Rat Cerebral Cortex Research Articles

Key Proteins in Rat Cerebral Cortex: Application of Cornu aspersum Extract as a Neuroprotective Agent in Alzheimer's Type Dementia.

Alzheimer's disease (AD) is the most widespread neurodegenerative disorder. Recently, it was found that mucus extract from Cornu aspersum has beneficial effects on memory and cognitive processes in a rat scopolamine model of AD. The present study elucidated the mechanisms of action of standardized mucus snail extract (SE) enriched with a fraction above 20 kDa on Alzheimer-type dementia in rats. Using proteomic analysis on two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) on rat cortex extracts, we compared protein expression in both groups: the first group was treated intraperitoneally with scopolamine (Sco, 2 mg/kg, 11 days) and the second (Sco + SE) group was treated intraperitoneally with Sco (Sco, 2 mg/kg) and protected by SE (0.5 mL/100 g bw) applied daily orally for 11 days. Brain cortex was separated and the expressions of various proteins related to memory and cognitive functions were identified. We found that the expression of Ubiquitin carboxyl-terminal hydrolase isozyme L1, Calbindin, Vacuolar ATP synthase catalytic subunit A, Tropomyosin beta chain, 14-3-3 zeta/delta, Kinesin-1 heavy chain, and Stathmin-4 significantly differs in SE-protected rats as compared to dement animals treated only by Sco, and these brain proteins might be potential therapeutic targets for Alzheimer's-type dementia treatment.

Role of vitamin D3 in mitigating sodium arsenite-induced neurotoxicity in male rats.

Arsenic is associated with various neurological disorders, notably affecting memory and cognitive functions. The current study examined the protective effects of vitamin D3 (Vit. D3) in countering oxidative stress, neuroinflammation and apoptosis induced by sodium arsenite (SA) in the cerebral cortex of rats. Male Wistar rats were subjected to a daily oral administration of sodium arsenite (NaAsO2, SA) at a dosage of 5mg/kg, along with 500IU/kg of Vit. D3, and a combination of both substances for four weeks. The results indicated that Vit. D3 effectively mitigated the SA-induced increase in oxidative stress markers, thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO), the decrease in antioxidants (reduced glutathione; GSH, superoxide dismutase; SOD, catalase; CAT, and glutathione peroxidase; GPx), as well as the increase in pro-inflammatory markers including, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and amyloid-beta (Aβ)1-42. Furthermore, Vit. D3 reversed the alterations in the neurochemicals acetylcholinesterase (AchE), monoamine oxidase (MAO), dopamine (DA), and acetylcholine (Ach) and ameliorated the histopathological changes in the cerebral cortex. Moreover, immunohistochemical analyses revealed that Vit. D3 reduced the SA-induced overexpression of cerebral cysteine aspartate-specific protease-3 (caspase-3) and glial fibrillary acidic protein (GFAP) in the cerebral cortex of male rats. Consequently, the co-administration of Vit. D3 can protect the cerebral cortex against SA-induced neurotoxicity, primarily through its antioxidant, anti-inflammatory, anti-apoptotic, and anti-astrogliosis effects.

THE EFFECT OF SODIUM DEOXYCHOLATE AND TWЕЕN-20 ON THE ACTIVITY AND PROPERTIES OF NA+/K+-ATPase IN THE MIXED MEMBRANE FRACTION OF THE CEREBRAL CORTEX OF RATS

