OBJECTIVES: To investigate the effects of Naoluo Xintong Decoction (NLXTD) on proliferation of rat brain microvascular endothelial cells (BMECs) after oxygen-glucose deprivation/reoxygenation (OGD/R) injury and role of the HIF-1α/VEGF pathway in mediating its effect. METHODS: Using a BMEC model of OGD/R, we tested the effects of 10% NLXTD-medicated rat serum, alone or in combination with 2ME2 or 10% NAKL, on cell proliferation, migration, tube-forming ability and permeability using CCK-8 assay, Transwell chamber assay, tube formation assay and permeability assay. Cellular expressions of VEGF and Notch were detected using ELISA and laser confocal immunofluorescence analysis, and the expressions of HIF-1α, VEGFR2, Notch1, ERK and P-ERK1/2 proteins were detected with Western blotting. RESULTS: OGD/R injury significantly decreased viability of BMECs. NLXTD treatment of the cells with OGD/R could significantly promoted cell proliferation, migration and tube formation ability, but these effects were strongly attenuated by application of 2ME2. NLXTD treatment also significantly increased the percentages of VEGF- and Notch-positive cells in the cell models and obviously enhanced the expression levels of HIF-1α, VEGFR2, Notch1 and P-ERK1/2. CONCLUSIONS NLXTD promotes proliferation, migration, and tube formation of rat BMECs after OGD/R injury possibly by activating the HIF-1α/VEGF signaling pathway.
Animals ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Drugs, Chinese Herbal/pharmacology* ; Vascular Endothelial Growth Factor A/metabolism* ; Endothelial Cells/metabolism* ; Rats ; Cell Proliferation/drug effects* ; Signal Transduction/drug effects* ; Glucose ; Brain/blood supply* ; Cells, Cultured ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor Receptor-2/metabolism* ; Oxygen/metabolism* ; Cell Hypoxia

This study aims to investigate the effect and mechanism of the herb pair Agrimoniae Herba-Coptidis Rhizoma in inhibiting angiogenesis in the colorectal cancer inflammatory microenvironment by using the method of network pharmacology and the zebrafish model. The method of network pharmacology was employed to obtain the active components, potential core targets, and signaling pathways regulated by the herb pair in inhibiting angiogenesis in the inflammatory microenvironment of colorectal cancer, on the basis of which the underlying mechanism was predicted. The zebrafish model of colorectal cancer was established, and the inflammatory microenvironment was modeled. The effects of different concentrations of the herb pair on the area, number, and length of intersegmental vessels(ISVs) of the zebrafish model were observed. Western blot and real-time quantitative PCR were employed to measure the protein and mRNA levels, respectively, of vascular endothelial growth factor A(VEGFA), vascular epidermal growth factor receptor 2(VEGFR2, also known as kdrl, Flk1), and vascular epidermal growth factor receptor 3(VEGFR3, also known as Flt4). A total of 18 active components and 488 potential targets of Agrimoniae Herba-Coptidis Rhizoma were predicted, and 108 common targets were shared by the herb pair and the disease. According to the results of KEGG pathway enrichment analysis, the angiogenesis-related factors VEGFA, kdrl, and Flt4 in the VEGFA/VEGFR2 signaling pathway were selected for verification. The zebrafish experiment showed that compared with the blank group, the model group showed increased area, number, and length of ISVs in the inflammatory microenvironment. Compared with the model group, the herb pair decreased the area, number, and length of ISVs in a concentration-dependent manner. Compared with the blank group, the model group showed up-regulated protein and mRNA levels of VEGFA, kdrl, and Flt4 in the inflammatory microenvironment. Compared with the model group, the herb pair down-regulated the protein and mRNA levels of VEGFA, kdrl, and Flt4 in a concentration-dependent manner. The results indicated that in the colorectal cancer inflammatory microenvironment, the herb pair Agrimoniae Herba-Coptidis Rhizoma could inhibit angiogenesis via multiple components, targets, and pathways. The anti-angiogenesis effect might be related to the down-regulation of the expression levels of angiogenesis-related factors VEGFA, kdrl, and Flt4 in the VEGFA/VEGFR2 signaling pathway.
Zebrafish ; Animals ; Drugs, Chinese Herbal/pharmacology* ; Network Pharmacology ; Colorectal Neoplasms/metabolism* ; Neovascularization, Pathologic/drug therapy* ; Humans ; Vascular Endothelial Growth Factor A/metabolism* ; Tumor Microenvironment/drug effects* ; Angiogenesis Inhibitors/pharmacology* ; Vascular Endothelial Growth Factor Receptor-2/metabolism* ; Signal Transduction/drug effects* ; Coptis chinensis ; Inflammation/drug therapy* ; Angiogenesis

