Icariin alleviates high-fat diet-induced nonalcoholic fatty liver disease via up-regulating miR-206 to mediate NF-κB and MAPK pathways.

Nonalcoholic fatty liver disease (NAFLD) is an abnormal lipid accumulation disease in hepatocytes. The existing drugs for NAFLD have some side effects, so new therapeutic agents are required to be explored. In this study, the effect and mechanism of icariin (ICA) on high-fat diet-induced NAFLD were investigated. Firstly, a high-fat diet was used to construct a NAFLD rat model and HepG2 cells were treated with 1 mM free fatty acid (FFA). After ICA treatment, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured; liver injury and lipid deposition were observed by H&E and Oil Red O staining; interleukin-1ß (IL-1ß), IL-12, and IL-6 were measured by enzyme-linked immunosorbent assay. Additionally, qRT-PCR and western blot were performed to detect miR-206 expression and NF-κB/MAPK pathway-related protein expression in liver tissues and cells. After a variety of trials, we discovered that compared with the NAFLD group, ICA significantly reduced ALT, AST, TBil, TG, TC, and LDL-C levels and increased HDL-C levels, and improved liver tissue injury and lipid deposition. Moreover, ICA reduced IL-1ß, IL-12, and IL-6 levels in liver tissues and cells as well as inhibited MAPK and NF-κB-related protein expression in the liver tissues. Notably, ICA could significantly increase miR-206 expression in liver tissues and cells. Further experiments confirmed that inhibition of miR-206 was able to reverse the effect of ICA on NAFLD. In conclusion, ICA can alleviate NAFLD by upregulating miR-206 to mediate NF-κB and MAPK pathways.

Icariin Regulates EMT and Stem Cell-Like Character in Breast Cancer through Modulating lncRNA NEAT1/TGFß/SMAD2 Signaling Pathway.

Metastases and drug resistance are the major risk factors associated with breast cancer (BC), which is the most common type of tumor affecting females. Icariin (ICA) is a traditional Chinese medicine compound that possesses significant anticancer properties. Long non-coding RNAs (lncRNAs) are involved in a wide variety of biological and pathological processes and have been shown to modulate the effectiveness of certain drugs in cancer. The purpose of this study was to examine the potential effect of ICA on epithelial mesenchymal transition (EMT) and stemness articulation in BC cells, as well as the possible relationship between its inhibitory action on EMT and stemness with the NEAT1/transforming growth factor ß (TGFß)/SMAD2 pathway. The effect of ICA on the proliferation (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony assays), EMT (Western blotting, immunofluorescence, and wound healing), and stemness (mammosphere formation assays, Western blotting) of BC cells were examined. According to the findings, ICA suppressed the proliferation, EMT, and stem cell-like in MDA-MB-231 cells, and exerted its inhibitory impact by downregulating the TGFß/SMAD2 signaling pathway. ICA could significantly downregulate the expression of lncRNA NEAT1, and silencing NEAT1 enhanced the effect of ICA in suppressing EMT and expression of different stem cell markers. In addition, silencing NEAT1 was found to attenuate the TGFß/SMAD2 signaling pathway, thereby improving the inhibitory impact of ICA on stemness and EMT in BC cells. In conclusion, ICA can potentially inhibit the metastasis of BC via affecting the NEAT1/TGFß/SMAD2 pathway, which provides a theoretical foundation for understanding the mechanisms involved in potential application of ICA for BC therapy.

Anti-Alzheimers molecular mechanism of icariin: insights from gut microbiota, metabolomics, and network pharmacology.