Interoduction. The present work extends the understanding of the activity of ouabain-sensitive (α2 and α3) and ouabain-resistant (α1) Na+/K+-ATPase isoforms in the mixed membrane fraction of rat cerebral cortex in the presence of various detergents. The aim of the study: to determine the activity of ouabain-sensitive (α2 and α3) and ouabain-resistant (α1) Na+/K+-ATPase isoforms by changing the concentration of Mg+2 ions in the incubation medium and using the detergents sodium deoxycholate and Tween-20. Material and methods. To determine Na+/K+-ATPase activity, we used the method of A. Kazennova et al. The reaction was triggered by adding ho-mogenate of cerebral cortex incubated with detergents; the samples were incubated for 30 minutes in a water bath at 370 C. The activity of ouabain-sensitive isoforms was determined by adding 200 μmol of ouabain to the incubation mixture. The activity of ouabain-sensitive isoforms was deter-mined by adding 200 μmol ouabain to the incubation mixture, and the activity of ouabain-resistant isoforms was determined as the difference between the total Na+/K+-ATPase activity and the activity of ouabain-sensitive isoforms. ATPase activity was determined by inorganic phosphate (Pi) increment as the difference between total ATPase activity, magnesium ATPase activity, in reaction with ammonium molybdate and tin chloride in the presence of ascorbic acid as a reducing agent. Results. At optimal concentrations of detergents Dox-Na (1.25 mg/mL) and Tween-20 (6.5 mg/mL), both ouabain-sensitive and ouabain-resistant Na+/K+-ATPase isoforms are characterized by normal activity dynamics from the concentration of Mg2+ ions. Consequently, the use of detergents at given concentrations does not change the ability of enzymes to conformational rearrangements during the reaction cycle. It was found that both used detergents allow to reveal a significant percentage of latent activity of ouabain-sensitive (α2 and α3) and ouabain-resistant (α1) Na+/K+-ATPase isoforms in the mixed mebran fraction of the cerebral cortex of rats. Conclusion. The study of Mg2+-dependent properties revealed a similar character of the curves of dependence of enzyme activity on the concentra-tion of Mg2+ in the incubation medium for all Na+/K+-ATPase isoforms studied

Protective effect of aspirin and gentisic acid, a plant-derived phenolic acid, on acrylamide-induced neurotoxicity by inhibiting apoptosis and autophagy.

Acrylamide (ACR) is a toxic agent for humans and animals. Gentisic acid, anaspirinmetabolite, has antioxidant activity. Therefore, the present study investigated the probable protective effects of aspirin and gentisic acid on ACR-induced neurotoxicity in PC12 cells and rats. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to assess the effects of aspirin and gentisic acid (1.25, 2.5, 5 µM) on ACR (5 mM) toxicity. Male Wistar rats were randomly divided into 13 groups: (1) Control group, (2) ACR (50 mg/kg, 11 days, i.p.), (3-5) ACR + aspirin (25, 50, 75 mg/kg, 11 days, p.o.), (6-8) ACR + gentisic acid (25, 50, 75 mg/kg, 11 days, p.o.), (9) ACR + vitamin E (200 mg/kg, every other day, i.p.), (10, 11) Aspirin (75, 100 mg/kg, 11 days, p.o.), (12, 13) Gentisic acid (75, 100 mg/kg, 11 days, p.o.). Behavioral tests were assessed on the final day of the study. In the cerebral cortex, malondialdehyde (MDA), glutathione (GSH), cleaved-caspase-3, and microtubule-associated protein 1A/1B-light chain 3 (LC3) protein levels were evaluated. When compared with the ACR group, aspirin (2.5, 5 µM) and gentisic acid (2.5 µM) significantly enhanced cell viability. In comparison to the control group, ACR induced severe motor impairment, elevated MDA, cleaved-caspase-3, LC3 II/I ratio, and decreased GSH levels in the cerebral cortex of rats. ACR-induced changes were significantly reversed by aspirin and gentisic acid (25 mg/kg). Oxidative stress, apoptosis, and autophagy play important roles in the neurotoxicity of ACR. Aspirin and gentisic acid significantly reduced ACR-induced toxicity by inhibiting the mentioned mechanisms.

The Possible Protective Effect of Taurine on Bisphenol Induced Structural Changes on the Cerebral Cortex of Rats: Histological and Immunohistochemical Study.

Bisphenol A (BPA) is a chemical compound that has been used in many industries, such as paints and dental sealants. Taurine is a semi-essential amino acid with antioxidant, anti-inflammatory, and anti-apoptotic actions. This study aimed to evaluate the possible protective effect of taurine on BPA-induced structural changes in the cerebral cortex of rats using histological and immunohistochemical methods. 35 Wistar rats (180-200 gm) were divided into control: 10 rats; Group I: 5 rats received corn oil (0.5 mL/day); Group II (Bisphenol low dose; BPAL): 5 rats received a low dose of BPA (25 mg/kg/three times/week); Group III (Bisphenol high dose; BPAH): 5 rats received a high dose of BPA (100 mg/kg/three times/week; Group IV: (BPAL + taurine): 5 rats received taurine 100 mg/kg/day and BPAL (25 mg/kg/three times/week); Group V: (BPAH + taurine): 5 rats received taurine 100 mg/kg/day and BPH (100 mg/kg/ three times/week). BPAL& BPAH groups showed significant dose-dependent histological changes of the neuropil, pyramidal, and neuroglial cells at H&E stained sections, significantly increased GFAP, caspase- 3 immunohistochemical reaction with cells positive for Ki67 with many mitotic figures. BPAL + taurine and BPAH + taurine groups showed amelioration of the previously mentioned results. Taurine ameliorated the structural changes induced by BPA in the cerebral cortex of rats.