The purpose of this study was to explore the effect and mechanism of Xihuang Pills on rats with precancerous lesions of the breast. Of 48 healthy female rats, 8 were randomly selected as blank group, and the other 40 were treated with 7,12-dimethylbenzanthracene(DMBA) combined with estrogen and progestin to establish a model of precancerous lesions of the breast. The successfully modeled rats were randomly divided into a model group, a tamoxifen group(1.8 mg·kg~(-1)·d~(-1)), a Xihuang Pills low-dose group(0.3 g·kg~(-1)·d~(-1)), a medium-dose group(0.6 g·kg~(-1)·d~(-1)) and a high-dose group(1.2 g·kg~(-1)·d~(-1)). After 30 days of admi-nistration, the histopathological changes of viscera and breast were observed by haematoxylin and eosin(HE) staining, and the visceral index was calculated. Enzyme linked immunosorbent assay(ELISA) was used to detect the contents of estradiol(E_2) and progesterone(P) in serum. The protein expressions of vascular endothelial growth factor(VEGF) and fibroblast growth factor 2(FGF2) were detected by immunohistochemistry. The protein expressions of VEGF, vascular endothelial growth factor receptor 2(VEGFR2), phosphorylated-vascular endothelial growth factor receptor 2(p-VEGFR2), B-cell lymphoma-2(Bcl-2), and Bcl-2 associated X protein(Bax) were detected by Western blot and the mRNA expressions of VEGF, FGF2, CXC-chemokine receptor 4(CXCR4), cysteine aspartic acid-specific protease(caspase-3), and stromal cell-derived factor 1(SDF-1) were detected by real-time polymerase chain reaction(RT-PCR). HE staining revealed that the model group had some liver and kidney damages and severe hyperplastic mammary tissue, while the Xihuang Pills high-dose group had mild hyperplasia. Compared with the model group, the Xihuang Pills groups had lo-wer ovarian coefficient(P<0.05 or P<0.01) and Xihuang Pills high-dose group had lower uterine coefficient(P<0.01). ELISA results showed that compared with the model group, expressions of E_2 and P in Xihuang Pills high-dose group were significantly decreased(P<0.05 or P<0.01). Immunohistochemistry, Western blot and RT-PCR indicated that compared with the conditions in the model group, the protein and mRNA expressions of VEGF and FGF2 in the Xihuang Pills groups were down-regulated(P<0.05 or P<0.01), and the protein expression of Bcl-2 was lowered(P<0.01); there was a decrease in the protein expressions of VEGFR2 and p-VEGFR2(P<0.01), a down-regulation in the mRNA expressions of CXCR4 and SDF-1(P<0.01), while an increase in the mRNA expression of caspase-3(P<0.01) in both Xihuang Pills medium-dose and high-dose groups; the protein expression of Bax in Xihuang Pills high-dose group was increased(P<0.01). The above results indicated that Xihuang Pills can effectively intervene in precance-rous lesions of the breast, and the mechanism may be related to the regulation of E_2 and P secretion as well as the inhibition of angiogenesis and chemokine receptor expression, thus controlling the occurrence of precancerous lesions of the breast in rats.
Rats ; Female ; Animals ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; Vascular Endothelial Growth Factor A/metabolism* ; Caspase 3 ; Vascular Endothelial Growth Factor Receptor-2 ; Fibroblast Growth Factor 2 ; Proto-Oncogene Proteins c-bcl-2 ; 9,10-Dimethyl-1,2-benzanthracene/toxicity* ; Precancerous Conditions ; Hyperplasia ; Receptors, Chemokine ; RNA, Messenger