BACKGROUND: Icariin (ICA), an active ingredient extracted from Epimedium species, has shown promising results in the treatment of Alzheimer's disease (AD), although its potential therapeutic mechanism remains largely unknown. This study aimed to investigate the therapeutic effects and the underlying mechanisms of ICA on AD by an integrated analysis of gut microbiota, metabolomics, and network pharmacology (NP). METHODS: The cognitive impairment of mice was measured using the Morris Water Maze test and the pathological changes were assessed using hematoxylin and eosin staining. 16S rRNA sequencing and multi-metabolomics were performed to analyze the alterations in the gut microbiota and fecal/serum metabolism. Meanwhile, NP was used to determine the putative molecular regulation mechanism of ICA in AD treatment. RESULTS: Our results revealed that ICA intervention significantly improved cognitive dysfunction in APP/PS1 mice and typical AD pathologies in the hippocampus of the APP/PS1 mice. Moreover, the gut microbiota analysis showed that ICA administration reversed AD-induced gut microbiota dysbiosis in APP/PS1 mice by elevating the abundance of Akkermansia and reducing the abundance of Alistipe. Furthermore, the metabolomic analysis revealed that ICA reversed the AD-induced metabolic disorder via regulating the glycerophospholipid and sphingolipid metabolism, and correlation analysis revealed that glycerophospholipid and sphingolipid were closely related to Alistipe and Akkermansia. Moreover, NP indicated that ICA might regulate the sphingolipid signaling pathway via the PRKCA/TNF/TP53/AKT1/RELA/NFKB1 axis for the treatment of AD. CONCLUSION: These findings indicated that ICA may serve as a promising therapeutic approach for AD and that the ICA-mediated protective effects were associated with the amelioration of microbiota disturbance and metabolic disorder.

Icariin inhibits isoproterenol-induced cardiomyocyte hypertropic injury through activating autophagy via the AMPK/mTOR signaling pathway.

Icariin (ICA), a bioactive flavonoid compound derived from Epimedium, have been demonstrated possessing anti-oxidative stress, anti-inflammation in the cardiovascular disease. But its effects on cardiomyocyte hypertrophy and the underlying mechanisms remains unclear. Here we found that ICA alleviated ISO-induced H9c2 or NRCM myocytes hypertrophy, assessed by surface area and the expression of ANP, BNP and ß-MHC. Furthemore, ICA reversed cardiomcytes enlargment by suppresing apoptotic injury and increasing autophagic flux. By contrast, 3-MA, an autophagy inhibitor, could abolished the antihypertrophic and pro-autophagic flux effects of ICA. Mechanistically, ICA increased the phosphorylation levels of AMPK and autophagy-related markers beclin-1, Atg5 and the LC3II/I ratio, and decreased phosphorylated mTOR. But the effects of ICA on ISO-induced cardiomyocytes hypertrophy were attenuated by selective AMPK inhibitor Compound C. In conclusion, these findings indicated that ICA attenuated cardiomyocyte hypertrophy induced by ISO and prevented cell injury, and the specific mechanism was mediated by AMPK/mTOR pathway to enhance autophagy and reduce autophagy-related cardiomyocyte apoptosis.

Icariin Promotes the Osteogenic Action of BMP2 by Activating the cAMP Signaling Pathway.

Icariin (ICA) is the main active flavonoid glucoside from herbs of the genus Epimedium; in traditional Chinese medicine, these herbs have long been prescribed for the treatment of bone fractures and osteoporosis. Several studies have shown that treatment with ICA can increase osteogenic differentiation and reduce bone loss in vivo and in vitro. However, the definite signaling pathway of this osteogenic effect remains unclear. In this study, we selected bone morphogenetic protein 2 (BMP2)-induced osteoblastic differentiation of multipotent mesenchymal progenitor C2C12 cells as a model of osteoblast differentiation. We investigated the effects of ICA on C2C12 cells osteogenic differentiation and the underlying molecular mechanisms. We found that ICA could enhance BMP2-mediated osteoblastic differentiation of C2C12 cells in a dose-dependent manner. Treatment with ICA activated the cAMP/PKA/CREB signaling axis in a time-dependent manner. Blocking cAMP signaling using the PKA selective inhibitor H89 significantly inhibited the stimulatory effect of ICA on osteogenesis. Therefore, the osteoinductive potential and the low cost of ICA indicate that it is a promising alternative treatment or promoter for enhancing the therapeutic effects of BMP2.

Icariin Protects against Glucocorticoid-Induced Osteonecrosis of the Femoral Head in Rats.

