Long-term exposure to cadmium disrupts neurodevelopment in mature cerebral organoids.

Cadmium (Cd) is a pervasive environmental pollutant. Increasing evidence suggests that Cd exposure during pregnancy can induce adverse neurodevelopmental outcomes. However, due to the limitations of neural cell and animal models, it is challenging to study the developmental neurotoxicity and underlying toxicity mechanism of long-term exposure to environmental pollutants during human brain development. In this study, chronic Cd exposure was performed in human mature cerebral organoids for 49 or 77 days. Our study found that prolonged exposure to Cd resulted in the inhibition of cerebral organoid growth and the disruption of neural differentiation and cortical layer organization. These potential consequences of chronic Cd exposure may include impaired GFAP expression, a reduction in SOX2+ neuronal progenitor cells, an increase in TUJ1+ immature neurons, as well as an initial increase and a subsequent decrease in both TBR2+ intermediate progenitors and CTIP2+ deep layer cortical neurons. Transcriptomic analyses revealed that long-term exposure to Cd disrupted zinc and copper ion homeostasis through excessive synthesis of metallothionein and disturbed synaptogenesis, as evidenced by inhibited postsynaptic protein. Our study employed mature cerebral organoids to evaluate the developmental neurotoxicity induced by long-term Cd exposure.

Purification and Identification of Novel Antioxidant Peptides from Hydrolysates of Peanuts (Arachis hypogaea) and Their Neuroprotective Activities.

Peanut (Arachis hypogaea) peptides have various functional activities and a high utilization value. This study aims to isolate and characterize antioxidant peptides from peanut protein hydrolysates and further evaluate their neuroprotection against oxidative damage to PC12 cells induced by 6-hydroxydopamine (6-OHDA). After the peanut protein was hydrolyzed with pepsin and purified using ultrafiltration and gel chromatography, six peptides were identified and sequenced by high-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Out of these six peptides, Pro-Gly-Cys-Pro-Ser-Thr (PGCPST) exhibited a desirable antioxidant capacity, as determined using the 1,1-diphenyl-2-picrylhydrazyl, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, and hydroxyl radical scavenging assays. Moreover, our results indicated that the peptide PGCPST effectively increased the cell viability and reduced the cell apoptosis in 6-OHDA-induced PC12. RNA sequencing further showed that the neuroprotective effect of the peptide PGCPST was mediated via sphingolipid metabolism-related pathways. With further research efforts, the peptide PGCPST was expected to develop into a new neuroprotective agent.

An exploratory transmission mode of HIV/AIDS among older people based on data from multiple sources in China.

The HIV/AIDS cases and proportion in older people are continuously and rapidly increasing in China, especially in males. However, the transmission mechanism is not well understood. This study aims to explore the transmission mechanism of HIV/AIDS and potential ways to prevent or control HIV/AIDS transmission in a city in southwestern China. Data from multiple sources, including HIV/AIDS case reports in 2010-2020, a survey of HIV/AIDS cases in 2020, and sentinel surveillance data of female sex workers (FSWs) in 2016-2020 were analyzed. We explored the transmission mechanism of HIV/AIDS cases aged 50 years and older. In this city, the number of newly reported HIV/AIDS cases aged 50 years and older increased from 2010 to 2019, and decreased in 2020. The number of male and female cases aged 50 years and older both increased rapidly in 2017-2019, though the number of male cases was larger than that of female. The survey data showed that 84.7% of older male cases reported commercial sexual behavior, among whom 87.7% reported never using condom and 37.6% reported more than 10 times of commercial sexual behaviors in 1 year. In terms of price of sexual behavior, 68.3% of older male cases sought low-tier FSWs among whom the HIV/AIDS positive rate was 5.4% from the sentinel surveillance data. These results suggested HIV transmission between older men and low-tier FSWs through commercial sexual behavior. Among female cases aged 50 years and older, most reported non-marital and non-commercial heterosexual (60.5%) or regular sexual partner (31.4%) transmission, suggesting that they were infected by their spouse/regular sexual partner. Data of matched couples showed that most male cases had both marital sexual behavior and commercial sexual behavior, or acquired HIV through commercial sexual behavior, while most female cases had only marital sexual behavior. Based on these findings, we proposed a transmission mode of that local older male people and FSWs are transmitting bilaterally through commercial sexual behavior, and local older male people are spreading to local older female people through spouse or regular sexual partner route. By studying data from multiple sources, we explored the HIV transmission mode among older people. In the meantime, we found that marital status had a different impact on male and female old people in their sex behaviors.