OBJECTIVE: To observe the effect of electroacupuncture (EA) on vascular endothelial growth factor-C (VEGF-C), vascular endothelial growth factor receptor-3 (VEGFR-3), proinflammatory factors and apoptosis in myocardial tissue in mice with acute myocardial ischemia (AMI), and to explore the mechanism of EA for AMI. METHODS: Fifty male C57BL/6 mice were randomly divided into a sham operation group, a model group, an EA group, an inhibitor group and an inhibitor+EA group, 10 mice in each group. Except for the sham operation group, the mice in the remaining groups were intervented with ligation at the left anterior descending (LAD) coronary artery to establish AMI model. The mice in the sham operation group were intervented without ligation after thoracotomy. The mice in the EA group were intervented with EA at "Shenmen" (HT 7) and "Tongli" (HT 5), disperse-dense wave, 2 Hz/15 Hz in frequency, 1 mA in current intensity, 30 min each time, once a day, for 3 d. The mice in the inhibitor group were treated with intraperitoneal injection of SAR 131675 (12.5 mg•kg^-1•d^-1, once a day for 3 d). The mice in the inhibitor+EA group were injected intraperitoneally with SAR 131675 30 min before EA. The ECG before modeling, 30 min after modeling and 3 d after intervention was detected, and the ST segment displacement was recorded; after the intervention, the ELISA method was applied to measure the contents of serum creatine kinase isoenzyme (CK-MB), aspartate aminotransferase (AST) as well as tumor necrosis factor-α (TNF-α) and interleukin-23 (IL-23) in myocardial tissue; the HE staining method was used to observe the morphological changes of myocardial tissue; the immunofluorescence double labeling method was applied to measure the number of co-expression positive cells of VEGF-C/VEGFR-3 in myocardial tissue; the TUNEL method was used to detect the level of cardiomyocyte apoptosis; the Western blot method was applied to measure the protein expressions of VEGF-C, VEGFR-3, b-lymphoma-2 (Bcl-2), activated caspase-3 (Cleaved Caspase-3) and activated poly adenosine diphosphate ribose polymerase-1 (Cleaved PARP-1). RESULTS: Compared with the sham operation group, in the model group the ST segment displacement was increased (P<0.01); the contents of CK-MB, AST, TNF-α and IL-23 were increased (P<0.01); the arrangement of myocardial fibers was disordered, and interstitial inflammatory cell infiltration was obvious; the number of co-expression positive cells of VEGF-C/VEGFR-3 was decreased (P<0.01); the number of cardiomyocyte apoptosis was increased (P<0.01); the expressions of VEGF-C, VEGFR-3 and Bcl-2 were decreased (P<0.01); the expressions of Cleaved Caspase-3 and Cleaved PARP-1 were increased (P<0.01). Compared with the model group, in the EA group the ST segment displacement was decreased (P<0.01); the contents of CK-MB, AST, TNF-α, IL-23 were decreased (P<0.01); the severity of myocardial pathological injury was reduced; the number of co-expression positive cells of VEGF-C/VEGFR-3 was increased (P<0.01); the number of cardiomyocyte apoptosis was reduced (P<0.01); the expressions of VEGF-C, VEGFR-3 and Bcl-2 were increased (P<0.01); the expressions of Cleaved Caspase-3 and Cleaved PARP-1 were reduced (P<0.01). There was no significant difference in all the indexes between the model group and the inhibitor group (P>0.05). Compared with the model group, the protein expression of VEGF-C was increased in the inhibitor+EA group (P<0.01). Compared with the inhibitor group, in the EA group the ST segment displacement was decreased (P<0.01); the contents of CK-MB, AST, TNF-α, IL-23 were decreased (P<0.01); the severity of myocardial pathological injury was reduced; the number of co-expression positive cells of VEGF-C/VEGFR-3 was increased (P<0.05); the number of cardiomyocyte apoptosis was reduced (P<0.01); the expressions of VEGF-C, VEGFR-3 and Bcl-2 were increased (P<0.01); the expressions of Cleaved Caspase-3 and Cleaved PARP-1 were reduced (P<0.01). Compared with the inhibitor+EA group, all the indexes in the EA group were improved except the protein expression of VEGF-C (P<0.01). CONCLUSION EA could relieve the inflammatory reaction and apoptosis in AMI mice, and its mechanism may be related to activating VEGF-C/VEGFR-3 pathway and promoting lymphangion genesis.
Mice ; Male ; Animals ; Electroacupuncture ; Vascular Endothelial Growth Factor Receptor-3 ; Caspase 3 ; Vascular Endothelial Growth Factor C ; Tumor Necrosis Factor-alpha/genetics* ; Vascular Endothelial Growth Factor A/genetics* ; Poly(ADP-ribose) Polymerase Inhibitors ; Mice, Inbred C57BL ; Myocardial Ischemia/metabolism* ; Apoptosis ; Interleukin-23 ; Proto-Oncogene Proteins c-bcl-2