GET73 modulates lipopolysaccharide- and ethanol-induced increase in cytokine/chemokine levels in primary cultures of microglia of rat cerebral cortex.

- Alcohol-induced pro-inflammatory activation might influence cellular and synaptic pathology, thus contributing to the behavioral phenotypes associated with alcohol use disorders. In the present study, the possible anti-inflammatory properties of N-[(4-trifluoromethyl)-benzyl]4-methoxybutyramide (GET73), a promising therapeutic agent for alcohol use disorder treatment, were evaluated in primary cultures of rat cortical microglia. - Primary cultures of cerebral cortex microglial cells were treated with 100 ng/ml lipopolysaccharide (LPS; 8h, 37°C) or 75 mM ethanol (EtOH; 4 days, 37°C) alone or in the presence of GET73 (1-30 µM). At the end of the incubation period, multiparametric quantification of cytokines/chemokines was performed by using the xMAP technology and Luminex platform. Furthermore, cultured microglial cell viability following the treatment with EtOH and GET73, alone or in combination, has been measured by a colorimetric assay (i.e. MTT assay). - GET73 (10 and 30 µM) partially or fully prevented the LPS-induced increase of IL-6, IL-1β, RANTES/CCL5 protein and MCP-1/CCL2 levels. On the contrary, GET73 failed to attenuate the TNF-α level increase induced by LPS. Furthermore, GET73 treatment (10-30 µM) significantly attenuated or prevented the EtOH-induced increase of TNF-α, IL-6, IL-1β and MCP-1/CCL2 levels. Finally, at all the concentrations tested (1-30 µM), the GET73 treatment did not alter the EtOH-induced reduction of microglial cell viability. - The current results provide the first in vitro evidence of GET73 protective properties against EtOH-induced neuroinflammation. These data add more information on the complex and multifactorial profile of action of the compound, further supporting the significance of developing GET73 as a therapeutic tool for the treatment of individuals with alcohol use disorders.

Investigation of Persistent Photoconductivity of Gallium Nitride Semiconductor and Differentiation of Primary Neural Stem Cells.

A gallium nitride (GaN) semiconductor is one of the most promising materials integrated into biomedical devices to play the roles of connecting, monitoring, and manipulating the activity of biological components, due to its excellent photoelectric properties, chemical stability, and biocompatibility. In this work, it was found that the photogenerated free charge carriers of the GaN substrate, as an exogenous stimulus, served to promote neural stem cells (NSCs) to differentiate into neurons. This was observed through the systematic investigation of the effect of the persistent photoconductivity (PPC) of GaN on the differentiation of primary NSCs from the embryonic rat cerebral cortex. NSCs were directly cultured on the GaN surface with and without ultraviolet (UV) irradiation, with a control sample consisting of tissue culture polystyrene (TCPS) in the presence of fetal bovine serum (FBS) medium. Through optical microscopy, the morphology showed a greater number of neurons with the branching structures of axons and dendrites on GaN with UV irradiation. The immunocytochemical results demonstrated that GaN with UV irradiation could promote the NSCs to differentiate into neurons. Western blot analysis showed that GaN with UV irradiation significantly upregulated the expression of two neuron-related markers, βIII-tubulin (Tuj-1) and microtubule-associated protein 2 (MAP-2), suggesting that neurite formation and the proliferation of NSCs during differentiation were enhanced by GaN with UV irradiation. Finally, the results of the Kelvin probe force microscope (KPFM) experiments showed that the NSCs cultured on GaN with UV irradiation displayed about 50 mV higher potential than those cultured on GaN without irradiation. The increase in cell membrane potential may have been due to the larger number of photogenerated free charges on the GaN surface with UV irradiation. These results could benefit topical research and the application of GaN as a biomedical material integrated into neural interface systems or other bioelectronic devices.

Study on the Effects of Acupuncture with the "Yizhi Tiaoshen" Acupoint Formula on Blood Oxygen Metabolism and Neural Function in Key Brain Regions of AD Rats.