Analysis on plausible factors related to the prognosis of stage IV esophageal cancer.

To investigate factors related to poor prognosis of patients with stage IV esophageal cancer and to provide some bases on which proper therapeutic schemes could be formulated for stage IV esophageal cancer patients with performance status (PS) score between 0 and 2.Clinical data of 60 patients with stage IV esophageal cancer were retrospectively analyzed, and the relationships of clinical characteristics and therapeutic methods with patients' prognosis were explored. Univariate analysis on factors possibly affecting the prognosis of patients with stage IV esophageal cancer was performed using Log-rank test, and independent risk factors for the prognosis were estimated in multivariate Cox regression analysis through embracing variables which showed statistical significance in univariate analyses.According to univariate analysis results, nutritional status, anemia, therapeutic method, esophageal stent, and visceral metastasis were main influencing factors for the prognosis of stage IV esophageal cancer (P < .05). While in multivariate Cox regression analysis, visceral metastasis was revealed to be an independent risk factor for poor prognosis in patients with stage IV esophageal cancer.Visceral metastasis is an independent risk factor for poor prognosis in patients with stage IV esophageal cancer. Optimizing therapeutic modes according to with or without combined visceral metastasis possesses certain clinical significance in prolonging survival time and in improving the quality of life among patients with stage IV esophageal cancer.

Diagnosis and surgical treatment of sporadic meningioangiomatosis.

OBJECTIVE: To discuss the clinical characteristics, radiological features, surgical treatment and prognosis of sporadic meningioangiomatosis (MA). METHODS: We retrospectively analyzed the medical records of ten histopathologically confirmed MA patients who were treated in the Department of Neurosurgery of Huashan hospital from 2002 to 2011. All of the patients presented with symptomatic seizure attacks before craniotomy surgeries. Magnetic resonance imaging (MRI) and/or computed tomography (CT) were the main radiological examination for preoperative diagnosis of all cases. RESULTS: All patients underwent craniotomy surgeries with gross total resections (GTRs) of the MA lesions. Postoperative follow-ups range from 8 to 108 months, in average 42.7 months, median 40.5 months. No radiological recurrence can be found in any case. Eight patients (80.0%) have achieved total symptomatic remission after surgeries (one of them underwent delayed remission), while two (20.0%) are still suffering from seizure attacks infrequently under several antiepileptic drugs (AEDs). CONCLUSION: Although MA cases are quite rare and usually misdiagnosed presurgically, a correct preoperative diagnosis, at least a differential diagnosis, can be rationally achieved via a triad of patients' ages, symptomatic seizure attacks and radiological features (both CT and MR). MA is curable and the prognosis is excellent since most patients became free of seizure and recurrence after surgical treatments.

Spectroscopic analyses on ROS generation catalyzed by TiO2, CeO2/TiO2 and Fe2O3/TiO2 under ultrasonic and visible-light irradiation.

In this work, the TiO2, CeO2/TiO2 and Fe2O3/TiO2 powders were irradiated, respectively, by ultrasound and visible-light, and the generation of reactive oxygen species (ROS) were estimated by the method of Oxidation-Extraction Photometry (OEP). That is, the 1,5-diphenyl carbazide (DPCI) can be oxidized by generated ROS into 1,5-diphenyl carbazone (DPCO), which can be extracted by mixed solvent of benzene and carbon tetrachloride. The DPCO extract liquor displays an obvious absorbance at 563 nm wavelength. In addition, some influencing factors, such as (ultrasonic or visible-light) irradiation time, catalyst addition amount and DPCI concentration, on the generation of ROS were also reviewed. The results indicated that the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and catalyst addition amount. Moreover, the displayed quantities of ROS are also related with DPCI concentration. And then, several radical scavengers were used to determine the kinds of the generated ROS. At last, the researches on the sonocatalytic and photocatalytic degradation of several organic dyes have also been performed. It is wished that this paper might offer some important subjects for broadening the applications of sonocatalytic and photocatalytic technologies in future environment treatment.

