Xiaoming Lei

Baicalein Reduces the Invasion of Glioma Cells via Reducing the Activity of p38 Signaling Pathway

Baicalein, one of the major flavonids in Scutellaria baicalensis, has historically been used in anti-inflammatory and anti-cancer therapies. However, the anti-metastatic effect and related mechanism(s) in glioma are still unclear. In this study, we thus utilized glioma cell lines U87MG and U251MG to explore the effect of baicalein. We found that administration of baicalein significantly inhibited migration and invasion of glioma cells. In addition, after treating with baicalein for 24 h, there was a decrease in the levels of matrix metalloproteinase-2 (MMP-2) and MMP-9 expression as well as proteinase activity in glioma cells. Conversely, the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 was increased in a dose-dependent manner. Moreover, baicalein treatment significantly decreased the phosphorylated level of p38, but not ERK1/2, JNK1/2 and PI3K/Akt. Combined treatment with a p38 inhibitor (SB203580) and baicalein resulted in the synergistic reduction of MMP-2 and MMP-9 expression and then increase of TIMP-1 and TIMP-2 expression; and the invasive capabilities of U87MG cells were also inhibited. However, p38 chemical activator (anisomycin) could block these effects produced by baicalein, suggesting baicalein directly downregulate the p38 signaling pathway. In conclusion, baicalein inhibits glioma cells invasion and metastasis by reducing cell motility and migration via suppression of p38 signaling pathway, suggesting that baicalein is a potential therapeutic agent for glioma.

Resveratrol Attenuates the Blood-Brain Barrier Dysfunction by Regulation of the MMP-9/TIMP-1 Balance after Cerebral Ischemia Reperfusion in Rats

The collapse of the blood-brain barrier (BBB) is one of the fundamental pathophysiology changes during cerebral ischemia reperfusion injury. Resveratrol has been recently reported to reduce cerebral ischemic damage by regulating the matrix metalloproteinase-9 (MMP-9). But, more direct evidence for the explanation of the BBB protected by resveratrol against cerebral ischemia reperfusion is still lacking. Therefore, the present study was aimed to investigate the regulation of BBB integrity by resveratrol after cerebral ischemia reperfusion and to determine the role of the MMP-9 and its endogenous inhibitor TIMP-1 balance in this process. Cerebral ischemia was induced by middle cerebral artery occlusion in rats. The BBB function was evaluated by brain water content and the Evans blue dye extravasation; the activities of MMP-9 and TIMP-1 were detected by using gelatin zymography analysis, and cellular apoptosis was examined by TUNEL staining. We confirmed that resveratrol reduced the cerebral ischemia reperfusion damage, brain edema, and Evans blue dye extravasation. Moreover, we found that resveratrol improved the balance of MMP-9/TIMP-1 in terms of their expressions and activities. A TIMP-1 neutralizing antibody reversed those neuroprotective effects of resveratrol. In conclusion, resveratrol attenuated the cerebral ischemia by maintaining the integrity of BBB via regulation of MMP-9 and TIMP-1.

Neuroprotective effects of quercetin in a mouse model of brain ischemic/reperfusion injury via anti-apoptotic mechanisms based on the Akt pathway.

The present study provided experimental evidence for the neuroprotective effects of quercetin using a rat model of global brain ischemic/reperfusion (I/R) injury. Pre‑treatment with quercetin (5 or 10 mg/kg orally (p.o.); once daily) induced a dose‑dependent reduction in I/R‑induced hippocampal neuron cell loss, with 10 mg/kg/day being the lowest dose that achieved maximal neuroprotection. Administration of 10 mg/kg quercetin over at least 3 days prior to I/R was required to improve the survival rate of I/R rats. Fluorescence‑assisted cell sorting, hematoxylin and eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling indicated neuronal cell loss in the CA1 hippocampus. Rats that had undergone transient global cerebral ischemia for 15 min followed by 1 h of reperfusion exhibited a significant increase in reactive oxygen species (ROS) production in the hippocampus. The I/R‑induced ROS overproduction in the hippocampus at 1, 12 and 24 h following I/R was significantly decreased by quercetin pre‑treatment. Western blot analysis revealed that the neuroprotective effects of quercetin (5 and 10 mg/kg/day, p.o.) were associated with an upregulation of the I/R‑induced suppression of B‑cell lymphoma‑2 (Bcl‑2), Bcl extra large and survivin expression as well as phosphorylation of Bcl‑2‑associated death promoter. Furthermore, the neuroprotective effects of quercetin (5, 10 mg/kg/day) in the brain were associated with an upregulation of Akt signaling. These findings suggested that the inhibition of I/R‑induced brain injury by quercetin likely involves a transcriptional mechanism to enhance anti‑apoptotic signaling.

