Historical Evolution and Textual Research on Classic Prescription Danggui Buxuetang / 中国实验方剂学杂志

Danggui Buxuetang， derived from Clarifying Doubts about Damage from Internal and External Causes （Volume 2）： Treatise on Heat Injury to Stomach Qi（《内外伤辨惑论卷中·暑伤胃气论》） by LI Dongyuan in the Jin and Yuan dynasties， is a classic and famous formula for tonifying qi and generating blood that has been inherited and promoted by successive generations of medical practitioners and has been included in the "Catalogue of Ancient Classical Prescriptions （First Batch）" published by the National Administration of Traditional Chinese Medicine in 2018. The paper analyzed the historical origin， composition， dosage， processing， preparation， decocting， and taking methods， efficacy， and application of the classic formula Danggui Buxuetang by consulting ancient and modern literature and combining the key information examination principles of ancient classic prescriptions. A total of 604 pieces of information on relevant ancient literature were collected， including 186 ancient Chinese medical books， of which 40 （five in the Jin and Yuan dynasties， 19 in the Ming Dynasty， and 16 in the Qing Dynasty） had detailed records of composition， processing， and dosage. Danggui Buxuetang is mainly comprised of Astragali Radix and Angelicae Sinensis Radix. According to the ancient and modern dose conversion， there are 37.3-38.1 g of Astragali Radix and 7.5-7.6 g of Angelicae Sinensis Radix in the formula. Astragali Radix is preferably fried with honey and Angelicae Sinensis Radix with wine. Astragali Radix and Angelicae Sinensis Radix are decocted with 600 mL of water to 300 mL， and taken warm before meals. The main effect of this formula are described in ancient books as blood deficiency and fever， with symptoms of muscle fever， dryness and heat， irritability and thirst， red eyes and face， sleeplessness in daytime and night， and surging and feeble pulse which is weak under hard pressing， and it is a famous formula for replenishing qi and generating blood. Modern research shows that Danggui Buxuetang is commonly used in the treatment of various kinds of anemia， diabetic nephropathy， tumors， and cardiovascular and cerebrovascular diseases. The above research results can provide a reference for the subsequent development and research on the classic formula Danggui Buxuetang.

Investigation of Intestinal Absorption Characteristics of Multi-index Components of Danggui Buxuetang Based on Drug Absorption Simulating System / 中国实验方剂学杂志

ObjectiveTo investigate the intestinal absorption characteristics of multi-index components in Danggui Buxuetang with drug absorption simulating system （DASS） established by everted intestinal sac model. MethodThe intestinal absorption solution at different time points after administration of Danggui Buxuetang was collected and detected by high performance liquid chromatography （HPLC）， acetonitrile （A）-0.2% glacial acetic acid solution （B） was used as the mobile phase for gradient elution （0-16 min， 15%-23%A； 16-20 min， 23%-28%A； 20-25 min， 28%-30%A； 25-30 min， 30%A； 30-35 min， 30%-65%A； 35-45 min， 65%-95%A）， the detection wavelength was 302 nm. HPLC fingerprint of intestinal absorption solution was established and the common peak was calibrated， and the relative cumulative absorption rate of each index component was calculated. The relative cumulative absorption curves of components were fitted with various mathematical models by DDSolver 1.0 to explore the absorption law of different components. ResultThe absorption process of C2 （calycosin-7-glucoside） and C6 in Danggui Buxuetang was in line with zero-order equation， C9 was best fitted by Weibull equation， and the remaining 7 components were in line with Makoid-Banakar equation. C1 with C2， C3， C5， C7 and C10， C2 with C5 and C7， C3 with C4， C5， C7 and C10， C4 with C6 and C10， C5 with C7， C6 with C10， C7 with C10， C8 with C9 were absorbed simultaneously during the absorption process. With the prolongation of time， the overall cumulative absorption rate of Danggui Buxuetang increased. At 120 min， the overall cumulative absorption rate of Danggui Buxuetang exceeded 38%， and reached 49.14% at 180 min. ConclusionTen ingredients in Danggui Buxuetang are absorbed in the jejunum， but absorption law of various components is different， which shows that the intestinal absorption of compound preparations of traditional Chinese medicine （TCM） has multiple characteristics. Intestinal absorption study of TCM compound preparations with chemical composition as the index can reveal some of its absorption law， but it is not complete.

