Astragaloside IV Improves Vasodilatation Function by Regulating the PI3K/Akt/eNOS Signaling Pathway in Rat Aorta Endothelial Cells.

Coronary heart disease (CHD) remains a major public health burden. Endothelial-dependent coronary artery vasoreactivity is a significant indicator of vascular function. Endothelial dysfunction is characterized by decreased nitric oxide (NO) bioavailability and predicts late cardiovascular events. Astragaloside IV (AGIV) is the main active component of the herb Astragalus membranaceus. Although it shows a significant protective effect against vascular endothelial dysfunction, the mechanisms of AGIV promoting the vascular dilation have not been elucidated. This study investigated the vasodilator effect of AGIV on rat aortic rings and the underlying effect of AGIV via the PI3K/Akt/eNOS signaling pathway. We measured the relaxation of isolated RARs after different concentrations of AGIV treatment. Rat aorta endothelial cells were cultured with different doses of AGIV, dimethylsulfoxide, and NG-nitro L-arginine methyl ester. The expression of phosphorylated (p)-Akt and -endothelial nitric oxide synthase (p-eNOS) were tested by Western blot analysis. The messenger (m)RNA expression of eNOS was quantified by real-time polymerase chain reaction. AGIV exerted a vasodilator effect on the aortic rings and increased the NO content in a concentration-dependent manner. The vasorelaxation was suppressed by an eNOS inhibitor. AGIV regulated the PI3K/Akt/eNOS signaling pathway via phosphorylation of Akt at Ser473 and dephosphorylation of eNOS at Thr495. The mRNA expression of eNOS was remarkably upregulated by AGIV. AGIV significantly induced the dilation of the aortic rings, leading to the vasodilator response by enhancing the eNOS release via the PI3K/Akt/eNOS signaling pathway.

Hyperbaric oxygen for experimental intracerebral haemorrhage: Systematic review and stratified meta-analysis.

OBJECTIVE: Hyperbaric oxygen (HBO) is widely used in treating various neurological diseases. However, HBO for treatment of intracerebral haemorrhage (ICH) remains controversial, in either animal or clinical studies. Therefore, we conducted this systematic review and meta-analysis on studies describing the efficacy of HBO in animal models of ICH. METHODS: Studies were identified by searching mainstream databases through November 2015. The efficacy of HBO in animal models of ICH was assessed by changes in the brain water content (BWC), neurobehavioural outcome (NO) or both. Subgroup analyses were performed according to different design characteristics. RESULTS: In total 15 studies met our inclusion criteria. HBO can reduce the BWC (-0.982, 95% CI, -1.148 to -0.817; P < 0.01; 57 comparisons), and improve NO (-0.767, 95% CI, -1.376 to -0.159; P < 0.01; eight comparisons). HBO was most effective in reducing BWC when given 72 h after ICH for a 4- to 5-day consecutive treatment at the chamber pressure of 3.0 atmosphere absolute. Efficacy was higher with phenobarbital anaesthesia, the blood infusion model and in rabbits. CONCLUSION: Although HBO was found to be effective in experimental ICH, additional confirmation is needed due to possible publication bias, poor study quality and the limited number of studies conducting clinical trials.

Buyang huanwu decoction promotes angiogenesis via vascular endothelial growth factor receptor-2 activation through the PI3K/Akt pathway in a mouse model of intracerebral hemorrhage.