Tea polyphenols may attenuate the neurocognitive impairment caused by global cerebral ischemia/reperfusion injury via anti-apoptosis

Background/aims: Global cerebral ischemia/reperfusion (GCIR) may incur neurocognitive impairment. Tea polyphenols (TP) have strong anti-oxidant capacity. This study planned to investigate the protective effect of TP against the neurocognitive impairment caused by GCIR and its mechanism. Methods: One-stage anterior approach for cerebral four-vessel occlusion (4VO) was used to construct the GCIR model. Sprague Dawley rats were randomly classified into Sham group, GCIR group, and TP group (n = 50 per group). Besides receiving the same 4VO, the rats in TP group were treated with TP (6.4%) injection from the tail vein 30 minutes before cerebral ischemia. Morris water-maze test was used to evaluate the changes in space recognition and memory and open field activity test to assess the activity and motor function of rats. The cell apoptotic study in hippocampal CA1 region at specified time points (12, 24, 48, and 72 hours after surgery) was carried out by the flow cytometry, histology (hematoxylin and eosin staining), and immunohistochemical (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining) examinations. One-way analysis of variance and least significant difference t-test were used and statistical significance considered at P < 0.05. Results: Compared with the GCIR group, the TP group was significantly attenuated in the impairment of space recognition and memory caused by GCIR and so was the neuronal apoptosis in the hippocampal CA1 region (P < 0.05). Conclusion: TP may attenuate the impairment of space recognition and memory caused by GCIR via anti-apoptosis.

Protective effect of tea polyphenols on the blood-brain barrier

This study was to investigate the protective effects of tea polyphenols on the blood-brain barrier (BBB) of rats with global cerebral ischemia/reperfusion (GCIR) injury. Sprague Dawley rats underwent four-vessel occlusion to construct the model of GCIR. Half an hour before complete occlusion, they were treated with tea polyphenols (TP) (6.4%; 100 or 200 mg/kg) via tail intravenous injection. 24 h after reperfusion, BBB permeability was evaluated by measuring brain water content (BWC) and residual amount of Evan’s blue dye in cerebral tissue. In addition to this, MMP-9 and collagen IV protein expression in cerebral tissue were also detected using immunohistochemistry. ANOVA and SNK-q were used to do statistical analysis. Statistical significance was considered at P<0.05. Compared to the untreated, the TP-treated rats had significantly decreased BWC (P<0.05), decreased residual amount of Evan’s blue dye in cerebral tissue (P<0.05), down-regulated MMP-9 (P<0.05) and up-regulated collagen IV expression in brain tissue (P<0.05). It can be concluded from these findings that TP may reduce the MMP-9 mediated collagen IV degradation caused by GCIR to protect the BBB.

An optimal dose of tea polyphenols protects against global cerebral ischemia/reperfusion injury

Previous studies addressing the protection of tea polyphenols against cerebral ischemia/reperfusion injury often use focal cerebral ischemia models, and the optimal dose is not unified. In this experiment, a cerebral ischemia/reperfusion injury rat model was established using a modified four-vessel occlusion method. Rats were treated with different doses of tea polyphenols (25, 50, 100, 150, 200 mg/kg) via intraperitoneal injection. Results showed that after 2, 6, 12, 24, 48 and 72 hours of reperfusion, peroxide dismutase activity and total antioxidant capacity in brain tissue gradually increased, while malondialdehyde content gradually decreased after tea polyphenol intervention. Tea polyphenols at 200 mg/kg resulted in the most apparent changes. Terminal deoxynucleotidyl transferase-mediated nick end labeling and flow cytometry showed that 200 mg/kg tea polyphenols significantly reduced the number and percentage of apoptotic cells in the hippocampal CA1 region of rats after cerebral ischemia/reperfusion injury. The open field test and elevated plus maze experiments showed that tea polyphenols at 200 mg/kg strengthened exploratory behavior and reduced anxiety of cerebral ischemia/reperfusion injured rats. Experimental findings indicate that tea polyphenols protected rats against cerebral ischemia/reperfusion injury and 200 mg/kg is regarded as the optimal dose.

Dose determination of sufentanil for intravenous patient-controlled analgesia with background infusion in abdominal surgeries: A random study

Objectives Sufentanil has been widely used in epidural PCA, while its use in intravenous PCA has rarely been reported. Based on its use in target controlled infusion, we reckoned that the effect-site concentration of sufentanil would be steady if background infusion is given in intravenous PCA. This prospective, single center, randomized study with a three arm parallel group design aims to find out the appropriate dose of sufentanil when used in intravenous PCA with background infusion in abdominal surgeries. Methods Patients diagnosed with gastrointestinal cancer and consented to the study were recruited. The analgesia pump with one of three different doses of sufentanil (1.5, 2.0 or 2.5 μg/kg) was attached to the patient through peripheral venous line right after surgery. The primary endpoint was pain scale VAS up to 48 hours postoperatively. Results In our study 90 patients were analyzed. In group B (SF 2.0) and C (SF2.5), patients had better pain relief than in group A (SF 1.5). There was no difference between group B and C in pain intensity at rest. While in group C more patients got pain relived at activity than in group B. All three groups had low and similar incidence of adverse effects of sufentanil. Conclusion The dose 2.5 μg/kg of sufentanil with background infusion is preferred because of better pain alleviation at activity without increase of adverse effects up to 48 hours after surgery.