BACKGROUND/AIMS: Glucocorticoid (GC)-related osteonecrosis of the femoral head (ONFH) is a common complication following administration of steroids to treat many diseases. Our previous study demonstrated that icariin (ICA) might have a beneficial effect on the bone marrow mesenchymal stem cells (BMSCs) of patients with steroid-associated osteonecrosis. In this study, we investigated the underlying mechanisms of ICA associated with the potential enhancement of osteogenesis and anti-adipogenesis in GC-related ONFH. METHODS: In vitro cell proliferation was evaluated by CCK-8 assay. Alizarin red S and alkaline phosphatase (ALP) activity were used to measure osteogenic differentiation, while adipogenic differentiation was revealed by oil red O staining and TG content assay. The expression level of osteogenesis-associated genes and PPARγ was evaluated by RT-qPCR, western blotting and immunofluorescence. A total of 30 female SD rats were randomly separated into three groups: a control group, a methylprednisolone (MPS) group and a MPS + ICA group. Serum ALP and TG (triglyceride), micro-CT scanning, histological and immunohistochemical analyses were performed in the animal model. RESULTS: In the in vitro study, ICA promoted proliferation, improved osteogenic differentiation and suppressed adipogenic differentiation of BMSCs treated with MPS. The group treated with MPS and 10-6 M ICA expressed higher levels of Runx2, ALP, bone morphogenetic protein (BMP) 2, and OC and lower expression of PPARγ than the MPS group. In the in vivo study, ICA prevented bone loss in a rat model of GC-related ONFH as shown by micro-CT scanning, histological and immunohistochemical analyses. CONCLUSIONS: ICA is an effective compound for promoting bone repair and preventing or delaying the progression of GC-associated ONFH in rats. This effect can be explained by its ability to improve the balance between adipogenesis and osteogenesis, indicating that ICA is an effective candidate for management of GC-associated ONFH.

High-strength double-network silk fibroin based hydrogel loaded with Icariin and BMSCs to inhibit osteoclasts and promote osteogenic differentiation to enhance bone repair.

Large bone defects cause significant clinical challenges due to the lack of optimal grafts for effective regeneration. The tissue engineering way that requires the combination of biomaterials scaffold, stem cells and proper bioactive factors is a prospective method for large bone repair. Here, we synthesized a three-arm host-guest supramolecule (HGSM) to covalently crosslinking with the naturally derived polymer methacrylated silk fibroin (SFMA). The combination of HGSM and SFMA can form a high strength double-crosslinked hydrogel HGSFMA, that serve as the hydrogel scaffold for bone marrow mesenchymal stem cells (BMSCs) growing. Icariin (ICA) loaded in the HGSFMA hydrogel can promote the osteogenesis efficiency of BMSCs and inhibit the osteoclasts differentiation. Our findings demonstrated that the HGSFMA/ICA hydrogel effectively promoted the in vitro adhesion, proliferation, and osteogenic differentiation of BMSCs. Rat femoral defects model show that this hydrogel can completely repair femoral damage within 4 weeks and significantly promote the secretion of osteogenesis-related proteins. In summary, we have prepared an effective biomimetic bone carrier, offering a novel strategy for bone regeneration and the treatment of large-scale bone defects.

Icariin activates far upstream element binding protein 1 to regulate hypoxia-inducible factor-1α and hypoxia-inducible factor-2α signaling and benefits chondrocytes.

