Tetramethylpyrazine Protects Against Early Brain Injury and Inhibits the PERK/Akt Pathway in a Rat Model of Subarachnoid Hemorrhage.

Neuronal apoptosis is a potentially fatal pathological process that occurs in early brain injury (EBI) after subarachnoid hemorrhage (SAH). There is an urgent need to identify effective therapeutics to alleviate neuronal apoptosis. Tetramethylpyrazine (TMP), as an important component of the Chinese traditional medicinal herb Ligusticum wallichii, has been widely used in China to treat cerebral ischemic injury and confer neuroprotection. In the present work, we investigate whether TMP can reduce EBI following SAH in rats, specifically via inactivating the PERK/Akt signaling cascade. One hundred twenty-five male Sprague-Dawley rats were used in the present study. TMP was administered by intravenous (i.v.) injection, and the Akt inhibitor MK2206 was injected intracerebroventricularly (i.c.v.). SAH grade, neurological scores, and brain water content were measured 24 h after SAH. Neuronal apoptosis was visualized by Fluoro-Jade C (FJC) staining. Western blotting was used to measure the levels of PERK, p-PERK, eIF2α, p-eIF2α, Akt, p-Akt, Bcl-2, Bax, and cleaved caspase-3. Our results showed that TMP effectively reduced neuronal apoptosis and improved neurobehavioral deficits 24 h after SAH. Administration of TMP reduced the abundance of p-PERK and p-eIF2α. In addition, TMP increased the p-Akt level and the Bcl-2/Bax ratio and decreased the level of cleaved caspase-3. The selective Akt inhibitor MK2206 abolished the anti-apoptotic effect of TMP at 24 h after SAH. Collectively, these results indicate that Akt-related anti-apoptosis through the PERK pathway is a major, potent mechanism of EBI. Further investigation of this pathway may provide a basis for the development of TMP as a clinical treatment.

Tetramethylpyrazine Protects Neurons from Oxygen-Glucose Deprivation-Induced Death.

BACKGROUND To explore the theoretical basis for protecting the brain from ischemic stroke with tetramethylpyrazine, we studied whether and how tetramethylpyrazine could protect neurons against the oxygen-glucose deprivation (OGD)-induced death and whether transient receptor potential cation channel, subfamily C, member 6 (TRPC6) was involved. MATERIAL AND METHODS Primary rat cortical neurons were cultured and an OGD model was established in the presence or absence of tetramethylpyrazine. Neuronal death was assessed by measuring the uptake of membrane-impermeable PI. Western blot analysis was used to determine the protein expressions of TRPC6 and caspase-3. The involvement of TRPC6 was tested via RNAi against TRPC6. RESULTS OGD-induced neuronal death was decreased by tetramethylpyrazine in a concentration-dependent manner. The expression of TRPC6 protein was decreased by OGD. Furthermore, downregulating TRPC6 by RNA interfering mimicked the effect of OGD in neuronal death. Tetramethylpyrazine attenuated OGD-induced TRPC6 downregulation in a tetramethylpyrazine concentration-dependent manner. However, these effects of tetramethylpyrazine on attenuating OGD-induced neuronal death were abolished by TRPC6 RNAi. CONCLUSIONS Tetramethylpyrazine can protect neurons from oxygen-glucose deprivation-induced death, possibly via TRPC6.

Clinical study on the treatment of primary trigeminal neuralgia by robot-assisted percutaneous balloon compression.

Background: C-arm-guided percutaneous puncture balloon compression alone has risk factors of puncture failure, complications, and poor prognosis. Robot-assisted PBC can effectively increase the one-time puncture success rate and improve the safety of the procedure. However, evidence on the superiority of robot-assisted PBC over C-arm-guided PBC alone remains relatively limited. Methods: Retrospective analysis The clinical data of 60 patients with trigeminal neuralgia aged 60 years or older in the Department of Neurosurgery of the Fourth Hospital of Harbin Medical University from January 2021 to October 2021. There were 29 males and 31 females, and the patients' ages ranged from 60 to 79 years, with an average of 71.63 ± 5.12 years. Two groups were divided according to the surgical method, the C-arm guidance-only group (30 cases, n = 30) and the robot-assisted group (30 cases, n = 30). The success rate of first puncture, total operation time, number of "pear-shaped" balloons, number of C-arm x-ray scans, and immediate postoperative relief rate were recorded in both groups, and follow-up was performed to evaluate the postoperative results and complications. The overall evaluation of postoperative results and complications was performed. Results: Intraoperative balloon compression was successfully completed in all 60 patients, and the first puncture success rate was higher in the robot-assisted group than in the simple C-arm group, with a significant difference between the two groups (P < 0.001). In terms of intraoperative balloon morphology, the number of "pear-shaped" balloons was higher in the PBC than in the C-arm-only PBC group, with a significant difference between the two groups (P < 0.005). The degree of immediate postoperative remission in the robotic group was 0 VAS score, which was not statistically significant in both groups (P > 0.05). By the final follow-up, the mean VAS score of the robot-assisted group was lower than that of the simple C-arm group, and both were statistically significant (P < 0.05); complications of masticatory muscle weakness or abnormal facial sensation occurred in both groups after surgery, but the number of cases in the robot-assisted group was less than that of the simple C-arm group. Conclusion: Robot-assisted PBC is better than PBC with a C-arm x-ray machine in terms of first puncture success rate, number of intraoperative balloon "pear-shaped" cases, number of C-arm x-ray scans and short-term efficacy.