OBJECTIVE: Dexmedetomidine (DEX), the most specific α ₂-adrenergic receptor agonist widely used for its sedative and analgesic properties, has been reported to upregulate HIF-1α expression to protect hypoxic and ischemic tissues. However, it is largely unclear whether DEX can also upregulate Hypoxia-inducible factor-1 alpha (HIF-1α) expression and its downstream vascular endothelial growth factor-A (VEGFA) in cancer tissues with oxygen-deficient tumor microenvironment. METHODS: We used SMMC-7721 cells, MHCC97-H cells, and a mouse model of orthotopic hepatic carcinoma to explore the effect of DEX on angiogenesis and vasculogenic mimicry (VM) and its mechanism. Under normoxic (20% O ₂) and hypoxic (1% O ₂) conditions, DEX was used to intervene cells, and yohimbine was used to rescue them. RESULTS: The results showed that DEX promoted angiogenesis and VM in human liver cancer cells within a certain dose range, and the addition of yohimbine inhibited this effect. DEX could activate HIF-1α/VEGFA pathway, which was further verified by silencing HIF-1α. Consistently, in vivo results also showed that DEX can up-regulate HIF-1α/VEGFA expression, and enhance the number of VM channels and microvessel density (MVD). CONCLUSION We believe that HIF-1α/VEGFA might be an important signaling pathway by which DEX promotes angiogenesis and VM formation in human hepatocellular carcinoma, whereas α ₂-adrenergic receptor mediation might be the critical mechanisms.
Animals ; Humans ; Mice ; Adrenergic alpha-2 Receptor Agonists/pharmacology* ; Carcinoma, Hepatocellular ; Cardiovascular Physiological Phenomena ; Dexmedetomidine/pharmacology* ; Hypoxia ; Liver Neoplasms/drug therapy* ; Oxygen ; Tumor Microenvironment ; Vascular Endothelial Growth Factor A/genetics* ; Receptors, Adrenergic, alpha-2/metabolism*

Endothelial cells that form the inner layers of both blood and lymphatic vessels are important components of the vascular system and are involved in the pathogenesis of vascular and lymphatic diseases. Angiopoietin (Ang)-Tie axis in endothelial cells is the second endothelium-specific ligand-receptor signaling system necessary for embryonic cardiovascular and lymphatic development in addition to the vascular endothelial growth factor receptor pathway. The Ang-Tie axis also maintains vascular homeostasis by regulating postnatal angiogenesis, vessel remodeling, vascular permeability, and inflammation. Therefore, the dysfunction of this system leads to many vascular and lymphatic diseases. In light of the recent advances on the role of the Ang-Tie axis in vascular and lymphatic system-related diseases, this review summarizes the functions of the Ang-Tie axis in inflammation-induced vascular permeability, vascular remodeling, ocular angiogenesis, shear stress response, atherosclerosis, tumor angiogenesis, and metastasis. Moreover, this review summarizes the relevant therapeutic antibodies, recombinant proteins, and small molecular drugs associated with the Ang-Tie axis.
Angiopoietins ; Endothelial Cells/metabolism* ; Humans ; Lymphatic Diseases ; Lymphatic System/metabolism* ; Receptor, TIE-2/metabolism* ; Signal Transduction ; Vascular Endothelial Growth Factor A