Bioinformatics analysis of microarray data to reveal the pathogenesis of brain ischemia

Brain ischemia leads to energy depletion, mitochondrial dysfunction and neuronal cell death. The present study was designed to identify key genes and pathways associated with brain ischemia. The gene expression profile GSE52001, including 3 normal brain samples and 3 cerebral ischemia samples, was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified using the limma package. Then functional and pathway enrichment analyses were performed by the MATHT tool. Protein-protein interaction (PPI) network, module selection and microRNA (miRNA)-target gene network were constructed utilizing Cytoscape software. A total of 488 DEGs were identified (including 281 upregulated and 207 downregulated genes). In the PPI network, Rac family small GTPase 2 (RAC2) had higher degrees. RAC2 was significantly enriched in the FcγR-mediated phagocytosis pathway. miR-29A/B/C had a higher degree in the miRNA-target gene network. Insulin like growth factor 1 (Igf1) was identified as the target gene for miR-29A/B/C. RAC2 may function in brain ischemia through mediating the FcγR-mediated phagocytosis pathway. Meanwhile, miR-29A/B/C and their targets gene Igf1 may serve important roles in the development and progression of brain ischemia.

TNIP1 alleviates hepatic ischemia/reperfusion injury via the TLR2-Myd88 pathway

Hepatic ischemia/reperfusion (I/R) injury induces oxidative stress, hepatocyte apoptosis, and release of inflammatory cytokines, which together causes liver damage and even organ dysfunction. TNF-α-induced protein 3-interacting protein 1 (TNIP1) reportedly decreases expression of genes associated with stress response and inflammation. Thus, we investigated the effects of TNIP1 on hepatic cells injury caused by hypoxia/reoxygenation (H/R). Reduced expression of TNIP1 was determined in I/R mice compared to normal mice. Then, TNIP1 transgene mice were used to determine the effects of TNIP1 on mice after treatment for I/R. In the normal transgene (NTG) group, serum liver damage markers alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and gamma glutamyl transferase (GGT) in I/R mice significantly increased compared to the sham-operated mice. However, in the TNIP1 transgene (TNIP1-TG) group, those levels in I/R mice were reduced than that in NTG mice. Additionally, cell viability and apoptosis in the hepatic cell line L02 were detected after H/R treatment, MTT assay showed that cell viability was inhibited after H/R treatment, but reversed after ad-TNIP1 transfection. Cell apoptosis also was inhibited after ad-TNIP1 transfection, as shown by the caspase-3 and caspase-9 levels and Bcl-2 and Bax values. Furthermore, TNIP1 overexpression also attenuated the inflammatory response of L02 cells after H/R treatment. Finally, treatment with TNIP1 reduced the elevated expression of TLR2, TLR4, and Myd88 after H/R injury, but overexpression of TLR4 reversed the effects of TNIP1. In conclusion, TNIP1 may protect H/R-induced hepatic cell injury by inhibiting the TLR4/Myd88 pathway.

Molecular mechanism of estrogen-mediated neuroprotection in the relief of brain ischemic injury

BackgroundThis study aimed to explore the molecular mechanism of estrogen-mediated neuroprotection in the relief of cerebral ischemic injury. The gene expression profiles were downloaded from Gene Expression Omnibus database, and differentially expressed genes (DEGs) were identified using limma package in R software. Further, DEGs were subjected to Gene Ontology (GO) cluster analysis using online Gene Ontology Enrichment Analysis Software Toolkit and to GO functional enrichment analysis using DAVID software. Using the Gene Set Analysis Toolkit V2, enrichment analysis of Kyoto Encyclopedia of Genes and Genomes pathways was performed. In addition, protein-protein interaction (PPI) network was constructed using STRING database, and submodule analysis of PPI network. Lastly, the significant potential target sites of microRNAs (miRNAs) were predicted using Molecular Signatures Database, and the function analysis of targets of predicted miRNA was also performed using DAVID software.ResultsIn total, 321 DEGs were screened in the estrogen-treated sample. The DEGs were mainly associated with intracellular signaling and metabolic pathways, such as calcium channel, calcineurin complex, insulin secretion, low-density lipoprotein reconstruction, and starch or sugar metabolism. In addition, GO enrichment analysis indicated an altered expression of the genes related to starch and sucrose metabolism, retinol metabolism, anti-apoptosis (eg., BDNF and ADAM17) and response to endogenous stimulus. The constructed PPI network comprised of 243 nodes and 590 interaction pairs, and four submodules were obtained from PPI network. Among the module d, four glutamate receptors as Gria4, Gria3, Grin3a and Grik4 were highlighted. Further, 5 novel potential regulatory miRNAs were also predicted. MIR-338 and MIR520D were closely associated with cell cycle, while the targets of MIR-376A and MIR-376B were only involved in cell soma.ConclusionsThe DEGs in estrogen-treated samples are closely associated with calcium channel, glutamate induced excitotoxicity and anti-apoptotic activity. In addition, some functionally significant DEGs such as BDNF, ADAM17, Gria4, Gria3, Grin3a, Grik4, Gys2 and Ugtla2, and new miRNAs like MIR-338 and MIR-376A were identified, which may serve as potential therapeutic targets for the effective treatment of cerebral ischemic injury.