Exploring the effects of acupuncture at the "Yizhi Tiaoshen" acupoint on blood oxygen metabolism and neurological function changes in the brain regions of AD model rats. The AD model was replicated by intraperitoneal injection of D-galactose combined with bilateral hippocampal CA1 injection of Okadaic acid (OA). Thirty rats with successfully replicated model were selected through Morris water maze experiment and randomly divided into model group, donepezil hydrochloride group, and acupuncture group, with 10 rats in each group. After treatment, fNIRs were used to detect changes in Oxy Hb, Deoxy Hb, and Total Hb in the cerebral cortex of rats in each group, in order to evaluate the neurological function changes in key brain areas. The escape latency of the donepezil hydrochloride group and the acupuncture group was shortened, the number of crossings through the original platform increased, and the duration of stay in the quadrant where the original platform was located was prolonged. Based on fNIRs detection, the main differential channels of blood oxygen metabolism in AD rats were identified as 2-2 and 8-7, corresponding to the prefrontal and parietal lobes, respectively. The concentrations of Oxy Hb and Total Hb were significantly increased in both treatment groups, while the concentration of Deoxy Hb was significantly decreased. Acupuncture with the "Yizhi Tiaoshen" acupoint formula and donepezil hydrochloride can improve the learning and memory function of AD rats, and its mechanism may be related to improving blood oxygen metabolism in the prefrontal and parietal regions and protecting neuronal function.

Effect of Suan Zao Ren (Semen Ziziphi Spinosae) Extract on the TXNIP/NLRP3 Pathway in Insomniac Rats

Abstract Objectives This study aimed to investigate the therapeutic effects of Suan Zao Ren (Semen Ziziphi Spinosae, SZS) extract on insomnia induced by p-chlorophenylalanine (PCPA) in rats and its influence on the thioredoxin-interacting protein (TXNIP)/nucleotide-binding domain Leucine-rich repeat and pyrin domain-containing receptor 3 (NLRP3) inflammasome pathway, and to preliminarily explore the mechanism by which SZS extract improves insomnia. Methods Fifty male Sprague–Dawley (SD) rats were used, with 8 rats in the blank group and 42 rats in the modeling group. The modeling group was induced by intraperitoneal injection of PCPA at a dose of 500 mg·kg−1 for six consecutive days, with daily cage exchange. After 6 days, 40 successfully modeled rats were randomly divided into five groups: the model group (equal volume of distilled water), the positive group (0.75 mg·kg−1), and low-, medium-, and high-dose SZS extract groups (1.5, 3, and 6 g·kg−1, respectively), with 8 rats in each group. Treatments were administered for seven consecutive days. Enzyme-linked immunosorbent assay was used to measure levels of 5-hydroxytryptamine (5-HT) and gamma-aminobutyric acid (GABA) in the rat cerebral cortex. The thiobarbituric acid (TBA) method was used to determine malondialdehyde (MDA) levels, and the hydroxylamine method was used to determine superoxide dismutase (SOD) levels. The 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) method was used to measure total antioxidant capacity (TAOC) in the cerebral cortex. Pathological changes in the cerebral cortex were observed, and Western blot was used to detect the protein expressions of TXNIP, NLRP3, apoptosis-associated speck-like protein containing a Caspase activation and recruitment domain (CARD), and cysteine–aspartate-specific protease 1 (Caspase-1) in the cerebral cortex. Results Compared with the blank group, the model group showed a significantly prolonged sleep latency (p < 0.001) and a significantly shortened sleep duration (p < 0.001). There were no changes in serum MDA and SOD levels. MDA levels in the cerebral cortex were significantly increased (p < 0.001), while SOD and TAOC levels were significantly decreased (p < 0.001). The 5-HT level was increased (p < 0.05), and the GABA level was significantly decreased (p < 0.001). SZS extract improved these conditions to varying degrees. Light microscopy showed no significant changes in cortical neurons but transmission electron microscopy revealed intact mitochondrial structures in the blank group, while the model group showed swollen and unclear mitochondria with reduced organelles. After 7 days of treatment, these conditions improved in the SZS extract groups. Compared with the blank group, the expressions of the four proteins in the model group were increased, and the expressions of these proteins were decreased in the SZS extract groups compared with the model group. Conclusion SZS extract may exert an antioxidant effect to treat insomnia by downregulating the expression of TXNIP/NLRP3 proteins and regulating oxidative stress levels in the cerebral cortex.

Memantine and the Kynurenine Pathway in the Brain: Selective Targeting of Kynurenic Acid in the Rat Cerebral Cortex.