BACKGROUND: Intracerebral hemorrhage (ICH) is a fatal subtype of stroke that lacks effective treatments. Angiogenesis following ICH is an important response mediating brain recovery and repair. Phosphorylation of vascular endothelial growth factor receptor 2 (pVEGFR2) via PI3K/Akt signaling plays a key role in mediating cellular processes involved in repair, such as mitogenesis, angiogenesis, and vascular permeability. This study aimed to investigate the potential effects of Buyang Huanwu Decoction (BYHWD), a traditional Chinese medicine formula, on angiogenesis by VEGFR2 activation through the phosphatidylinositol 3 kinase (PI3K)/Akt signaling pathway in a mouse model of ICH. METHODS: Adult male Kunming mice (n = 50) were randomly assigned into sham and ICH-operated groups and treated with one of the followings SU5416 (VEGFR2 inhibitor), BYHWT and BYHWT + SU5416. ICH was induced in mice by injecting collagenase (type VII) into the right globus pallidus of the mouse brain. BYHWD (4.36 g/kg) was administrated in mice by intragastric infusion. Neurological function was evaluated in mice by a modified Neurological Severity Scores (mNSS) as well as corner turn and foot-fault tests. Angiogenesis was examined by intraperitoneal injection of 5-bromodeoxyuridine (BrdU) in mice to quantify new brain vessel growth. SU5416 treatment and assessment of VEGFR2 phosphorylation as well as alterations in PI3K/Akt signaling were performed to determine whether the effect of BYHWD on angiogenesis was partly mediated by phosphorylation of VEGFR2 via the PI3K/Akt signaling pathway. RESULTS: We show that BYHWD treated mice exhibited (i) significantly better recovery from neurological dysfunction, (ii) increased BrdU(+) nuclei in vWF(+) dilated brain vessels and (iii) higher VEGFR2 phosphorylation immunoreactivity in brain microvessels (P <0.05), (iv) higher expression of PI3K and pAkt at the protein level (P <0.05) when compared to untreated ICH mice. These beneficial effects were reversed by SU5416 (P <0.05). CONCLUSIONS: BYHWD promoted neurological recovery and angiogenesis after ICH in mice by enhancing VEGFR2 phosphorylation through the PI3K/Akt signaling pathway.

Electroacupuncture improves recovery after hemorrhagic brain injury by inducing the expression of angiopoietin-1 and -2 in rats.

BACKGROUND: Angiopoietin (Ang) is one of the major effectors of angiogenesis, playing a critical role in neurovascular remodeling after stroke. Acupuncture has been widely used for treating stroke in China for a long time. Recently, we have demonstrated that electroacupuncture (EA) can accelerate intracerebral hemorrhage (ICH)-induced angiogenesis in rats. In the present study, we investigated the effect of EA on the expression of Ang-1 and Ang-2 in the brain after ICH. METHODS: ICH was induced by stereotactic injection of collagenase type VII into the right globus pallidus. Adult male Sprague-Dawley rats were randomized into the following four groups: sham-operation (SHAM), stroke-no electroacupuncture (SNE), stroke-EA at the Zusanli acupoint (SEZ), and stroke-EA at a nonacupoint (SEN). EA was applied to the bilateral Zusanli (ST36) acupoint in the SEZ group and a nonacupoint in the SEN group. The expression of Ang-1 and Ang-2 was evaluated by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Some Ang-1 and Ang-2 immunoreactive microvessels with a dilated outline were detected in the perihematomal tissues after ICH, and the vessels extended into the clot from the surrounding area since day 7. The expression of Ang-1 increased notably as long as 2 weeks after ICH, while Ang-2 immunoreactivity declined at about 7 days following a striking upregulation at 3 days. EA at the Zusanli (ST36) acupoint upregulated the expression of Ang-1 and Ang-2 at both the protein and mRNA levels. However, EA at a nonacupoint had little effect on the expression of Ang-1 and Ang-2. CONCLUSIONS: Our data suggest that EA at the Zusanli (ST36) acupoint exerts neuroprotective effects on hemorrhagic stroke by upregulation of Ang-1 and Ang-2.

Temporal profile of angiogenesis and expression of extracellular matrix-related genes in rat brains following experimental intracerebral hemorrhage.