Effect of Danggui Buxuetang on Podocyte Pyroptosis in Diabetic Kidney Disease Rats： An Exploration Based on TXNIP/NLRP3/GSDMD Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo observe the effect of Danggui Buxuetang on podocyte pyroptosis in diabetic kidney disease （DKD） rats and to explore the possible mechanism of its prevention and treatment of DKD and podocyte pyroptosis. MethodEight of the 50 male SD rats were randomly classified into a normal group， and the remaining 42 were fed a high-glucose and high-fat diet for six weeks and then intraperitoneally injected with 35 mg·kg-1 streptozotocin （STZ） for inducing type 2 diabetes. After successful modeling， they were randomized into the model group， low- （0.72 g·kg-1） and high-dose （1.44 g·kg-1） Danggui Buxuetang group， and irbesartan （0.017 g·kg-1） group and gavaged with the corresponding drugs， while those in the normal group and model group with an equal volume of normal saline， once per day， for 20 weeks. During the medication， the fasting blood glucose （FBG） and 24 h urine protein （24 h-UTP） were measured regularly. After administration， the pathological changes in renal tissues were observed by periodic acid-silver metheramine （PASM） staining， followed by the observation of ultrastructural changes in podocytes under the transmission electron microscope （TEM）. Serum levels of interleukin-1β （IL-1β） and interleukin-18 （IL-18） were determined by enzyme-linked immunosorbent assay （ELISA）. The DNA damage in renal tissue cells of rats was detected by in situ nick end-labeling （TUNEL） assay. The protein expression levels of thioredoxin interacting protein （TXNIP）， cysteine-dependent aspartate-directed protease-1 （Caspase-1）， and gasdermin D （GSDMD） in renal tissues of rats were detected by immunohistochemistry （IHC）， the expression levels of nucleotide binding domain like receptor protein 3 （NLRP3） and Wilms tumor protein-1 （WT-1） in podocytes by immunofluorescent （IF） staining， and the expression levels of TXNIP/NLRP3/Caspase-1/GSDMD pathway proteins and Synaptopodin in renal podocytes by Western blot. ResultCompared with the normal group， the model group exhibited increased FBG and 24 h UTP， glomerular hypertrophy， mesangial hyperplasia， increased extracellular matrix， thickened basement membrane， K-W nodules， vacuolar degeneration in renal tubular epithelial cells， foot process fusion or loss， elevated serum IL-1β and IL-18 levels and TUNEL-positive cells in renal tissue， enhanced NLRP3 but diminished WT-1 expression in podocytes， down-regulated Synaptopodin protein expression， and up-regulated TXNIP/NLRP3/Caspase-1/GSDMD protein expression （P<0.01）. Compared with the model group， Danggui Buxuetang high-dose group remarkably lowered FBG， 24-h UTP， and TUNEL-positive cells in renal tissue， improved renal histopathology and podocyte injury and loss， down-regulated NLRP3 expression in podocytes and TXNIP/NLRP3/Caspase-1/GSDMD protein expression levels， and up-regulated WT-1 expression in podocytes and Synaptopodin protein expression （P<0.05， P<0.01）. ConclusionDanggui Buxuetang inhibits podocyte pyroptosis to reduce proteinuria and delays the development of DKD possibly by regulating the TXNIP/NLRP3/GSDMD signaling pathway.