Cytoprotective and neurotoxic kynurenines formed along the kynurenine pathway (KP) were identified as possible therapeutic targets in various neuropsychiatric conditions. Memantine, an adamantane derivative modulating dopamine-, noradrenaline-, serotonin-, and glutamate-mediated neurotransmission is currently considered for therapy in dementia, psychiatric disorders, migraines, or ischemia. Previous studies have revealed that memantine potently stimulates the synthesis of neuroprotective kynurenic acid (KYNA) in vitro via a protein kinase A-dependent mechanism. Here, the effects of acute and prolonged administration of memantine on brain kynurenines and the functional changes in the cerebral KP were assessed in rats using chromatographic and enzymatic methods. Five-day but not single treatment with memantine selectively activated the cortical KP towards neuroprotective KYNA. KYNA increases were accompanied by a moderate decrease in cortical tryptophan (TRP) and L-kynurenine (L-KYN) concentrations without changes in 3-hydroxykynurenine (3-HK) levels. Enzymatic studies revealed that the activity of cortical KYNA biosynthetic enzymes ex vivo was stimulated after prolonged administration of memantine. As memantine does not directly stimulate the activity of KATs' proteins, the higher activity of KATs most probably results from the increased expression of the respective genes. Noteworthy, the concentrations of KYNA, 3-HK, TRP, and L-KYN in the striatum, hippocampus, and cerebellum were not affected. Selective cortical increase in KYNA seems to represent one of the mechanisms underlying the clinical efficacy of memantine. It is tempting to hypothesize that a combination of memantine and drugs could strongly boost cortical KYNA and provide a more effective option for treating cortical pathologies at early stages. Further studies should evaluate this issue in experimental animal models and under clinical scenarios.

Albiflorin Decreases Glutamate Release from Rat Cerebral Cortex Nerve Terminals (Synaptosomes) through Depressing P/Q-Type Calcium Channels and Protein Kinase A Activity.

The purpose of this study was to investigate whether and how albiflorin, a natural monoterpene glycoside, affects the release of glutamate, one of the most important neurotransmitters involved in neurotoxicity, from cerebrocortical nerve terminals (synaptosomes) in rats. The results showed that albiflorin reduced 4-aminopyridine (4-AP)-elicited glutamate release from synaptosomes, which was abrogated in the absence of extracellular Ca2+ or in the presence of the vesicular glutamate transporter inhibitor or a P/Q-type Ca2+ channel inhibitor, indicating a mechanism of action involving Ca2+-dependent depression of vesicular exocytotic glutamate release. Albiflorin failed to alter the increase in the fluorescence intensity of 3,3-diethylthiacarbocyanine iodide (DiSC3(5)), a membrane-potential-sensitive dye. In addition, the suppression of protein kinase A (PKA) abolished the effect of albiflorin on glutamate release. Albiflorin also reduced the phosphorylation of PKA and synaptosomal-associated protein of 25 kDa (SNAP-25) and synapsin I at PKA-specific residues, which correlated with decreased available synaptic vesicles. The results of transmission electron microscopy (TEM) also observed that albiflorin reduces the release competence of synaptic vesicles evoked by 4-AP in synaptosomes. In conclusion, by studying synaptosomally released glutamate, we suggested that albiflorin reduces vesicular exocytotic glutamate release by decreasing extracellular Ca2+ entry via P/Q-type Ca2+ channels and reducing PKA-mediated synapsin I and SNAP-25 phosphorylation.

On the Feasibility of Using an Acedane-Based Fluorescent Probe to Monitor Hydrogen Sulfide in Primary Neuronal Cultures