Intracranial clear cell meningioma in two children with blood relations: two case reports and literature review.

Intracranial clear cell meningioma (CCM) is very rare and often has an aggressive clinical course. The predilection site of intracranial CCM in children was cerebellopontine angle where represents challenging tumor resection because of the vicinity of brainstem, vertebral artery, and lower cranial nerve. Therefore, special consideration is required for this tumor.We report two cases with intracranial CCM in a family and reviewed the literature concerning pediatric intracranial CCM. Case 1 is a 4-year-old boy with a tumor at the right posterior fossa. Case 2 is an 8-year-old boy with a left basilar region tumor. Gross total resection and subtotal resection was achieved in case 1 and case 2, respectively. Case 1 had no tumor recurrence at 12 months after the operation. Case 2 received cyber-knife radiosurgery (CKS) after subtotal resection at 4 months, and the residual tumor had gradually shrunk. Comprehensive chromosomal number aberrations in both patients were revealed by array-comparative genomic hybridization, and loss of neurofibromatosis 2 (NF2) gene was the common genetic abnormality in the two patients.To the best of our knowledge, this is the first report concerned two patients with CCM in a family, and the findings in this article suggest that CKS is a safe and effective adjuvant therapy for residual CCM after operation and NF2 gene mutation plays a role in tumorigenesis of pediatric intracranial CCM.

Spectroscopic analyses on sonocatalytic damage to bovine serum albumin (BSA) induced by ZnO/hydroxylapatite (ZnO/HA) composite under ultrasonic irradiation.

ZnO/hydroxylapatite (ZnO/HA) composite with HA molar content of 6.0% was prepared by the method of precipitation and heat-treated at 500°C for 40min and was characterized by powder X-ray diffraction (XRD). The sonocatalytic activities of ZnO/HA composite was carried out through the damage of bovine serum albumin (BSA) in aqueous solution. Furthermore, the effects of several factors on the damage of BSA molecules were evaluated by means of UV-vis and fluorescence spectra. Experimental results indicated that the damage degree of BSA aggravated with the increase of ultrasonic irradiation time, irradiation power and ZnO/HA addition amount, but weakened with the increase of solution acidity and ionic strength. In addition, the damage site to BSA was also studied by synchronous fluorescence technology and the damage site was mainly at tryptophan (Trp) residue. This paper provides a valuable reference for driving sonocatalytic method to treat tumor in clinic application.

Spectrometry researches on interaction and sonodynamic damage of riboflavin (RF) to bovine serum albumin (BSA).

In this paper, the riboflavin (RF) was used to study the interaction and sonodynamic damage to bovine serum albumin (BSA) by fluorescence and UV-vis spectroscopy. The results showed that the RF could efficiently bind to BSA in aqueous solution. Under ultrasonic irradiation, the RF could obviously damage the BSA. In addition, synchronous fluorescence spectroscopy revealed that the RF showed more accessible to tryptophan (Trp) residues than to tyrosine (Tyr) residues. Also, it damaged Trp residues more seriously than Tyr residues under ultrasonic irradiation. At last, the generation of reactive oxygen species (ROS) in sonodynamic process was estimated by the method of Oxidation-Extraction Spectrometry (OES). And then, several radical scavengers were used to determine the kind of ROS. It was found that at least the singlet oxygen ((1)O(2)) and hydroxyl radicals (*OH) were generated.

Spectroscopic analyses on interaction of Amantadine-Salicylaldehyde, Amantadine-5-Chloro-Salicylaldehyde and Amantadine-o-Vanillin Schiff-Bases with bovine serum albumin (BSA).