BACKGROUND: Angiogenesis is essential for the repair process after intracerebral hemorrhage (ICH). METHODS: Given the importance of the extracellular matrix (ECM) in angiogenesis, we analysed the temporal profile of angiogenesis in rat brains on days 4, 7, and 21 after ICH. To this end, we compared the expression of ECM-related genes between ICH-induced and sham-operated groups using a complementary DNA (cDNA) array. We further measured protein expression using western blot and immunohistochemistry assays. Fluorescein isothiocyanate (FITC)-dextran was injected into the tail vein to examine the angioarchitecture in the perihematomal region. RESULTS: Among the 88 ECM-related genes, we identified 42, 50, and 38 genes that were significantly upregulated on days 4, 7, and 21 after ICH, respectively (P < 0.05). Particularly, collagens, integrins, and matrix metalloproteinases (MMPs) were significantly increased on day 4 post-ICH and continued to increase at the other time points. Western blot and immunohistochemistry analyses showed a comparable trend in the upregulation of MMPs. Compared to the sham group, FITC-dextran labelling demonstrated decreased perfusion and increased vascular permeability in the perihematomal region in the ICH group. Doxycycline, an MMP inhibitor, significantly reduced angiogenesis (P < 0.05). CONCLUSIONS: The results of this study indicate that MMPs are involved in modulating angiogenesis following ICH.

Chitosan Hydrogel Delivery System Containing Herbal Compound Functions as a Potential Antineuroinflammatory Agent.

Rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid) is an anthraquinone compound mainly isolated from the herbal medicine rhubarb. It possesses a wide spectrum of pharmacological effects. However, the lack of sustained release properties and the poor bioavailability hinder clinical transformation. Hydrogel-based drug delivery system provides an ideal carrier to improve the release control and the therapeutic efficacy of drugs. Herein, we present a chitosan hydrogel for the delivery of rhein. This rhein-chitosan hydrogel (CS-Rh gel) exhibited superior characteristics including mechanical strength, sustained release, and low toxicity. For medical application, the enzyme-linked immunosorbent assay and Western blot analyses indicated that CS-Rh gel significantly suppressed the production of proinflammatory cytokines including TNF-α and IL-1ß in lipopolysaccharide-induced BV2 cells. Additionally, CS-Rh gel blocked the neuroinflammation-related mitogen-activated protein kinase (JNK, ERK, and p38)-signaling pathways. Interestingly, these inhibitory effects at 48 h outperformed the pharmacologic actions at 24 h, showing that the CS-Rh gel exerted optimal sustained antineuroinflammation. This study highlights a novel chitosan hydrogel containing rhein used as a potential antineuroinflammatory agent.

Buyang Huanwu Decoction () Attenuates Glial Scar by Downregulating the Expression of Leukemia Inhibitory Factor in Intracerebral Hemorrhagic Rats.

OBJECTIVE: To evaluate the effect of Buyang Huanwu Decoction (, BYHWD) on glial scar after intracerebral hemorrhage (ICH) and investigate the underlying mechanism. METHODS: Collagenase type VII (0.5 U) was injected stereotaxically into right globus pallidus to induce ICH model. One hundred and twenty Sprague-Dawley rats were randomly divided into 3 groups according to a random number table, including normal group (n=40), ICH model group (n=40) and BYHWD group (n=40), respectively. After ICH, the rats in the BYHWD group were intragastrically administered with BYHWD (4.36 g/kg) once a day for 21 days, while the rats in ICH group were administered with equal volume of distilled water for 21 days, respectively. Double immunolabeling was performed for proliferating cell nuclear antigen (PCNA)+/glial fibrillary acidic protein (GFAP)+ nuclei. The expression of GFAP and leukemia inhibitory factor (LIF) was evaluated by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The astrocytes with hypertrophied morphology around the hematoma was observed on day 3 after ICH. The number of GFAP positive cells and GFAP mRNA levels increased notably on day 3 and reached the peak on day 14 post-ICH (P<0.01). PCNA+/GFAP+ nuclei were observed around the hematoma and reached the peak on day 14 post-ICH (P<0.01). In addition, LIF-positive astrocytes and LIF mRNA level in the hemorrhagic region increased significantly till day 14 post-ICH (P<0.01). However, BYHWD not only reduced the number of PCNA+/GFAP+ nuclei, but also decreased GFAP and LIF levels (P<0.05). CONCLUSIONS: BYHWD could attenuate ICH-induced glial scar by downregulating the expression of LIF in the rats.