Icariin (ICA) is a typical flavonoid glycoside derived from epimedium plants. It has both anabolic and anti-catabolic effects to improve bone mineral density and reduce bone microstructural degradation. However, the effect and underlying mechanism of ICA on the proliferation and metabolism of chondrocyte and synthesis of extracellular matrix are still unclear. This study aimed to investigate the role and regulation of far upstream element binding protein 1 (FUBP1) in chondrocytes treated with ICA to maintain homeostasis and suppress inflammatory responses. In the study, the effect of ICA on chondrocytes with overexpressed or silenced FUBP1 was detected by the MTS and single-cell cloning methods. The expression of hypoxia-inducible factor-1/2α (HIF-1/2α), FUBP1, matrix metalloproteinase (MMP)9, SRY-box transcription factor 9 (SOX9), and type II collagen (Col2α) in ATDC5 cells, a mouse chondrogenic cell line, treated with ICA was evaluated by immunoblotting. Western blotting revealed 1 µM ICA to have the most significant effect on chondrocytes. Alcian blue staining and colony formation assays showed that the promoting effect of ICA was insignificant in FUBP1-knockdown cells (P > 0.05) but significantly enhanced in FUBP1-overexpressed cells (P < 0.05). Western blot results from FUBP1-knockdown cells treated with or without ICA showed no significant difference in the expression of FUBP1, HIF-1/2α, MMP9, SOX9, and Col2α proteins, whereas the same proteins showed increased expression in FUBP1-overexpressed chondrocytes; moreover, HIF-2α and MMP9 expression was significantly inhibited in FUBP1-knockdown chondrocytes (P < 0.05). In conclusion, as a bioactive monomer of traditional Chinese medicine, ICA is beneficial to chondrocytes.

Phase-contrast imaging with synchrotron hard X-ray reveals the effect of icariin on bone tissue morphology and microstructure in rabbits with early glucocorticoid-induced osteonecrosis of the femoral head.

Background: Phase-contrast imaging (PCI) with synchrotron hard X-ray was used to observe the changes in bone tissue morphology and microstructure in rabbit models of early glucocorticoid-induced osteonecrosis of the femoral head (ONFH), and to evaluate the intervention effect of Icariin. Methods: Fifty mature New Zealand rabbits (weighing 2.5-3.0 kg) were randomly divided into a control group (n = 10), a glucocorticoid group (n = 20), and an Icariin group (n = 20). The glucocorticoid group and the Icariin group were sequentially injected with lipopolysaccharide (LPS) and methylprednisolone (MPS) to establish a glucocorticoid-induced ONFH animal model. The Icariin group was given Icariin solution when methylprednisolone was injected for the first time, and the control group and glucocorticoid group were given the same amount of normal saline. Animals were sacrificed after 6 weeks, and bilateral femoral head specimens were taken for research. The right femoral head was observed by PCI with synchrotron hard X-ray technology, and the left femoral head was verified by Micro-CT scanning and HE staining. Results: Forty-three animals (nine in the control group, sixteen in the glucocorticoid group, and eighteen in the Icariin group) were included in the study. PCI with synchrotron hard X-ray revealed that the trabecular bone in the glucocorticoid group was thinned, broken, and structurally damaged, whereas the trabecular bone in the Icariin group had normal volume, thickness, and a relatively intact structure. Micro-CT scan reconstruction and HE staining were used to verify the reliability of this technique in identifying osteonecrosis. Conclusion: The effects of Icariin were observed in an early glucocorticoid-induced ONFH rabbit model using PCI with synchrotron hard X-ray. Icariin weakens the destructive effect of glucocorticoids on bone tissue structure, improves bone tissue morphology, and stabilizes bone microstructure. This technique may provide a definitive, non-invasive alternative to histological examination for the diagnosis of early ONFH.

Icariin promotes the repair of bone marrow mesenchymal stem cells in rabbit knee cartilage defects via the BMP/Smad pathway.

Background: Icariin (ICA) has been widely used in the treatment of osteoporosis. However, the potential mechanism of its critical role in repairing knee cartilage damage still needs to be further clarified. Methods: First, rabbit bone marrow mesenchymal stem cells (BMSCs) were isolated, cultured, and identified. Subsequently, BMSCs were treated with different concentrations of ICA. Cell Counting Kit 8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) were used to evaluate the cell proliferation in each group. Alcian Blue staining, immunofluorescence, and western blotting were used to evaluate the ability of BMSCs to differentiate cartilage. In addition, a rabbit knee cartilage injury model was established. Evaluation of cartilage defects in each group was performed according to the classification system outlined by the International Cartilage Repair Society (ICRS). Hematoxylin and eosin (HE), Alcian Blue, and immunohistochemistry were used to analyze the pathological status of knee cartilage. Results: In vitro, the results showed that ICA promoted the cartilage differentiation of BMSCs as well as cell proliferation. In addition, ICA promoted the expression of type II collagen (COL2A1), aggrecan, and bone morphogenetic protein 2 (BMP2) in BMSCs, while BMP-Smad inhibitor (Noggin) reversed the repair effect of ICA on BMSCs. In vivo, our results showed that the ICRS score of the BMSC and ICA treatment group was higher. Moreover, BMSC and ICA treatment promoted the proliferation of chondrocytes and repaired the cartilage-like tissue on the surface of cartilage defect. Conclusions: The combined application of ICA and BMSCs can repair rabbit knee cartilage injury by regulating the BMP/Smads pathway, indicating that ICA and BMSCs may be a viable clinical treatment strategy for knee cartilage damage.