In this work, three Tricyclo [3.3.1.1(3,7)] decane-1-amine (Amantadine) Schiff-Bases, Amantadine-Salicylaldehyde (AS), Amantadine-5-Chloro-Salicylaldehyde (AS-5-C) and Amantadine-o-Vanillin (AS-o-V), were synthesized by direct heating reflux method in ethanol solution and characterized by infrared spectrum and elementary analysis. Fluorescence quenching was used to study the interaction of these Amantadine Schiff-Bases (AS, AS-5-C and AS-o-V) with bovine serum albumin (BSA). According to fluorescence quenching calculations the bimolecular quenching constant (K(q)), apparent quenching constant (K(SV)), effective binding constant (K(A)) and corresponding dissociation constant (K(D)), binding site number (n) and binding distance (r) were obtained. The results show that these Amantadine Schiff-Bases can obviously bind to BSA molecules and the binding strength order is AS

Detection of reactive oxygen species (ROS) generated by TiO2(R), TiO2(R/A) and TiO2(A) under ultrasonic and solar light irradiation and application in degradation of organic dyes.

In the present work, the rutile, anatase and mixed (rutile and anatase) crystal phase TiO(2) powders were irradiated by ultrasound and solar light, respectively, and the generation of reactive oxygen species (ROS) were detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). The DPCO can be extracted by the mixed solvent of benzene and carbon tetrachloride and the extract liquors display an obvious absorption peak around 563nm. In addition, the influences of (ultrasonic or solar light) irradiation time, TiO(2) addition amount and DPCI concentration on the quantities of generated ROS were also reviewed. The kinds of generated ROS were determined by using several radical scavengers. At last, the researches on the sonocatalytic and photocatalytic degradation of several organic dyes were also performed. It is wished that this paper might offer some important subjects for broadening the applications of sonocatalytic and photocatalytic technologies.

Spectroscopic studies on interaction and sonodynamic damage of metallochlorophyllin (Chl-M (M=Fe, Zn and Cu)) to protein under ultrasonic irradiation.

In this paper, the chlorophyll derivatives, metallochlorophyllin (Chl-M) (M=Fe, Zn and Cu) including chlorophyllin iron (Chl-Fe), chlorophyllin zinc (Chl-Zn) and chlorophyllin copper (Chl-Cu), were adopted as sonosensitizers to combine with ultrasonic irradiation, and the sonodynamic damage of bovine serum albumin (BSA) was investigated. At first, the interaction of Chl-M with BSA was studied by fluorescence spectroscopy. The results show that the quenching mechanism belongs to a static process and among them the affinity of Chl-Fe to BSA is the most obvious. Then, some influence factors on the sonodynamic damage of BSA molecules in the presence of Chl-M under ultrasonic irradiation were also studied. Synchronous fluorescence spectra show that the binding and damage sites of Chl-M to BSA molecule are mainly on the tryptophan (Trp) residues. The generation of ROS in Chl-M sonodynamic process is estimated by the method of Oxidation-Extraction Spectrometry (OEP). This paper may offer some valuable references for the study of the sonodynamic activity of Chl-M and the effect of the central metals. Synchronously, it contributes to the application of Chl-M in SDT for tumor treatment.

Oxidation-extraction spectrometry of reactive oxygen species (ROS) generated by chlorophyllin magnesium (Chl-Mg) under ultrasonic irradiation.

In order to examine the mechanism and process of sonodynamic reaction, the chlorophyllin magnesium (Chl-Mg) acting as a sonosensitizer was irradiated by ultrasound, and the generation of reactive oxygen species (ROS) were detected by the method of oxidation-extraction spectrometry (OES). That is, under ultrasonic irradiation in the presence of Chl-Mg, the 1,5-diphenyl carbazide (DPCI) is oxidized by generated ROS into 1,5-diphenyl carbazone (DPCO), which can be extracted by mixed organic solvent and display a obvious visible absorption at 563 nm wavelength. Besides, the generation conditions of ROS were also reviewed. The results demonstrated that the quantities of generated ROS increased with the increase of ultrasonic irradiation time, Chl-Mg concentration and DPCI concentration. Finally, several radical scavengers (l-Histidine (His), 2,6-Di-tert-butyl-methylphenol (BHT) and Vitamin C (VC)) were used to determine the kind of the generated ROS. It was found that at least the hydroxyl radical (OH) and singlet oxygen (1O2) were generated in the presence of Chl-Mg under ultrasonic irradiation. It is wish that this paper might offer some valuable references for the study on the mechanism of SDT and the application of Chl-Mg in tumor treatment.