Leukemia Inhibitory Factor Decreases Neurogenesis and Angiogenesis in a Rat Model of Intracerebral Hemorrhage.

Neurogenesis and angiogenesis can improve the neurologic function after intracerebral hemorrhage (ICH). Leukemia inhibitory factor (LIF) plays an important role in neurogenesis and angiogenesis. In this study, a rat model of autologous blood-induced ICH was used to evaluate the effect of LIF on the neurogenesis and angiogenesis following ICH. After ICH, LIF-positive neurons and dilated vessels were detected in the peri-hematomal region. It was found that LIF levels increased significantly and peaked 14 days after ICH induction. Double immunofluorescence confirmed that LIF was expressed in neurons and endothelial cells. ICH also led to increases of doublecortin (DCX)- and von Willebrand factor (vWF)-positive cells as well as proliferation of cell nuclear antigen (PCNA)+/DCX+ and PCNA+/vWF+ nuclei. All these ICH-induced increases were significantly attenuated by exogenous LIF infusion. These data suggested that LIF was a negative regulator of neurogenesis and angiogenesis after ICH.

2-Methoxyestradiol Inhibits Intracerebral Hemorrhage- Induced Angiogenesis in Rats.

AIM: Angiogenesis occurs after intracerebral hemorrhage (ICH). Hypoxia-inducible factor-1? (HIF-1?) is a critical regulator of angiogenesis. However, its role in the central nervous system remains controversial. 2-Methoxyestradiol (2ME2), a natural metabolite of estrogen, is known to inhibit HIF-1?. In the present study, we investigated the effect of 2ME2 in a rat model of ICH-induced angiogenesis. MATERIAL AND METHODS: Sprague-Dawley male rats (n=50) were randomly divided into 5 groups: Sham operated group; ICH; ICH+2ME2; and ICH+Vehicle groups. ICH model was induced by stereotactic injection of collagenase type VII into the right globus pallidus. 2ME2 or vehicle (10% dimethyl sulfoxide) was administered intraperitoneally 10 min after ICH. Angiogenesis and expression of HIF-1? was evaluated by immunohistochemistry, quantitative real time-reverse transcription polymerase chain reaction and western blot, respectively. RESULTS: Proliferating cell nuclear antigen (PCNA)-labeled nuclei were detected in cerebral endothelial cells (ECs) around the hematoma. The labeling peaked at 14 days post-ICH. HIF-1?-immunoreactive microvessels with dilated outline were detected in the perihematomal tissues. The vessels extended into the clot from the surrounding tissues from day 7 onwards. HIF-1? protein levels increased, while no change was observed in HIF-1? mRNA expression after ICH. 2ME2 decreased the PCNA-labeled nuclei in cerebral ECs and down-regulated the expression of HIF-1? protein as well, while it had little effect on the mRNA expression of HIF-1?. CONCLUSION: HIF-1? inhibitor, 2ME2, inhibited post-ICH angiogenesis by suppressing HIF-1? expression, thus exerting detrimental effects in ICH.

Xuefu Zhuyu decoction improves neurological dysfunction by increasing synapsin expression after traumatic brain injury.

Xuefu Zhuyu decoction has been used for treating traumatic brain injury and improving post-traumatic dysfunction, but its mechanism of action needs further investigation. This study established rat models of traumatic brain injury by controlled cortical impact. Rat models were intragastrically administered 9 and 18 g/kg Xuefu Zhuyu decoction once a day for 14 or 21 days. Changes in neurological function were assessed by modified neurological severity scores and the Morris water maze. Immunohistochemistry, western blot assay, and reverse-transcription polymerase chain reaction were used to analyze synapsin protein and mRNA expression at the injury site of rats. Our results showed that Xuefu Zhuyu decoction visibly improved neurological function of rats with traumatic brain injury. These changes were accompanied by increased expression of synaptophysin, synapsin I, and postsynaptic density protein-95 protein and mRNA in a dose-dependent manner. These findings indicate that Xuefu Zhuyu decoction increases synapsin expression and improves neurological deficits after traumatic brain injury.