Bioinformatic analysis of the potential molecular mechanism of PAK7 expression in glioblastoma.

The present study aimed to determine the potential molecular mechanisms underlying p21 (RAC1)­activated kinase 7 (PAK7) expression in glioblastoma (GBM) and evaluate candidate prognosis biomarkers for GBM. Gene expression data from patients with GBM, including 144 tumor samples and 5 normal brain samples, were downloaded. Long non­coding RNAs (lncRNAs) and messenger RNAs (mRNAs) were explored via re­annotation. The differentially expressed genes (DEGs), including differentially expressed mRNAs and differentially expressed lncRNAs, were investigated and subjected to pathway analysis via gene set enrichment analysis. The miRNA­lncRNA­mRNA interaction [competing endogenous RNA (ceRNA)] network was investigated and survival analysis, including of overall survival (OS), was performed on lncRNAs/mRNAs to reveal prognostic markers for GBM. A total of 954 upregulated and 1,234 downregulated DEGs were investigated between GBM samples and control samples. These DEGs, including PAK7, were mainly enriched in pathways such as axon guidance. ceRNA network analysis revealed several outstanding ceRNA relationships, including miR­185­5p­LINC00599­PAK7. Moreover, paraneoplastic antigen Ma family member 5 (PNMA5) and somatostatin receptor 1 (SSTR1) were the two outstanding prognostic genes associated with OS. PAK7 may participate in the tumorigenesis of GBM by regulating axon guidance, and miR­185­5p may play an important role in GBM progression by sponging LINC00599 to prevent interactions with PAK7. PNMA5 and SSTR1 may serve as novel prognostic markers for GBM.

The ß-SiC nanowires (~100 nm) induce apoptosis via oxidative stress in mouse osteoblastic cell line MC3T3-E1.

Silicon carbide (SiC), a compound of silicon and carbon, with chemical formula SiC, the beta modification ( ß-SiC), with a zinc blende crystal structure (similar to diamond), is formed at temperature below 1700°C. ß-SiC will be the most suitable ceramic material for the future hard tissue replacement, such as bone and tooth. The in vitro cytotoxicity of ß-SiC nanowires was investigated for the first time. Our results indicated that 100 nm long SiC nanowires could significantly induce the apoptosis in MC3T3-E1 cells, compared with 100 µm long SiC nanowires. And 100 nm long SiC nanowires increased oxidative stress in MC3T3-E1 cells, as determined by the concentrations of MDA (as a marker of lipid peroxidation) and 8-OHdG (indicator of oxidative DNA damage). Moreover, transmission electron microscopy (TEM) was performed to evaluate the morphological changes of MC3T3-E1 cells. After treatment with 100 nm long SiC nanowires, the mitochondria were swelled and disintegrated, and the production of ATP and the total oxygen uptake were also decreased significantly. Therefore, ß-SiC nanowires may have limitations as medical material.

Effects of polymorphisms in nucleotide excision repair genes on glioma risk in a Chinese population.

We performed a case-control study to assess the relationship between six single nucleotide polymorphisms (SNPs) of xeroderma pigmentosum complementation group F (XPF) on glioma risk in a Chinese population. The six SNPs were genotyped in 330 glioma cases and 652 cancer-free controls using a 384-well plate format on the Sequenom MassARRAY platform (Sequenom, San Diego, USA). Rs1800067 did not follow the Hardy-Weinberg equilibrium in the control group, and the genotype distributions differed significantly between the two groups for SNPs rs1800067 and rs2276466. For rs1800067, the variant genotype T/T was strongly associated with an increased risk of glioma when compared with the A/A genotype (OR=3.77, 95% CI=2.38-6.01). Individuals with the rs1800067 G allele had a relatively high risk of glioma in a dominant model (OR=3.47, 95% CI=2.26-5.37). The rs2276466 G/G genotype was significantly associated with a moderate increased risk of glioma (OR=1.82, 95% CI=1.10-3.02) in a codominant model, and variation of rs25489 was associated with a 1.31- and 1.78-fold glioma risk in dominant and recessive models, respectively. Our study is the first to identify polymorphisms in rs1800067 and rs2276466 as correlated with glioma susceptibility.

Effects of tetramethylpyrazine on nitric oxide/cGMP signaling after cerebral vasospasm in rabbits.

Tetramethylpyrazine (TMP), an ingredient of Chinese herbal Szechwan lovage rhizome, shows vasorelaxant effect. Cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) is associated with high mortality and morbidity. Here, we evaluated the effect of TMP in a model of CVS and sought to identify the underlying mechanisms of action. A rabbit SAH model was established by injection of the autoblood via cisterna magna. Cerebral blood flow and arterial diameter were measured by Transcranial Doppler (TCD) and Computed Tomography Angiography (CTA). Expression of eNOS and PDE-V in basilar artery (BA) was assessed by western blots. Levels of nitric oxide (NO) in plasma and cerebral spinal fluid, and of intra-endothelium Ca(2+) were measured. Significantly reduced diameter and accelerated blood flow velocity were detected in BAs of SAH animals (P<0.05 vs. sham group). Expression of eNOS and NO was increased, and PDE-V expression was reduced by TMP.TMP ameliorated cerebral vasospasm (P<0.05 vs. SAH group), and L-NAME (a NOS inhibitor) partly abrogated the effects of TMP. TMP induced a dose-dependent increase of intra-endothelium Ca(2+). The current results demonstrated that the vasorelaxant effect of TMP was at least in part via regulation of NO/cGMP signaling.