Spectroscopic analyses on interaction of o-Vanillin-D-Phenylalanine, o-Vanillin-L-Tyrosine and o-Vanillin-L-Levodopa Schiff Bases with bovine serum albumin (BSA).

In this work, three o-Vanillin Schiff Bases (o-VSB: o-Vanillin-D-Phenylalanine (o-VDP), o-Vanillin-L-Tyrosine (o-VLT) and o-Vanillin-L-Levodopa (o-VLL)) with alanine constituent were synthesized by direct reflux method in ethanol solution, and then were used to study the interaction to bovine serum albumin (BSA) molecules by fluorescence spectroscopy. Based on the fluorescence quenching calculation, the bimolecular quenching constant (K(q)), apparent quenching constant (K(sv)), effective binding constant (K(A)) and corresponding dissociation constant (K(D)) as well as binding site number (n) were obtained. In addition, the binding distance (r) was also calculated according to Foster's non-radioactive energy transfer theory. The results show that these three o-VSB can efficiently bind to BSA molecules, but the binding array order is o-VDP-BSA>o-VLT-BSA>o-VLL-BSA. Synchronous fluorescence spectroscopy indicates that the o-VDP is more accessibility to tryptophan (Trp) residues of BSA molecules than to tyrosine (Tyr) residues. Nevertheless, the o-VLT and o-VLL are more accessibility to Tyr residues than to Trp residues.

Detection and comparison of reactive oxygen species (ROS) generated by chlorophyllin metal (Fe, Mg and Cu) complexes under ultrasonic and visible-light irradiation.

In this paper, in order to examine the mechanisms of sonodynamic and photodynamic reactions, the chlorophyllin metal (Chl-M (M=Fe, Mg and Cu)) complexes were irradiated by ultrasound (US) and visible-light (VL), respectively, and the generation of reactive oxygen species (ROS) were detected by the method of Oxidation-Extraction Spectrometry (OES). That is, the 1,5-diphenyl carbazide (DPCI) is oxidized by the generated ROS into 1,5-diphenyl carbazone (DPCO), which can display a various visible absorption around 563 nm wavelength. Besides, some influence parameters on the generation of ROS were also reviewed. The results demonstrated an apparent synergistic effect of Chl-M and ultrasonic or visible-light irradiation for the generation of ROS. Moreover, the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and Chl-M (M=Fe, Mg and Cu) concentration. Finally, several quenchers were used to determine the kind of the generated ROS. It is wished that this paper might offer some valuable references for the study on the sonodynamic therapy (SDT) and photodynamic therapy (PDT) mechanisms and the application of Chl-M in tumor treatment.

Preoperative evaluation of neurovascular relationships for microvascular decompression in the cerebellopontine angle in a virtual reality environment.

OBJECT: In this paper the authors' goal was to evaluate the feasibility and efficacy of a virtual reality (VR) system in preoperative planning for microvascular decompression (MVD) procedures treating idiopathic trigeminal neuralgia and hemifacial spasm. The system's role in surgical simulation and training was also assessed. METHODS: Between May 2008 and April 2009, the authors used the Dextroscope system to visualize the neurovascular complex and simulate MVD in the cerebellopontine angle in a VR environment in 16 patients (6 patients had trigeminal neuralgia and 10 had hemifacial spasm). Reconstructions were carried out 2-3 days before MVD. Images were printed in a red-blue stereoscopic format for teaching and discussion and were brought into the operating room to be compared with real-time intraoperative findings. RESULTS: The VR environment was a powerful aid for spatial understanding of the neurovascular relationship in MVD for operating surgeons and trainees. Through an initial series of comparison/confirmation experiences, the senior neurosurgeon became accustomed to the system. He could predict intraoperative problems and simulate surgical maneuvering, which increased his confidence in performing the procedure. CONCLUSIONS: The Dextroscope system is an easy and rapid method to create a stereoscopic neurovascular model for MVD that is highly concordant with intraoperative findings. It effectively shortens the learning curve and adds to the surgeon's confidence.