Hydrogen sulfide (H₂S), which, under physiological conditions, exists in cells mainly in the form of anion HS–, is considered as a gaseous transmitter of inter- and intracellular signals along with nitrogen oxide and carbon monoxide. Analysis of the dynamics of H₂S content in living cells is impossible without creating sensitive and specific probes. Several acedan-based compounds have been synthesized in the group of K.H. Ahn (Singha et al., 2015. Anal. Chem. 87 (2), 1188–1195). In the presence of H₂S these probes attach to the sulfhydrilic group and form fluorescent carbocyclic compounds. The carbocyclic derivative of P3, compound csP3, was found to be optimal for fluorescence-microscopic studies in terms of spectral characteristics and response time to H₂S. In this work, we tested the suitability of csP3 to record H₂S changes in buffers mimicking the salt composition of the intracellular environment and in primary neuronal culture cells from rat cerebral cortex. It was found that reducing the polarity of the solution by adding dimethyl sulfoxide (30% by volume) caused a blue shift of the emission by ~10 nm and a twofold increase in fluorescence intensity. The csP3 fluorescence depends on the salt composition and increases in the presence of bicarbonate (NaHCO₃, 10 mM). Addition of P3 or csP3 to the neuronal culture caused a rapid increase in fluorescence, which was followed by a slow increase in fluorescence signal after 3–5 min. Glutamate (10 μM, in the presence of 10 μM glycine, 0 Mg2+) increased probe fluorescence, but only in those neurons in which delayed deregulation of calcium homeostasis did not occur. We conclude that the product of the reaction of P3 with H₂S is sensitive to a change in the salt composition of the intracellular medium and can be redistributed in cells between water and more hydrophobic environment. This means that an increase in P3 fluorescence in cells, especially after the addition of glutamate to neurons, does not necessarily indicate an increase in H₂S concentration. To confirm the feasibility of using P3 and structurally related probes as quantitative indicators of H₂S presence, additional studies of the properties of these compounds are needed.

Hematological and neurological impact studies on the exposure to naturally occurring radioactive materials

Naturally Occurring Radioactive Materials (NORM) contribute to everyone's natural background radiation dose. The technologically advanced activities of the gas and oil sectors produce considerable amounts of radioactive materials as industrial by-products or waste products. The goal of the current study is to estimate the danger of long-term liability to Technologically Enhanced Naturally Occurring Radioactive Materials (TE-NORM) on blood indices, neurotransmitters, oxidative stress markers, and β-amyloid in the cerebral cortex of rats' brains. Twenty adult male albino rats were divided into two equal groups (n = 10): control and irradiated. Irradiated rats were exposed to a total dose of 0.016 Gy of TE-NORM as a whole-body chronic exposure over a period of two months. It should be ''The results showed no significant changes in RBC count, Hb concentration, hematocrit percentage (HCT%), and Mean Corpuscular Hemoglobin Concentration (MCHC). However, there was a significant increase in the Mean Corpuscular Volume of RBCs (MCV) and a significant decrease in cell distribution width (RDW%) compared to the control. Alteration in neurotransmitters is noticeable by a significant increase in glutamic acid and significant decreases in serotonin and dopamine. Increased lipid peroxidation, decreased glutathione content, superoxide dismutase, catalase, and glutathione peroxidase activities indicating oxidative stress were accompanied by increased β-amyloid in the cerebral cortex of rats' brains. The findings of the present study showed that chronic radiation liability has some harmful effects, that may predict the risks of future health problems in occupational radiation exposure in the oil industries. Therefore, the control of exposure and application of sample dosimetry is recommended for health and safety.

Melatonin alleviates autophagy in cortical neurons of neonatal rats with hypoxic- ischemic brain damage via the PI3K/AKT pathway

To observe the effects of melatonin on autophagy in cortical neurons of neonatal rats with hypoxic-ischemic brain damage (HIBD) and to explore its mechanisms via the PI3K/AKT signaling pathway, aiming to provide a basis for the clinical application of melatonin. Seven-day-old Sprague-Dawley neonatal rats were randomly divided into a sham operation group, an HIBD group, and a melatonin group (n=9 each). The neonatal rat HIBD model was established using the classic Rice-Vannucci method. Neuronal morphology in the neonatal rat cerebral cortex was observed with hematoxylin-eosin staining and Nissl staining. Autophagy-related protein levels of microtubule-associated protein 1 light chain 3 (LC3) and Beclin-1 were detected by immunofluorescence staining and Western blot analysis. Phosphorylated phosphoinositide 3-kinase (p-PI3K) and phosphorylated protein kinase B (p-AKT) protein expression levels were measured by immunohistochemistry and Western blot. The correlation between autophagy and the PI3K pathway in the melatonin group and the HIBD group was analyzed using Pearson correlation analysis. Twenty-four hours post-modeling, neurons in the sham operation group displayed normal size and orderly arrangement. In contrast, neurons in the HIBD group showed swelling and disorderly arrangement, while those in the melatonin group had relatively normal morphology and more orderly arrangement. Nissl bodies were normal in the sham operation group but distorted in the HIBD group; however, they remained relatively intact in the melatonin group. The average fluorescence intensity of LC3 and Beclin-1 was higher in the HIBD group compared to the sham operation group, but was reduced in the melatonin group compared to the HIBD group (P<0.05). The number of p-PI3K+ and p-AKT+ cells decreased in the HIBD group compared to the sham operation group but increased in the melatonin group compared to the HIBD group (P<0.05). LC3 and Beclin-1 protein expression levels were higher, and p-PI3K and p-AKT levels were lower in the HIBD group compared to the sham operation group (P<0.05); however, in the melatonin group, LC3 and Beclin-1 levels decreased, and p-PI3K and p-AKT increased compared to the HIBD group (P<0.05). The correlation analysis results showed that the difference of the mean fluorescence intensity of LC3 and Beclin-1 protein in the injured cerebral cortex between the melatonin and HIBD groups was negatively correlated with the difference of the number of p-PI3K+ and p-AKT+ cells between the two groups (P<0.05). Melatonin can inhibit excessive autophagy in cortical neurons of neonatal rats with HIBD, thereby alleviating HIBD. This mechanism is associated with the PI3K/AKT pathway.