Effect of Danggui Buxuetang on Podocyte Injury in Diabetic Kidney Disease Rats： An Exploration Based on RIPK1/RIPK3/MLKL Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo observe the effect of Danggui Buxuetang on the podocyte injury and receptor-interacting protein kinase 1/receptor-interacting protein kinase3/mixed lineage kinase domain-like protein （RIPK1/RIPK3/MLKL） signaling pathway in diabetic kidney disease （DKD） ratsand to explore its possible mechanism against DKD. MethodEight of the 50 SD rats were randomly classified intoa normal group， and the remaining were fed a high-glucose and high-fat diet for six weeks and then intraperitoneally injected with 0.035 g·kg-1streptozotocin （STZ） for inducing type 2 diabetes. After successful modeling，they were randomized into the model group，high- and low-dose （1.44，0.72 g·kg-1） Danggui Buxuetang groups， and irbesartan （0.017 g·kg-1）group. After 20 weeks of drug intervention， the fasting blood glucose （FBG）， kidney index （KI），and urinary microalbumin-to-urine creatinine ratio （UACR）were detected in each group. The pathological changes in renal tissue were observed by hematoxylin-eosin （HE） staining， followed by the observation of ultrastructural changes in podocytes under the transmission electron microscope. The levels of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in renal tissue of rats were determined by enzyme-linked immunosorbent assay （ELISA）， and the protein expression levels of RIPK1， RIPK3， and MLKL in rat kidney tissue by immunohistochemistry. The apoptosis rate of podocytes was detected by in situ nick end-labeling （TUNEL） assay. The mRNA expression levels of RIPK1， RIPK3， and MLKL in kidney tissue of rats were measured by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the protein expression levels of RIPK， RIPK3， and MLKL and podocyte marker Wilms tumor protein-1 （WT-1） in rat kidney tissue were assayed by Western blot. ResultCompared with the normal group， the model group exhibited elevated FBG， UACR， and KI （P<0.01）， glomerular hypertrophy， thickened basement membrane， increased extracellular matrix， mesangial hyperplasia， foot process fusion or loss， enhanced apoptosis in renal tissue， up-regulated TNF-α and IL-6 levels （P<0.01） and RIPK1/RIPK3/MLKL mRNA and protein expression （P<0.01）， and down-regulated WT-1 protein expression. Compared with the model group， Danggui Buxuetang high-dose group significantly reduced the levels of FBG， UACR， and KI， improved renal histopathology， podocyte loss， and apoptosis in renal tissue， down-regulated TNF-α and IL-6 levels and RIPK1/RIPK3/MLKL mRNA and protein expression （P<0.05， P<0.01）， and up-regulated WT-1 protein expression. ConclusionDanggui Buxuetang alleviates podocyte injury and delays the development of DKD possibly by regulating the RIPK1/RIPK3/MLKL signaling pathway.

Danggui Buxuetang Alleviates Oxidative Stress and Inflammation in Diabetic Kidney Disease Rats by Improving Mitochondrial Dysfunction of Podocytes / 中国实验方剂学杂志

ObjectiveTo investigate the intervention effect of Danggui Buxuetang on oxidative stress and inflammatory response in diabetic kidney disease （DKD） rats from its improvement of podocyte mitochondrial dysfunction. MethodSD rats were randomly divided into the control group and modeling group， and the ones in the latter group rats were fed a high-glucose and high-fat diet and then intraperitoneally injected with a small dose of streptozotocin （STZ） for inducing type 2 diabetes. The successfully modeled rats were randomized into the model group， high- and low-dose （1.44 and 0.72 g·kg-1） Danggui Buxuetang groups， and irbesartan （0.017 g·kg-1）group and gavaged with the corresponding drugs， while those in the normal and model groups with an equal volume of normal saline. After 20 weeks of drug intervention， the urinary microalbumin-to-urine creatinine ratio （UACR） and serum malondialdehyde （MDA） content and manganese superoxide dismutase （MnSOD） activity in each group were measured. The pathological changes in renal tissue were observed by Masson trichrome staining， and periodic acid-silver metheramine （PASM） staining， followed by the observation of ultrastructural changes in podocytes under the transmission electron microscope （TEM）. The expression level of reactive oxygen species （ROS） in rat kidney tissue was detected using a fluorescent probe dihydroethidium （DHE）. The protein expression levels of peroxisome proliferator-activated receptor γ -coactivator -1α （PGC-1α）， nucleotide-binding domain like receptor protein 3 （NLRP3）， and Wilms tumor protein-1 （WT-1） were measured by immunohistochemistry （IHC）， and the expression levels of NLRP3， interleukin-1β （IL-1β），and WT-1 in podocytes by immunofluorescence （IF） assay. The mRNA expression levels of PGC-1α and NLRP3 in the renal tissues were determined by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the protein expression levels of PGC-1α， MnSOD， NLRP3， and IL-1β were assayed by Western blot. ResultCompared with the normal group， the model group exhibited elevated UACR and MDA content， weakened MnSOD activity （P<0.01）， glomerular hypertrophy， thickened basement membrane， mesangial hyperplasia， increased extracellular matrix， K-W nodules， podocyte mitochondrial swelling， disordered mitochondrial cristae， foot process fusion or loss， vacuolization， increased ROS （P<0.01）， enhanced NLRP3 and IL-1β but diminished WT-1 expression in podocytes， down-regulated PGC-1α mRNA expression （P<0.01） and PGC-1α and MnSOD protein expression （P<0.01）， and up-regulated NLRP3 mRNA expression and NLRP3 and IL-1β protein expression （P<0.01）. Compared with the model group， Danggui Buxuetang high-dose group significantly decreased UACR and MDA， enhanced MnSOD activity （P<0.05， P<0.01）， improved renal histopathology and podocyte mitochondrial ultrastructure， decreased ROS （P<0.05， P<0.01） and NLRP3 and IL-1β expression in podocytes， enhanced WT-1 expression in podocytes， up-regulated the mRNA and protein levels of PGC-1α and MnSOD， and down-regulated the mRNA and protein levels of NLRP3 and IL-1β （P<0.05， P<0.01）. ConclusionDanggui Buxuetang alleviates oxidative stress， reduces inflammatory response， protects kidney， and delays the progression of DKD possibly by improving the mitochondrial dysfunction in podocytes of DKD rats.

