclastogenesis model was builded by co-culturing human breast tumor MDA-MB-231 and mouse RAW264.7 macrophages cells. RANKL (50 ng/mL) and macrophage-colony stimulating factor (50 ng/mL) were added to this system, followed by treatment with brucine (0.02, 0.04 and 0.08 mmol/L), or 10 µmol/L zoledronic acid as positive control. The migration and bone resorption were measured by transwell assay and in vitro bone resorption assay. The protein expressions of Jagged1 and Notch1 were investigated by Western blot. The expressions of transforming growth factor-ß1 (TGF-ß1), nuclear factor-kappa B (NF-κB) and Hes1 were determined by enzyme-linked immunosorbent assay. RESULTS: Compared with the model group, brucine led to a dose-dependent decrease on migration of MDA-MB-231 cells, inhibited RANKL-induced osteoclastogenesis and bone resorption of RAW264.7 cells (P<0.01). Furthermore, brucine decreased the protein levels of Jagged1 and Notch1 in MDA-MB-231 cells and RAW264.7 cells co-cultured system as well as the expressions of TGF-ß1, NF-κB and Hes1 (P<0.05 or P<0.01). CONCLUSION: Brucine may inhibit osteoclastogenesis by suppressing Jagged1/Notch1 signaling pathways.

Matrine induces the hepatic differentiation of WB-F344 rat hepatic progenitor cells and inhibits Jagged 1/HES1 signaling.

Matrine is a Chinese medicine, which is widely utilized for the attenuation of liver injuries and promotion of liver regeneration. It was previously observed that the in vivo administration of matrine promoted oval cell­mediated liver regeneration in a rat model, suggesting that this compound may affect the differentiation of hepatic progenitor cells. The present study aimed to determine the mechanisms underlying this observation and to investigate the effect of matrine on the differentiation of the WB­F344 rat hepatic progenitor cell line. Matrine was administered to rats, and rat serum was collected. WB­F344 cells were cultured in the presence or absence of the rat serum for 24­72 h, and the effects on cell viability and proliferation were assessed using acridine orange/propidium iodide staining and a 3­(4,5­dimethylthiazol­2­yl) ­2,5­diphenyltetrazolium bromide assay. The expression of albumin (ALB, a hepatocyte marker) and the notch signaling pathway ligand, Jagged 1, were assessed using immunohistochemistry and western blotting, and the mRNA transcription of ALB, Jagged 1 and hairy and enhancer of split­1 (HES1, another notch signaling ligand) were measured using reverse transcription­polymerase chain reaction analysis. The results showed that proliferation of the WB­F344 cells was inhibited by matrine serum in a concentration­ and time­dependent manner. Matrine serum downregulated Jagged 1 and HES1, and upregulated ALB, indicating the induction of WB­F344 cell differentiation. The effects of matrine serum were reversed by supplementing the culture medium with 0.1 mol/l parathyroid hormone, a Notch signaling pathway activator. In conclusion, matrine induced hepatic differentiation of the hepatic progenitor cells, likely by inhibiting the Jagged 1/HES1 signaling pathway.

Melatonin prevents adverse myocardial infarction remodeling via Notch1/Mfn2 pathway.

Mitochondrial dysfunction is linked with myocardial infarction (MI), a disorder in which Notch1 has attracted increasing attention. However, the involvement of Notch1 in mitochondrial impairment after an MI is poorly understood, as is the role of mitochondrial fusion-associated protein 2 (Mfn2). Moreover, whether melatonin potentiates the Notch1/Mfn2 pathway in post-MI cardiac damage remains unclear. In our study, small interfering RNAs against Notch1 or Mfn2 and Jagged1 peptide were delivered via intramyocardial injection. At 3 days after these treatments, MI was induced by ligation of the anterior descending branch. We found that this ablation of Notch1 or Mfn2 aggravated post-MI injury, including worsened mitochondrial damage and increased generation of reactive oxygen species (ROS). In contrast, Jagged1 improved mitochondrial structure and function, decreased ROS production and attenuated post-MI injury. Interestingly, though Mfn2 expression was mildly regulated by Notch1 signaling in myocardium, Mfn2 deficiency nearly eliminated the cardioprotection by Jagged1, as evidenced by suppressed cardiac function, aggravated myocardial fibrosis, increased cell apoptosis, worsened mitochondrial impairment and enhanced oxidative stress. These observations revealed that Mfn2 plays an indispensable role in protection against MI-induced injury by Notch1. The mechanism might involve disrupting a damaging cycle of mitochondrial damage and ROS generation. Furthermore, melatonin activated Notch1 signaling and increased Mfn2 expression were reversed by luzindole, a nonselective antagonist of the melatonin receptor. Notably, melatonin attenuated post-MI injury in normal mice, but not in mice deficient in Notch1 or Mfn2. These results demonstrate that melatonin attenuates post-MI injury via the Notch1/Mfn2 pathway in a receptor-dependent manner.