Activation of the Notch-1 signaling pathway may be involved in intracerebral hemorrhage-induced reactive astrogliosis in rats.

OBJECTIVE Reactive astrogliosis, a key feature that is characterized by glial proliferation, has been observed in rat brains after intracerebral hemorrhage (ICH). However, the mechanisms that control reactive astrogliosis formation remain unknown. Notch-1 signaling plays a critical role in modulating reactive astrogliosis. The purpose of this paper was to establish whether Notch-1 signaling is involved in reactive astrogliosis after ICH. METHODS ICH was induced in adult male Sprague-Dawley rats via stereotactic injection of autologous blood into the right globus pallidus. N-[ N-(3,5-difluorophenacetyl)-l-alanyl]- S-phenylglycine t-butyl ester (DAPT) was injected into the lateral ventricle to block Notch-1 signaling. The rats' brains were perfused to identify proliferating cell nuclear antigen (PCNA)-positive/GFAP-positive nuclei. The expression of GFAP, Notch-1, and the activated form of Notch-1 (Notch intracellular domain [NICD]) and its ligand Jagged-1 was assessed using immunohistochemical and Western blot analyses, respectively. RESULTS Notch-1 signaling was upregulated and activated after ICH as confirmed by an increase in the expression of Notch-1 and NICD and its ligand Jagged-1. Remarkably, blockade of Notch-1 signaling with the specific inhibitor DAPT suppressed astrocytic proliferation and GFAP levels caused by ICH. In addition, DAPT improved neurological outcome after ICH. CONCLUSIONS Notch-1 signaling is a critical regulator of ICH-induced reactive astrogliosis, and its blockage may be a potential therapeutic strategy for hemorrhagic injury.

Plasma metabolomics profiles in rats with acute traumatic brain injury.

Traumatic brain injury (TBI) is a major cause of mortality and disability worldwide. We validated the utility of plasma metabolomics analysis in the clinical diagnosis of acute TBI in a rat model of controlled cortical impact (CCI) using gas chromatography/mass spectrometry (GC/MS). Thirty Sprague-Dawley rats were randomly divided into two groups of 15 rats each: the CCI group and sham group. Blood samples were obtained from the rats within the first 24 h after TBI injury. GC/MS measurements were performed to evaluate the profile of acute TBI-induced metabolic changes, resulting in the identification of 45 metabolites in plasma. Principal component analysis, partial least squares-discriminant analysis, orthogonal partial least square discriminant analysis using hierarchical clustering and univariate/multivariate analyses revealed clear differences in the plasma metabolome between the acute CCI group and the sham group. CCI induced distinctive changes in metabolites including linoleic acid metabolism, amino acid metabolism, galactose metabolism, and arachidonic acid metabolism. Specifically, the acute CCI group exhibited significant alterations in proline, phosphoric acid, ß-hydroxybutyric acid, galactose, creatinine, L-valine, linoleic acid and arachidonic acid. A receiver operating characteristic curve analysis showed that the above 8 metabolites in plasma could be used as the potential biomarkers for the diagnosis of acute TBI. Furthermore, this study is the first time to identify the galactose as a biomarker candidate for acute TBI. This comprehensive metabolic analysis complements target screening for potential diagnostic biomarkers of acute TBI and enhances predictive value for the therapeutic intervention of acute TBI.

Is the Chinese medicinal formula Guipi Decoction () effective as an adjunctive treatment for depression? A meta-analysis of randomized controlled trials.