Danggui Buxuetang in Malignant Tumor： A Review / 中国实验方剂学杂志

The occurrence and development of malignant tumors seriously affect the survival time and quality of life of people all over the world， and finding proper treatment methods has been a focus for doctors. Especially in recent years， traditional Chinese medicine （TCM） has developed and attracted the attention of doctors and patients. From the perspective of TCM syndrome differentiation and treatment， deficiency and stasis are the most fundamental causes of malignant tumors， and supplementing deficiency and removing stasis can be regarded as the basic criteria of TCM treatment of malignant tumors. TCM prescriptions can treat diseases by means of multiple components and multiple targets， with the characteristics of slight side effect and high efficacy， safety and cost performance， as well as easiness to be accepted and taken. As a classic recipe for invigorating Qi and generating blood， Danggui Buxuetang consists of Astragali Radix -Angelicae Sinensis Radix 5∶1. It has excellent effects in anti-tumor， bone marrow suppression after chemotherapy， immune function decline， anemia， heart and cerebral vessels protection， blood deficiency-led fever， diabetes， anti-atherosclerosis， anti-fatigue， anti-radiation， myocardial ischemia alleviation， inhibition of platelet aggregation， liver damage， etc. In addition， with many active anti-tumor ingredients， Danggui Buxuetang can exert anti-tumor effects via acting on multiple targets in different binding sites. However， there has been a lack of reviews on the role of Danggui Buxuetang in malignant tumors so far. Therefore， in this paper， the functions of Danggui Buxuetang in malignant tumors were reviewed. Besides， molecular docking technology was used to analyze the main active anti-tumor ingredients and action targets of Danggui Buxuetang.

Research Progress on Pharmacological Effect of Astragali Radix-Angelicae Sinensis Radix on Invigorating Qi and Activating Blood / 中国实验方剂学杂志

Astragali Radix-Angelicae Sinensis Radix （AA） is a basic pair of drugs mainly targeting the syndrome characteristics of Qi and blood diseases. LI Dong-yuan's Danggui Buxuetang （DBT） is composed of AA， which is mainly used to tonify Qi and generate blood， with main indications of Qi deficiency and blood deficiency， blood heat and so on. It is favored by doctors because of its refined prescription and remarkable curative effect. However， there are many compatibility ratios of AA in different prescriptions in ancient books， and their efficacy and indications are also slightly different. This research showed that DBT also had the effect of invigorating Qi and activating blood， and the previous study of the group showed that 3∶1 compatibility ratio of the two herbs in the total amount of 36 g had more obvious effect of invigorating Qi and activating blood. By consulting the relevant literature， it was found that the drug pair had a certain effect of invigorating Qi and activating blood in various compatibility ratios such as 1∶1， 3∶1， 1∶5， 3∶2， 2∶1， 5∶1. The corresponding pharmacological effect mainly included regulating the energy metabolism of substances， regulating immune function， reducing blood viscosity， anti-oxidation stress， anti-inflammation， lowering blood lipids， lowering blood sugar， protecting heart function， protecting blood vessel wall， intervening angiogenesis， fighting against organ tissue fibrosis and so on. Regardless of the AA single-medicine's activating blood effect and the theory that "Qi circulation leads to blood circulation" or the drug pair's manifestation in modern pharmacological effects， all of these have confirmed that AA's effect of invigorating Qi and activating blood does exist， and the difference of action performance caused by different ratios of AA is closely related to dosage and proportion， which needs further study. Based on the study focusing on the effect of tonifying Qi and generating blood， it is easy to ignore the effect of invigorating Qi and activating blood， which limits the clinical application of the latter. Therefore， the tonifying Qi and activating blood circulation effect of the drug pair is reviewed in this paper， so as to provide a theoretical basis for its clinical rational drug use and related research.