OBJECTIVE: To analyze the expression and relationship of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR) in local skin tissues of pressure injury and investigate the possible mechanism of stage 3 pressure injury refractory wound. METHODS: Forty male SD rats were randomly divided into normal control group, compressed 3 d, 5 d, 7 d, and 9 d groups. Stage 3 pressure injury animal model were established by magnet compression. The morphology of skin was observed by HE staining. The expression of VEGF was detected by immunohistochemistry. The expression levels of HIF-1α, VEGF and KDR protein in skin tissue were detected by Western blot. One-way analysis of variance and LSD test were performed on the data. RESULTS: ①The HE results showed that compared with the normal control group, the epidermis of the compressed group was gradually thickened, the number of blood vessels was decreased, the collagen arrangement disordered and inflammatory cells infiltration were increased. ②Immunohistochemical results showed that the expression of VEGF protein in the 3 d group was significantly higher than that in the normal control group (P＜0.01). The expression of VEGF protein in the skin tissue of 5 d, 7 d and 9 d groups was lower than that in normal control group (P＜0.05). WB results were consistent with immunohistochemistry results. ③WB results showed that the expression of HIF-1α in the skin tissues of the rats in 3 d, 5 d and 7 d groups was higher than that in the normal control group (P＜0.01 or P＜0.05). The expression of KDR protein was lower than that of the normal control group (P＜0.05 or P＜0.01). CONCLUSION HIF-1α mediated reduction of VEGF and KDR protein expression and decreased tissue angiogenesis may be one of the important causes of chronic dysfunction of stage 3 pressure injury.
Animals ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Male ; Pressure ; adverse effects ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Skin ; injuries ; Vascular Endothelial Growth Factor A ; genetics ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; metabolism

BACKGROUNDRecombinant human-erythropoietin (rh-EPO) has therapeutic efficacy for premature infants with brain damage during the active rehabilitation and anti-inflammation. In the present study, we found that the rh-EPO was related to the promotion of neovascularization. Our aim was to investigate whether rh-EPO augments neovascularization in the neonatal rat model of premature brain damage through the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) signaling pathway.

METHODSPostnatal day 5 (PD5), rats underwent permanent ligation of the right common carotid artery and were exposed to hypoxia for 2 h. All the rat pups were randomized into five groups as follows: (1) control group; (2) hypoxia-ischemic (HI) group; (3) HI + LY294002 group; (4) HI + rh-EPO group; and (5) HI + rh-EPO + LY294002 group. The phospho-Akt protein was tested 90 min after the whole operation, and CD34, vascular endothelial growth factor receptor 2 (VEGFR2), and vascular endothelial growth factor (VEGF) were also tested 2 days after the whole operation.

RESULTSIn the hypoxic and ischemic zone of the premature rat brain, the rh-EPO induced CD34+ cells to immigrate to the HI brain zone (P < 0.05) and also upregulated the VEGFR2 protein expression (P < 0.05) and VEGF mRNA level (P < 0.05) through the PI3K/Akt (P < 0.05) signaling pathway when compared with other groups.

CONCLUSIONSThe rh-EPO treatment augments neovascularization responses in the neonatal rat model of premature brain damage through the PI3K/Akt signaling pathway. Besides, the endogenous EPO may exist in the HI zone of rat brain and also has neovascularization function through the PI3K/Akt signaling pathway.

Animals ; Animals, Newborn ; Antigens, CD34 ; metabolism ; Brain ; drug effects ; metabolism ; pathology ; Disease Models, Animal ; Erythropoietin ; genetics ; metabolism ; therapeutic use ; Female ; Humans ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; Neovascularization, Physiologic ; drug effects ; Phosphatidylinositol 3-Kinase ; metabolism ; Pregnancy ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; genetics ; metabolism ; therapeutic use ; Signal Transduction ; drug effects ; Vascular Endothelial Growth Factor A ; genetics ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

OBJECTIVEThis study aimed at investigating whether notoginsenoside R1 (R1), a unique saponin found in Panax notoginseng could promote angiogenic activity on human umbilical vein endothelial cells (HUVECs) and elucidate their potential molecular mechanisms. In addition, vascular restorative activities of R1 was assessed in a chemically-induced blood vessel loss model in zebrafish.

METHODSThe in vitro angiogenic effect of R1 was compared with other previously reported angiogenic saponins Rg1 and Re. The HUVECs proliferation in the presence of R1 was determined by cell proliferation kit II (XTT) assay. R1, Rg1 and Re-induced HUVECs invasion across polycarbonate membrane was stained with Hoechst-33342 and quantified microscopically. Tube formation assay using matrigelcoated wells was performed to evaluate the pro-angiogenic actions of R1. In order to understand the mechanism underlying the pro-angiogenic effect, various pathway inhibitors such as SU5416, wortmannin (wort) or L-Nω-nitro- L-arginine methyl ester hydrochloride (L-NAME), SH-6 were used to probe the possible involvement of signaling pathway in the R1 mediated HUVECs proliferation. In in vivo assays, zebrafish embryos at 21 hpf were pre-treated with vascular endothelial growth factor (VEGF) receptor kinase inhibitor II (VRI) for 3 h only and subsequently post-treated with R1 for 48 h, respectively. The intersegmental vessels (ISVs) in zebrafish were assessed for the restorative effect of R1 on defective blood vessels.