OBJECTIVES: To evaluate the effectiveness and safety of Guipi Decoction (, GPD) as an adjunctive in the treatment of depression. METHODS: A review of all relevant studies retrieved from a search of the following databases were conducted without any language restriction: Excerpt Medica Database (EMBASE), PubMed, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI), VIP Information, Wanfang Data, and the Chinese Biomedical Literature Database. Papers published until February 2013 were taken into consideration. The analysis was performed using the Cochrane software Revman 5.1. RESULTS: Nine randomized controlled trials involving 620 patients with depression were included in this review. The meta-analysis revealed that compared with antidepressant therapy alone, treatment with a combination of GPD and an antidepressant drug signifificantly improved the symptoms of depression [weighted mean difference (WMD):-3.09; 95% confifidence interval (CI):-4.11 to-2.07] and increased the rates of effectiveness (OR: 4.75; 95% CI: 2.66-8.51) as well as recovery (OR: 1.73; 95% CI: 1.17-2.56). The adverse effects of GPD were not found to be signifificant in these studies. CONCLUSIONS: The fifindings of this meta-analysis were in keeping with the notion that GPD formulations were effective in the treatment of depression without causing any serious adverse effects. However, currently available evidence was of low quality and therefore inadequate to justify a strong recommendation of using GPD formulations in the management of depression.

Leukemia Inhibitory Factor Contributes to Reactive Astrogliosis via Activation of Signal Transducer and Activator of Transcription 3 Signaling after Intracerebral Hemorrhage in Rats.

Reactive astrogliosis has occurred after intracerebral hemorrhage (ICH). Leukemia inhibitory factor (LIF) can act as a modulator for glial gene expression. Signal transducer and activator of transcription 3 (STAT3) is a critical regulator of reactive astrogliosis. The present study tested whether endogenous LIF acted on ICH-induced reactive astrogliosis via the STAT3 signaling pathway. Rats were divided into three experimental groups: 1) Rats received either an ICH or a needle insertion (sham), 2) Rats received 100 ng LIF or an equal volume of phosphate-buffered saline (PBS) by direct infusion into the lateral ventricle (LV) after ICH, and 3) AG490 (0.25 mg/kg) was injected into the LV to block STAT3 signaling. Brains were perfused to identify proliferating cell nuclear antigen (PCNA)+/glial fibrillary acidic protein (GFAP)+nuclei. The expression of GFAP, LIF, LIF receptor (LIFR), glycoprotein 130 (gp130), and phospho-STAT3 (p-STAT3) was evaluated by immunohistochemistry and Western blot, respectively. After ICH, the number of the PCNA+/GFAP+ nuclei and the expression of GFAP, LIF, LIFR, gp130, and p-STAT3 were increased. Moreover, LIF increased the number of PCNA+/GFAP+ nuclei and the expression of GFAP, LIFR, gp130, and p-STAT3. The number of PCNA+/ GFAP+ nuclei and GFAP protein levels were attenuated markedly after inhibition of p-STAT3. Together, these data suggest that LIF contributes to ICH-related reactive astrogliosis via activation of STAT3 signaling.

Efficacy of deferoxamine in animal models of intracerebral hemorrhage: a systematic review and stratified meta-analysis.

Intracerebral hemorrhage (ICH) is a subtype of stroke associated with high morbidity and mortality rates. No proven treatments are available for this condition. Iron-mediated free radical injury is associated with secondary damage following ICH. Deferoxamine (DFX), a ferric-iron chelator, is a candidate drug for the treatment of ICH. We performed a systematic review of studies involving the administration of DFX following ICH. In total, 20 studies were identified that described the efficacy of DFX in animal models of ICH and assessed changes in the brain water content, neurobehavioral score, or both. DFX reduced the brain water content by 85.7% in animal models of ICH (-0.86, 95% CI: -.48- -0.23; P < 0.01; 23 comparisons), and improved the neurobehavioral score by -1.08 (95% CI: -1.23- -0.92; P < 0.01; 62 comparisons). DFX was most efficacious when administered 2-4 h after ICH at a dose of 10-50 mg/kg depending on species, and this beneficial effect remained for up to 24 h postinjury. The efficacy was higher with phenobarbital anesthesia, intramuscular injection, and lysed erythrocyte infusion, and in Fischer 344 rats or aged animals. Overall, although DFX was found to be effective in experimental ICH, additional confirmation is needed due to possible publication bias, poor study quality, and the limited number of studies conducting clinical trials.