Effect of Danggui Buxuetang on Functional Activity of Endothelial Progenitor Cells Exposed to Shear Stress / 中国实验方剂学杂志

Objective:To investigate the effect of Danggui Buxuetang（DGBX）on the functional activity of rat endothelial progenitor cells（EPCs）exposed to different luminar shear stress （SS）. Method:EPCs isolated from rat bone marrow were incubated on a parallel plate flow chamber at a steady SS of 0， 0.12， 1.2， 2.4 Pa for 6 h，then the cells exposed to different SS were randomly divided into 8 groups： control group （perfused with serum free medium），simvastatin group（0.1 μmol·L^-1simvastatin），3 DGBX groups（low，medium，high-dose DGBX）and 3 inhibitor groups（3 DGBX groups with LY294002）. After 12 h，the samples were collected for the detection of cell proliferation ，migration，tubule formation ，the secretion of nitric oxide （NO） ，and the expressions of endothelial nitric oxide synthase（eNOS） mRNA and protein kinase B（Akt），respectively. Result:Compared with the control group，simvastatin and DGBX（high-dose）could both promote the functional activities and NO secretion，and up-regulate the expressions of eNOS mRNA and Akt protein in EPCs exposed to different SS（<italic>P</italic><0.05），while DGBX（mid-dose）could do these only at 0 Pa. However，LY294002 could inhibit all effects of DGBX on EPCs. Conclusion:SS seems to play an important role in the effect of DGBX on EPCs，and DGBX could promote the functional activity of EPCs exposed to SS by up-regulating the expressions of NO/eNOS/Akt.

Discussion on Particle Size of Powders and Decocted Powders in Famous Classical Formulas / 中国实验方剂学杂志

Objective:Powders and decocted powders account for about 1/3 in the Catalogue of Ancient Famous Classical Formulas （the First Batch）， and have a very important position. Determination of preparation technology and particle size in the pulverization process is the key step in the research and development of powders and decocted powders following the original methods. However， there are many terms describing the preparation technology and particle size of powders and decocted powders in ancient Chinese medical books， and the parameters are not clear. Due to the lack of unified basis of particle size， the existing research results have not formed a uniform consensus. Based on ancient textual researches and experimental results， this article discusses the particle size of decocted powders and powders. Method:Through textual researches of the preparation technology and particle size of powders and decocted powders and powder classification in the 2020 edition of Chinese Pharmacopoeia， the specifications of pulverized particle size were suggested. In addition， Xiebaisan and Danggui Buxuetang were taken as examples to investigate the influence of different particle sizes （4， 10， 24 mesh） on the preparation process of decocted powders and the obtained decoction. Result:The particle size of 4 mesh was equivalent to that of ancient as big as hemp bean. The contents of index components in Xiebaisan and Danggui Buxuetang with particle size of 4 mesh were higher than that of 10 mesh and 24 mesh， but the particle size of 50 mesh was too fine to be filtered. Conclusion:The suggested particle sizes of powders and decocted powders are recommended as Cumo is the power through 10-mesh sieve， Mo is the power through 24-mesh sieve， Ximo is the power through 80-mesh sieve， as big as hemp bean is the power through 4-mesh sieve and not through 10-mesh sieve.