RESULTSR1 could stimulate the proliferation of HUVECs. In the chemoinvasion assay, R1 significantly increased the number of cross-membrane HUVECs. In addition, R1 markedly enhanced the tube formation ability of HUVECs. The proliferative effects of these saponins on HUVECs were effectively blocked by the addition of SU5416 (a VEGF-KDR/Flk-1 inhibitor). Similarly, pre-treatment with wort [a phosphatidylinositol 3-kinase (PI3K)-kinase inhibitor], L-NAME [an endothelial nitric oxide synthase (eNOS) inhibitor] or SH-6 (an Akt pathway inhibitor) significantly abrogated the R1 induced proliferation of HUVECs. In chemicallyinduced blood vessel loss model in zebrafish, R1 significantly rescue the damaged ISVs.

CONCLUSIONR1, similar to Rg1 and Re, had been showed pro-angiogenic action, possibly via the activation of the VEGF-KDR/Flk-1 and PI3K-Akt-eNOS signaling pathways. Our findings also shed light on intriguing pro-angiogenic effect of R1 under deficient angiogenesis condition in a pharmacologic-induced blood vessels loss model in zebrafish. The present study in vivo and in vitro provided scientific evidence to explain the ethnomedical use of Panax notoginseng in the treatment of cardiovascular diseases, traumatic injuries and wound healing.

Animals ; Blood Vessels ; pathology ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Collagen ; pharmacology ; Disease Models, Animal ; Drug Combinations ; Ginsenosides ; chemistry ; pharmacology ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; enzymology ; physiology ; Humans ; Laminin ; pharmacology ; Neovascularization, Physiologic ; drug effects ; Phosphatidylinositol 3-Kinases ; metabolism ; Protein Kinase Inhibitors ; pharmacology ; Proteoglycans ; pharmacology ; Proto-Oncogene Proteins c-akt ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism ; Zebrafish

OBJECTIVETo explore the impacts of erythropoietin on vascular endothelial growth factor receptor 2 (VEGFR2) by the extracellular signal-regulated kinase (ERK) signaling pathway in a neonatal rat model of periventricular white matter damage.

METHODSAll of postnatal day 4 rats were randomized into three groups: the sham group [without hypoxia-ischemia (HI)], the HI group (HI with saline administration), and the erythropoietin (EPO) group [HI with recombinant human erythropoietin (rh-EPO) administration]. Rat pups underwent permanent ligation of the right common carotid artery, followed by 6% O2 for 2 hours or sham operation and normoxic exposure. Immediately after the HI, rats received a single intraventricular injection of rh-EPO (0.6 IU/g body mass) or saline. ERK and phosphorylation-ERK were examined at 60 minutes and 90 minutes after operation, and VEGFR2 were detected at 2 and 4 days after operation by using Western blot.

RESULTSAt 60 minutes and 90 minutes after operation, the proteins of phosphorylation-ERK were significantly higher in HI rats than in the sham rats and significantly higher in HI+EPO rats than in the HI rats (P<0.05). Two days after operation, VEGFR2 was not significantly different between sham and HI rats. However, the proteins of VEGFR2 were increased after administration of rh-EPO (P<0.05). Four days after operation, the proteins of VEGFR2 were significantly higher in HI rats than in the sham rats and significantly higher in HI+EPO rats than in the HI rats (P<0.05).

CONCLUSIONEPO may regulate VEGFR2 expression by affecting the intracranial ERK signaling pathways.

Animals ; Animals, Newborn ; Disease Models, Animal ; Erythropoietin ; pharmacology ; Humans ; Hypoxia-Ischemia, Brain ; physiopathology ; MAP Kinase Signaling System ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; pharmacology ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism ; White Matter ; physiopathology