Inflammatory reaction after focal cerebral ischemia in mouse.

BACKGROUND: In response to the inflammatory reaction, circulating leukocytes aggregate and adhere to the endothelial cells and eventually pervade into tissues, resulting in cell damage. This study was to detect the inflammatory reactions in mouse focal cerebral ischemia and their distinct characteristics in the ischemic basal ganglia and surrounding cortex. METHODS: Mice were subjected to permanent occlusion of the left middle cerebral artery (MCAO) by introducing a suture for 2 to 120 hours. The expression of intercellular adhesion molecule 1 (ICAM-1) and Mac-1 was determined immunohistochemically. The myeloperoxidase (MPO) activity of the ischemic regions was measured. RESULTS: Four hours after MCAO, the number of ICAM-1 positive vessels in the ischemic basal ganglia increased (9.2 +/- 2.8 per mm(2)), peaked at 48 hours (29.6 +/- 4.8 per mm(2)), and decreased after 72 hours. In the ischemic cortex, the number increased rapidly 4 hours after MCAO (19.4 +/- 6.1 per mm(2)), peaked at 48 hours (44.4 +/- 16.8 per mm(2)), and declined after 72 hours. Mac-1 positive cells were seen in the ischemic basal ganglia (3.4 +/- 1.2 per mm(2)) 12 hours after MCAO, peaked after 48 hours (20.2 +/- 6.3 per mm(2)), and decreased after 72 hours. In the ischemic cortex, however, the number increased 4 hours after MCAO (4.3 +/- 1.7 per mm(2)), peaked after 48 hours (20.9 +/- 8.4 per mm(2)), and remained high at 120 hours. The MPO activity increased in the ischemic basal ganglia 12 hours after MCAO (0.111 +/- 0.023 U/g), peaked after 24 hours (0.194 +/- 0.059 U/g), and decreased after 72 hours. In the ischemic cortex, the MPO activity increased 12 hours after MCAO (0.110 +/- 0.032 U/g), peaked after 24 hours (0.210 +/- 0.067 U/g), and remained elevated at 120 hours. CONCLUSIONS: The increased expression of ICAM-1 in the ischemic brain of mouse in the early phase of MCAO followed by the over-expression of Mac-1 and the increased MPO activity suggests that focal ischemia leads to early onset of inflammation. The inflammatory response is more persistent and intensive in the ischemic cortex than in the ischemic basal ganglia.

Inhibition of MEK/ERK 1/2 pathway reduces pro-inflammatory cytokine interleukin-1 expression in focal cerebral ischemia.