SIRT3 facilitates mitochondrial structural repair and functional recovery in rats after ischemic stroke by promoting OPA1 expression and activity

BackgroundOptical atrophy 1 (OPA1), a protein accountable for mitochondrial fusion, facilitates the restoration of mitochondrial structure and function following cerebral ischemia/reperfusion (I/R) injury. The OPA1-conferred mitochondrial protection involves its expression and activity, which can be improved by SIRT3 in non-cerebral ischemia. Nevertheless, it remains obscure whether SIRT3 enhances the expression and activity of OPA1 after cerebral I/R injury. MethodsMature male Sprague Dawley rats were intracranially injected with adeno-associated viral-Sirtuin-3(AAV-SIRT3) and AAV-sh_OPA1, followed by a 90-min temporary blockage of the middle cerebral artery and subsequent restoration of blood flow. Cultured cortical neurons of rats were transfected with LV-SIRT3 or LV-sh_OPA1 before a 2-h oxygen-glucose deprivation and reoxygenation. The rats and neurons were subsequently treated with a selective OPA1 activity inhibitor (MYLS22). The interaction between SIRT3 and OPA1 was assessed by molecular dynamics simulation technology and co-immunoprecipitation. The expression, function, and specific protective mechanism of SIRT3 were examined by various analyses. ResultsSIRT3 interacted with OPA1 in the rat cerebral cortex before and after cerebral I/R. After cerebral I/R damage, SIRT3 upregulation increased the OPA1 expression, which enhanced deacetylation and OPA1 activity, thus alleviating cerebral infarct volume, neuronal apoptosis, oxidative pressure, and impairment in mitochondrial energy production; SIRT3 upregulation also improved neuromotor performance, repaired mitochondrial ultrastructure and membrane composition, and promoted the mitochondrial biogenesis. These neuroprotective effects were partly reversed by OPA1 expression interference and OPA1 activity inhibitor MYLS22. ConclusionIn rats, SIRT3 enhances the expression and activity of OPA1, facilitating the repair of mitochondrial structure and functional recovery following cerebral I/R injury. These findings highlight that regulating SIRT3 may be a promising therapeutic strategy for ischemic stroke.

Ubiquitin ligase RFWD2 promotes dendritic spine and synapse formation by activating the ERK/PEA3/c-Jun pathway in rat cerebral cortical neurons

The regulation of protein degradation through the ubiquitin–proteasome system is essential for normal brain development, axon growth, synaptic growth and plasticity. The E3 ubiquitin ligase RFWD2 plays a key role in the onset and development of neurological diseases, including the pathogenesis of Alzheimer's disease (AD), but the mechanisms controlling the homeostasis of neuronal synaptic proteins are still poorly understood. Here, we showed that the expression level of RFWD2 gradually decreased with the age of the rats and was negatively correlated with the development of cerebral cortical neurons and dendrites in vivo. RFWD2 was shown to localize to presynaptic terminals and some postsynaptic sides of both excitatory synapses and inhibitory synapses via colocalization with neuronal synaptic proteins (SYN, PSD95, Vglut1 and GAD67). Overexpression of RFWD2 promoted dendrite development and dendritic spine formation and markedly decreased the expression of synaptophysin and PSD95 by reducing the expression of ETV1, ETV4, ETV5 and c-JUN in vitro. Furthermore, the whole-cell membrane slice clamp results showed that RFWD2 overexpression resulted in greater membrane capacitance in neuronal cells, inadequate cell repolarization, and a longer time course for neurons to emit action potentials with decreased excitability. RFWD2 regulates dendritic development and plasticity, dendritic spine formation and synaptic function in rat cerebral cortex neurons by activating the ERK/PEA3/c-Jun pathway via a posttranslational regulatory mechanism and can be used as an efficient treatment target for neurological diseases.