Effect of Danggui Buxuetang on PKD1/NF-κB/MnSOD Signal Pathway in Bleomycin-induced Pulmonary Fibrosis in Rats / 中国实验方剂学杂志

Objective:To observe the effect of Danggui Buxuetang on lung histopathology and protein kinase D1 (PKD1), nuclear transcription factor-κB (NF-κB) and manganese superoxide dismutase (MnSOD)-mediated oxidative stress pathway in rats with pulmonary fibrosis induced by bleomycin, so as to explore the mechanism of intervention of pulmonary fibrosis.Method:Thirty-two male SPF SD rats were randomly divided into sham operation group, model group, Danggui Buxuetang group and prednisone group, with 8 rats in each group. Except the sham operation group, the other groups were prepared through the intratracheal instillation with bleomycin. After modeling for 24 h, the rats of Danggui Buxuetang group were administered with Danggui Buxuetang (0.81 g·kg-1). The rats of prednisone group were given aqueous solution of prednisone (0.005 g·kg-1). The rats of sham operation group and model group were given the same volume of saline. After 14 days of administration, blood was collected from the femoral artery, serum was separated, and the lungs were taken by thoracotomy. The pathological changes of rat lung tissues were observed by hematoxylin-eosin staining (HE) and Masson trichrome staining, and graded by Szapiel score and Ashcroft score at the same time. The content of serum malondialdehyde (MDA), and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) were determined. Real-time fluorescent quantitative polymerase chain reaction (Real-time PCR) and Western blot were used to measure mRNA and protein expressions of PKD1, NF-κB, MnSOD.Result:Compared with the rats in sham operation group, the rats in model group had higher Szapiel scores and Ashcroft scores (P<0.05), higher serum MDA content , but lower SOD, CAT and GSH-Px activities(P<0.01), moreover, the rat lung tissues in model group had higher mRNA and protein expressions of PKD1, NF-κB and MnSOD (P<0.01) than those in sham operation group. Compared with the rats in model group, the Szapiel scores and Ashcroft scores of the rats in Danggui Buxuetang group were decreased significantly（P<0.05）. The serum MDA content was decreased significantly, and SOD, CAT, GSH-Px activities were increased, whereas mRNA and protein expressions of PKD1, NF-κB, MnSOD in the rat lung tissues were decreased（P<0.05，P<0.01）.Conclusion:Danggui Buxuetang can reduce the degree of pulmonary fibrosis by regulating the anti-oxidation pathway of PKD1/NF-κB/MnSOD mitochondrial nucleus and improving the body's antioxidant capacity.

Protective Effect of Danggui Buxuetang on Endothelial Progenitor Cells Against Oxidative Stress Injury Induced by H2O2 / 中国实验方剂学杂志

Objective:To observe protective effect of Danggui Buxuetang (DBT) on oxidative stress injury of mouse bone marrow-derived endothelial progenitor cells (EPCs) against induced by hydrogen peroxide (H2O2). Method:Monocytes from bone marrow of mice were obtained by density gradient centrifugation, and EPCs were obtained by specific culture medium. The experiment was divided into blank group，model group，DBT group (100，200，400 mg·L-1). Methyl thiazolyl tetrazolium（MTT） assay was used to determine the survival rate of EPCs and establish the cell injury model induced by H2O2. MTT，transwell chamber，matrigel and superoxide fluorescent anion probe (DHE) were used to detect the proliferation，migration，in vitro angiogenesis and ROS level，detection of autophagy by Western blot. Result:Compared with blank group，the proliferation ability，migration ability，the number of lumens and the length of tubule branches of EPCs in the model group were significantly reduced (P<0.01)，the level of intracellular reactive oxygen species （ROS） was significantly increased (P<0.01)，the expression of p62，the light chain microtubule associated protein 1 protein light chain 3 Ⅱ type （LC3-Ⅱ） protein of microtubule associated protein 1，was significantly increased (P<0.01). Compared with model group，DBT group increased the ability of cell proliferation and migration （P<0.01）. In addition，DBT increased the expression of LC3-Ⅱ protein in a concentration dependent manner (P<0.01)，and decreased the expression of p62 protein (P<0.01). Conclusion:DBT can improve the autophagy level of EPCs under oxidative stress, promote the proliferation, migration and angiogenesis of injured EPCs, and protect the biological function of EPCs under oxidative stress.