It has been proposed that mitogen-activated protein kinase (MAPK) pathways may play a role in the regulation of pro-inflammatory cytokines, such as interlukine-1, during cerebral ischemia. Our previous study showed that extracellular-signal-regulated kinases 1 and 2 (ERK 1/2) were activated during focal cerebral ischemia in mice [J. Cereb. Blood Flow Metab. 20 (2000) 1320]. However, the effect of ERK 1/2 activation in focal cerebral ischemia is still unclear. In this study we reported that in vivo phospho-ERK 1/2 expression increased following 30 min of middle cerebral artery occlusion (MCAO) in the mouse brain in both the ischemic core and perifocal regions. Western blot analysis and immunohistochemistry demonstrated that pro-treatment with 1,4-diamino-2,3-dicyano-1,4-bis butadiene (U0126) [J. Biol. Chem. 273 (1998) 18623] could significantly inhibit mouse brain phospho-MEK 1/2 and phospho-ERK 1/2 expression after 1-2 h of MCAO (p<0.05). Compared to the control group of mice, brain infarct volume was significantly decreased after 24 h of MCAO in the U0126-treated mice (27+/-6 vs. 46+/-9 mm(2), p<0.05). Inhibition of the MEK/ERK 1/2 pathway also prevented downstream kinase Elk-1 phosphorylation, and further reduced cytokine IL-1beta mRNA, but not TNFalpha, IL-1alpha, or chemokine MIP-1alpha mRNA expression. Our data demonstrates that in vivo the close linking of MEK 1/2, ERK 1/2, Elk-1, and IL-1 mRNA expression in the cerebral ischemia animals suggests that ERK 1/2 pathway activation is important in pro-inflammatory cytokine IL-1beta signaling, which induces an inflammatory response and exacerbates ischemic brain injury. Inhibiting the ERK 1/2 pathway may therefore provide a novel approach for the reduction of ischemia-induced IL-1beta overexpression.

U0126 prevents ERK pathway phosphorylation and interleukin-1beta mRNA production after cerebral ischemia.

OBJECTIVE: To study the role of extracellular signal-regulated kinase (ERK) in cerebral ischemia and the mechanism of protective effects of U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio] butadiene) on ischemic brain. METHODS: Mice underwent left middle cerebral artery occlusion (MCAO) by introducing a suture in the lumen. U0126 was injected intravenously through the internal jugular vein. The immuno-activity of phosphorylated ERK1/2 (pERK1/2), phosphorylated mitogen activated protein kinase kinase (pMEK), and phosphorylated Elk-1 (pElk-1) was assessed by Western blot analysis and immunohistochemistry. Interleukin (IL)-1beta mRNA level was measured by ribonuclease protection assay. RESULTS: Phosphorylated ERK1/2 in 2 hours MCAO mice was down-regulated after intravenous injection of U0126. The inhibition was dose dependent and treatment time related. pMEK and pElk-1 were also reduced in a similar fashion after U0126 treatment. IL-1beta mRNA increased after 1 and 2 hours of MCAO. After injection of U0126, it was down-regulated during 1 to 4 hours after MCAO. CONCLUSION: Intravenous administration of the MEK inhibitor U0126 inhibits pMEK, pERK1/2, and pElk-1 up-regulation induced by cerebral ischemia. The protective effect of U0126 against ischemic injury is probably resulted from the reduction of IL-1beta mRNA via the inhibition of ERK pathway.

Effects of extracellular signal-regulated kinase (ERK) on focal cerebral ischemia.

OBJECTIVE: To determine the role of extracellular signal-regulated kinase (ERK)1/2 during focal cerebral ischemia. METHODS: Left middle cerebral artery occlusion (MCAO) was undergone after the introduction of a nylon suture to the left internal carotid artery in 70 male adult CD-1 mice. ERK 1/2 phosphorylation was detected using Western blot analysis, and the morphological feature was determined by immunohistochemistry. An ERK pathway inhibitor, 1,4-diamino-2,3-dicyano-1,4-bis[2-amino-phenylthio] butadiene (U0126), was administered intravenously 20 minutes before MCAO, and the neurological deficit levels and the infarct volumes were measured 24 hours after MCAO. RESULTS: Phosphorylated ERK 1/2 (pERK 1/2) activity increased after 30 minutes of MCAO and peaked at 2 hours. The immunohistochemical study displayed a large number of pERK 1/2 positive cells in the ischemic basal ganglion and surrounding cortex. Double-labeled fluorescent staining identified the pERK1/2 positive cells as neurons or astrocytes. In U0126 treated mice which had undergone 24 hours of MCAO, the neurological deficit levels and the infarct volumes were 44.6% and 45.8% respectively, less than those of the control mice. CONCLUSIONS: ERK plays an important role in focal cerebral ischemia and inhibition of the ERK pathway can help protect against ischemic brain injury, which may provide a therapeutic approach for cerebral ischemia.