Synergistically Promoting Bone Regeneration by Icariin-Incorporated Porous Microcarriers and Decellularized Extracellular Matrix Derived From Bone Marrow Mesenchymal Stem Cells.

Multifunctionality has becoming essential for bone tissue engineering materials, such as drug release. In this study, icariin (ICA)-incorporated poly(glycolide-co-caprolactone) (PGCL) porous microcarriers were fabricated and then coated with decellularized extracellular matrix (dECM) which was derived from bone marrow mesenchymal stem cells (BMSC). The porous structure was generated due to the soluble gelatin within the microcarriers. The initial released ICA in microcarriers regulated osteogenic ECM production by BMSCs during ECM formation. The dECM could further synergistically enhance the migration and osteogenic differentiation of BMSCs together with ICA as indicated by the transwell migration assay, ALP and ARS staining, as well as gene and protein expression. Furthermore, in vivo results also showed that dECM and ICA exhibited excellent synergistic effects in repairing rat calvarial defects. These findings suggest that the porous microcarriers loaded with ICA and dECM coatings have great potential in the field of bone tissue engineering.

Therapeutic effects and mechanism of ferulic acid and icariin in mammary gland hyperplasia model rats via regulation of the ERK pathway.

BACKGROUND: Ferulic acid (FA) and icariin (ICA), as the active compounds derived from Angelica sinensis and Epimedium brevicornum Maxim, respectively, have been shown to promote blood circulation, regulate menstruation, exhibit anti-inflammatory effects, and modulate estrogen levels. The aim of this study was to elucidate the possible mechanism of FA, ICA, and FA-ICA on estrogen-induced mammary gland hyperplasia (MGH) in rats. METHODS: Hematoxylin and eosin (HE) staining was performed to record the pathological changes in breast tissue, and enzyme-linked immunosorbent assay (ELISA) was utilized to determine the serum levels of luteinizing hormone (LH), PRL (prolactin), testosterone (T), estradiol (E2), follicular stimulating hormone (FSH), and progesterone (P). The message RNA (mRNA) expression levels of extracellular signal-regulated kinase 1 (ERK1), extracellular signal-regulated kinase 2 (ERK2), estrogen receptor (ER), and progesterone receptor (PR) were detected by real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. Furthermore, ER, phosphorylated-ER, PR, p-PR, ERK1/2, and p-ERK1/2 protein factors in the ERK signaling pathway were evaluated by Western blotting. Simultaneously, changes in breast height, diameter, body weight, and organ index were all recorded. RESULTS: We found that FA and ICA could modulate the degree of breast swelling, and reduce the body weight, thymus index, and uterus index. Furthermore, it could also block the pathological changes of MGH, including the number of mammary lobules, and the proliferation or expansion of acini and ducts. Moreover, treatment with FA and ICA remarkably down-regulated the serum expression levels of LH, PRL, T, and E2, as well as the mRNA expression levels of ERα, PR, ERK1, and ERK2. Additionally, protein levels of ERα, p-ERα, PR, p-PR, ERK1/2, and p-ERK1/2 in breast tissue were down-regulated, however the serum content of FSH and P was up-regulated. CONCLUSIONS: Our outcomes revealed that FA and ICA might potentially inhibit ERα, PR, ERK1/2, and their phosphorylated proteins via the ERK signaling pathway, thus indicating a positive feedback control for the degree of breast hyperplasia.