Imperatorin exerts antiallergic effects in Th2-mediated allergic asthma via induction of IL-10-producing regulatory T cells by modulating the function of dendritic cells.

Imperatorin is a furanocoumarin compound which exists in many medicinal herbs and possesses various biological activities. Herein, we investigated the antiallergic effects of imperatorin in asthmatic mice and explored the immunomodulatory actions of imperatorin on immune cells. We used a murine model of ovalbumin (OVA)-induced asthma to evaluate the therapeutic potential of imperatorin. Additionally, bone marrow-derived dendritic cells (DCs; BMDCs) were used to clarify whether imperatorin exerts an antiallergic effect through altering the ability of DCs to regulate T cells. Oral administration of imperatorin to OVA-sensitized and -challenged mice decreased serum OVA-specific immunoglobulin E (IgE) production, attenuated the airway hyperresponsiveness (AHR), and alleviated airway inflammation in a dose-dependent manner. Notably, secretions of Th2 cytokines and chemokines were reduced, and numbers of interleukin (IL)-10-producing regulatory T cells (Tregs) increased in imperatorin-treated mice. Imperatorin inhibited proinflammatory cytokines and IL-12 production but enhanced IL-10 secretion by lipopolysaccharide (LPS)-stimulated BMDCs. Compared to fully mature DCs, imperatorin-treated DCs expressed high levels of the inducible costimulatory ligand (ICOSL) and Jagged1 molecules, and had the regulatory capacity to promote the generation of IL-10-producing CD4(+) T cells in vitro. Additionally, imperatorin directly suppressed activated CD4(+) T-cell proliferation and cytokine production. Imperatorin may possess therapeutic potential against Th2-mediated allergic asthma not only via stimulating DC induction of Tregs but also via direct inhibition of Th2 cell activation. These findings provide new insights into how imperatorin affects the Th2 immune response and the development of imperatorin as a Treg-type immunomodulatory agent to treat allergic asthma.

DHA Suppresses Primary Macrophage Inflammatory Responses via Notch 1/ Jagged 1 Signaling.

Persistent macrophages were observed in the lungs of murine offspring exposed to maternal LPS and neonatal hyperoxia. Maternal docosahexaenoic acid (DHA) supplementation prevented the accumulation of macrophages and improved lung development. We hypothesized that these macrophages are responsible for pathologies observed in this model and the effects of DHA supplementation. Primary macrophages were isolated from adult mice fed standard chow, control diets, or DHA supplemented diets. Macrophages were exposed to hyperoxia (O2) for 24 h and LPS for 6 h or 24 h. Our data demonstrate significant attenuation of Notch 1 and Jagged 1 protein levels in response to DHA supplementation in vivo but similar results were not evident in macrophages isolated from mice fed standard chow and supplemented with DHA in vitro. Co-culture of activated macrophages with MLE12 epithelial cells resulted in the release of high mobility group box 1 and leukotriene B4 from the epithelial cells and this release was attenuated by DHA supplementation. Collectively, our data indicate that long term supplementation with DHA as observed in vivo, resulted in deceased Notch 1/Jagged 1 protein expression however, DHA supplementation in vitro was sufficient to suppress release LTB4 and to protect epithelial cells in co-culture.

Astragalus injection attenuates bleomycin-induced pulmonary fibrosis via down-regulating Jagged1/Notch1 in lungs.

OBJECTIVES: Inhibition of Notch signalling is a potential therapeutic strategy for pulmonary fibrosis. This study was designed to investigate the antifibrosis effects and possible mechanism of astragalus injection (AI) on bleomycin (BLM)-induced pulmonary fibrosis in rats. METHODS: Pulmonary fibrosis was induced by intratracheal instillation of bleomycin (5 mg/kg) in male SD rats. All rats received daily intraperitoneally administration of dexamethasone (DEX, 3 mg/kg), astragalus injection (AI, 8 g/kg) or saline 1 day after bleomycin instillation daily for 28 days. Histological changes in the lung were evaluated by haematoxylin and eosin and Masson's trichrome staining. The expression of α-smooth muscle protein (α-SMA) was assayed by immunohistochemical (IHC). The mRNA and protein level of Jagged1, Notch1 and transforming growth factor-ß1 (TGF-ß1) was analysed by qPCR and Western blot. KEY FINDINGS: BLM-induced severe alveolitis and pulmonary fibrosis; together with significant elevation of α-SMA, TGF-ß1, Jagged1 and Notch1. Astragalus injection (AI, 8 g/kg) administration notably attenuated the degree of alveolitis and lung fibrosis, and markedly reduced the elevated levels of α-SMA, TGF-ß1, Jagged1 and Notch1 in lungs. CONCLUSIONS: Astragalus injection (AI, 8 g/kg) may exert protective effects on bleomycin-induced pulmonary fibrosis via downregulating Jagged1/Notch1 in lung.