Angiogenesis opens a way for Chinese medicine to treat stroke.

Based on the pathophysiology of the brain, advance in angiogenesis induced by stroke, and evidences of Chinese-medicine-mediated angiogenesis, the possibility to study the stroke-treating mechanism of Chinese medicine in angiogenesis was discussed. And regarding our previous work on angiogenesis modulated by qi-tonifying and stasis-eliminating therapy following intracerebral hemorrhage, we proposed some questions, which should be taken into account in the further work.

Thrombin-triggered angiogenesis in rat brains following experimental intracerebral hemorrhage.

OBJECT: Angiogenesis occurs after intracerebral hemorrhage (ICH). Thrombin mediates mitogenesis and survival in endothelial cells and induces angiogenesis. The present study aimed to clarify whether thrombin is involved in triggering ICH-related angiogenesis. METHODS: In the first part of the experiment, autologous blood (with or without hirudin) was injected to induce ICH. In the second part, rats received either 1 U (50 µl) thrombin or 50 µl 0.9% sterile saline. In both parts, 5-bromo-2-deoxyuridine (BrdU) was administered intraperitoneally. Brains were perfused to identify BrdU-positive/von Willebrand factor (vWF)-positive nuclei. The expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1) and Ang-2 was evaluated by immunohistochemistry and quantitative real-time reverse transcription polymerase chain reaction. RESULTS: After ICH, the number of BrdU-/vWF-positive nuclei increased until Day 14, and vessels positive for HIF-1α, VEGF, Ang-1, and Ang-2 were observed around the clot. Quantitative analysis showed that ICH upregulated expression of HIF-1α, VEGF, Ang-1, and Ang-2 notably compared with that in sham controls (p < 0.05). However, hirudin significantly inhibited these effects. After thrombin treatment, many BrdU-positive/vWF-positive nuclei and HIF-1α-, VEGF-, Ang-1- and Ang-2-positive vessels could be detected around the affected region. CONCLUSIONS: Thrombin can induce angiogenesis in rat brains and may be an important trigger for ICH-related angiogenesis.

Thrombin promotes the expression of thrombospondin-1 and -2 in a rat model of intracerebral hemorrhage.

Spontaneous intracerebral hemorrhage (ICH) is one of the most severe types of stroke. Thrombin has been reported to participate in brain repair following ICH and play an important role in angiogenesis. Our previous studies have shown that ICH induces angiogenesis in damaged rat brain, accompanied by upregulation of expression of thrombospondin (TSP)-1 and TSP-2. The aim of the present study was to investigate whether the expression of TSP-1 and TSP-2 was regulated by thrombin in rat brain following ICH. A rat model of ICH was induced by injection of autologous blood into the right globus pallidus (GP). Hirudin, a thrombin specific inhibitor, or thrombin was injected into the GP. Immunohistochemistry, quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) and western blot assays were applied. Results showed that ICH induced an increase in the expression of TSP-1 mRNA and TSP-2 mRNA after ICH, whereas hirudin significantly inhibited the expression of TSPs mRNA after ICH (P<0.05). In contrast, sole thrombin treatment in normal rats induced strong expression of TSP-1 or TSP-2 in the blood vessels around the damaged brain region when compared with those without thrombin treatment. Western blot analysis data confirmed that the protein levels of TSPs were significantly increased when compared with those in the sham control group (P<0.01). These findings support that thrombin positively regulates the expression of TSP-1 and TSP-2 after ICH, which may be involved in modulating angiogenesis in injured brains following ICH.