Preparation of ICA-loaded mPEG-ICA nanoparticles and their application in the treatment of LPS-induced H9c2 cell damage.

Hydrophilic polyethylene glycol monomethyl ether (mPEG) was grafted onto Icariin (ICA) by succinic anhydride to form a polyethylene glycol-Icariin (mPEG-ICA) polymer. The structure of the polymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). mPEG-ICA nanoparticles loaded with ICA were prepared by physical embedding of ICA by dialysis. The particle size was determined to be (220 ± 13.7) nm, and the ζ potential was (2.30 ± 1.33) mV by dynamic light scattering (DLS). Under a transmission electron microscope (TEM), the nanoparticles were spherical, and the morphology was regular. In the medium with pH 7.4, the drug release rate of mPEG-ICA nanoparticles reached (52.80 ± 1.70)% within 72 h. At pH 6.8, the cumulative drug release of nanoparticles reached (75.66 ± 0.17)% within 48 h. Treatment of the nanoparticles with LPS-treated H9c2 cells maintained cell viability, reduced LDH release and exerted antiapoptotic effects. Moreover, ICA-loaded mPEG-ICA nanoparticles significantly decreased the mRNA expression of the myocardial inflammatory cytokines TNF-α, IL-1ß and IL-6M. In conclusion, ICA-loaded mPEG-ICA nanoparticles protected against LPS-induced H9c2 cell injury.

Icariin inhibits the inflammation through down-regulating NF-κB/HIF-2α signal pathways in chondrocytes.

Articular cartilage injury or defect is a common disease and is mainly characterized by cartilage degradation because of chondrocyte inflammation. By now, there are no effective drugs and methods to protect articular cartilage from degradation. Icariin (ICA) is a typical flavonoid compound extracted from Epimedii Folium with anti-inflammatory and bone-protective effects. Our previous studies demonstrate that ICA up-regulates HIF-1α expression and glycolysis in chondrocytes and maintains chondrocyte phenotype. As another member of HIFs family, HIF-2α always plays a key role in inflammation. The effect of ICA on HIF-2α is unclear by now. In the present study, we confirmed the findings in our previous study that ICA promoted not only chondrocyte vitality and extracellular matrix (ECM) synthesis, but also the anti-inflammatory effect of ICA. In bone defect mice, ICA inhibited the expressions of NF-κB and HIF-2α. In TNF-α-treated ADTC5 chondrocytes, ICA neutralized the activation of IKK (IKK phosphorylation), the phosphorylation of IkB and NF-κB and the expression of HIF-2α. Furthermore, ICA inhibited the nucleus transfer of NF-κB and the expressions of MMP9 and ADAMTS5, two key targets of NF-κB/HIF-2α signal pathway. Taken together, the present study demonstrated that ICA may increase the vitality of chondrocytes by suppressing the inflammatory injury through the inhibition on NF-κB/HIF-2α signaling pathway. ICA is one effective candidate drug for the treatment of articular cartilage injury.

Electrospun Icariin-Loaded Core-Shell Collagen, Polycaprolactone, Hydroxyapatite Composite Scaffolds for the Repair of Rabbit Tibia Bone Defects.

BACKGROUND: Electrospinning is a widely used technology that can produce scaffolds with high porosity and surface area for bone regeneration. However, the small pore sizes in electrospun scaffolds constrain cell growth and tissue-ingrowth. In this study, novel drug-loading core-shell scaffolds were fabricated via electrospinning and freeze drying to facilitate the repair of tibia bone defects in rabbit models. MATERIALS AND METHODS: The collagen core scaffolds were freeze-dried containing icariin (ICA)-loaded chitosan microspheres. The shell scaffolds were electrospun using collagen, polycaprolactone and hydroxyapatite materials to form CPH composite scaffolds with the ones containing ICA microspheres named CPHI. The core-shell scaffolds were then cross-linked by genipin. The morphology, microstructure, physical and mechanical properties of the scaffolds were assessed. Rat marrow mesenchymal stem cells from the wistar rat were cultured with the scaffolds. The cell adhesion and proliferation were analysed. Adult rabbit models with tibial plateau defects were used to evaluate the performance of these scaffolds in repairing the bone defects over 4 to 12 weeks. RESULTS: The results reveal that the novel drug-loading core-shell scaffolds were successfully fabricated, which showed good physical and chemical properties and appropriate mechanical properties. Furthermore, excellent cells attachment was observed on the CPHI scaffolds. The results from radiography, micro-computed tomography, histological and immunohistochemical analysis demonstrated that abundant new bones were formed on the CPHI scaffolds. CONCLUSION: These new core-shell composite scaffolds have great potential for bone tissue engineering applications and may lead to effective bone regeneration and repair.

Icariin increases chondrocyte vitality by promoting hypoxia-inducible factor-1α expression and anaerobic glycolysis.

BACKGROUND: Articular cartilage is a unique avascular tissue in which chondrocytes are embedded in extracellular matrix (ECM). The decreased ECM resulting from the loss of articular chondrocyte viability leads to degenerative diseases such as osteoarthritis (OA). This study aims to investigate the effect of icariin (ICA) on ECM synthesis and chondrocyte viability. METHODS: Micromass culture, alcian blue, and Safran O (SO)/fast green staining were used to investigate chondrocyte viability and ECM synthesis in chondrocytes treated with ICA. The expression of hypoxia-inducible factor-1α (HIF-1α), SOX9, and anaerobic glycolysis enzymes were detected by western blot and reverse transcription-quantitative polymerase chain reaction. RESULTS: ICA, an active flavonoid component of Herba epimedii, was demonstrated to increase chondrocyte viability and ECM synthesis. HIF-1α is a key mediator of chondrocyte response to fluctuations in oxygen availability during cartilage development or damage, and its expression was unregulated by ICA treatment. Meanwhile, ICA treatment increased SOX9 expression, which is a key regulator of ECM synthesis. Furthermore, ICA treatment increased the expression of glucose transporter 1 (GLUT1), glucose-6-phosphate dehydrogenase (G6PD), phosphoglycerate kinase 1 (PGK1), and pyruvate dehydrogenase kinase 1 (PDK1), which contribute to glucose transfer and anaerobic glycolysis. CONCLUSIONS: The present study revealed that ICA treatment facilitates chondrocyte vitality by promoting HIF-1α expression and anaerobic glycolysis. Therefore, ICA could be a novel clinical treatment for OA.

mPEG-icariin nanoparticles for treating myocardial ischaemia.

Icariin (ICA), a major active ingredient from Chinese medicine, has unique pharmacological effects on ischaemic heart disease. However, its hydrophobic property limits its administration and leads to poor efficacy. This work aimed to change its hydrophobic property and improve the treatment efficacy. We designed a new nano-drug to increase the ICA delivery. ICA was modified with hydrophilic polyethylene glycol monomethyl ether (mPEG) by a succinic anhydride linker to form a polyethylene glycol-icariin (mPEG-ICA) polymer. The structure of this polymer was identified by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The content of ICA in the polymer was 32% as detected by ultraviolet spectrophotometry. mPEG-ICA nanoparticles, of 143.3 nm, were prepared by the dialysis method, and zeta potential was 0.439 mV by dynamic light scattering. The nanoparticles had a spherical shape on transmission electron microscopy. In media with pH 7.4 and 6.8, ICA release from mPEG-ICA nanoparticles after 72 h was about 0.78% and 64.05%, respectively, so the ICA release depended on the release media pH. On MTT and lactate dehydrogenase activity assay, mPEG-ICA nanoparticles could reduce cell damage induced by oxgen-glucose deprivation. Hoechst 33258 staining and TUNEL and AnnexinV-FITC/PI double staining showed that ICA nanoparticles could increase the activity of H9c2 cardiomyocytes under oxgen-glucose deprivation conditions by decreasing apoptosis. ICA modified by hydrophilic mPEG could improve its efficacy.