The potential neuroprotective of luteolin against acetamiprid-induced neurotoxicity in the rat cerebral cortex.

Acetamiprid is a class of neuroactive insecticides widely used to control insect pests. The current study aimed to investigate the potential neuroprotective effects of luteolin against acetamiprid-induced neurotoxicity in the rat cerebral cortex. Four equal groups of adult male rats (10 in each): control, acetamiprid (40 mg/kg for 28 days), luteolin (50 mg/kg for 28 days), and acetamiprid+luteolin cotreatment were used. Acetamiprid was shown to alter the oxidative state by increasing oxidant levels [nitric oxide (NO) and malondialdehyde (MDA)] and decreasing antioxidants [glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase-(CAT)], with increased activity of nuclear factor erythroid 2-related factor 2-(Nrf2). Likewise, acetamiprid increases the inflammatory response, as evidenced by increased interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and nuclear factor kappa B-(NF-κB). In contrast, the treatment with luteolin brought these markers back to levels close to normal, showing that it protects neurocytes from oxidative damage and the neuroinflammation effects of acetamiprid-induced inflammation. Luteolin also demonstrated a neuroprotective role via the modulation of acetylcholinesterase (AChE) activity in the cerebral cortex tissue. Histopathology showed severe neurodegenerative changes, and apoptotic cells were seen in the acetamiprid-induced cerebral cortex layer, which was evident by increased protein expression levels of Bax and caspase-3 and decreased Bcl-2 levels. Histochemistry confirmed the neuronal degeneration, as proven by the change in neurocyte colour from brown to black when stained with a silver stain. Luteolin may have a neuroprotective effect against biochemical and histopathological changes induced by acetamiprid in the rat cerebral cortex.

Differential changes in Wnt7 and Dkk1 levels in astrocytes exposed to glutamate or TNFα.

Wnt signaling plays an important role in adult brain function, and its dysregulation has been implicated in the loss of neuronal homeostasis. Despite the existence of many studies on the participation of the Wnt pathway in adult neurons, its regulation in astrocytes has been scarcely explored. Several reports point to the presence of Wnt ligands in astrocytes and their possible impact on neuronal plasticity or neuronal death. We aimed to analyze the effect of the neurotransmitter glutamate and the inflammatory cytokine TNFα on the mRNA and protein levels of the canonical Wnt agonist Wnt7a and the antagonist Dkk1 in cultured astrocytes. Primary astrocyte cultures from rat cerebral cortices were exposed to glutamate or TNFα. Wnt7a and Dkk1 expression was analyzed by RT-qPCR and its protein abundance and distribution was assessed by immunofluorescence. We found high basal expression and protein levels of Wnt7a and Dkk1 in unstimulated astrocytes and overproduction of Dkk1 mRNA induced by the two stimuli. These results reveal the astrocytic source of the canonical Wnt ligands Wnt7a and Dkk1, whose levels are differentially regulated by glutamate and TNFα. Astrocytes are a significant source of Wnt ligands, the production of which can be differentially regulated under excitatory or proinflammatory conditions, thereby impacting neuronal function.

Assessment of the Protective and Ameliorative Role of Quercetin Nanoparticles against Histopathological Changes Induced in the Cerebral Cortex of Rats by Acrolein

Assessment of the Protective and Ameliorative Role of Quercetin Nanoparticles against Histopathological Changes Induced in the Cerebral Cortex of Rats by Acrolein

Dose-dependent alteration in hepatic and cerebral glucose metabolism following exposure to polystyrene microplastic in Wistar rats

Background: Recently, microplastics (MPs) with dimensions less than 5 mm have gained more attention due to their adverse impact on the environment and living creatures. Polystyrene (PS) particle is a key element of primary microplastics, which are causing numerous health issues such as interruption of energy metabolism, oxidative stress, neurotoxicity, immunotoxicity, digestive gland disorders, reproductive disruption, and genotoxicity in marine living organisms. Method: Alteration in carbohydrate metabolism was evaluated in male Wistar rats (six weeks of age) after four weeks of oral exposure to polystyrene microplastic (PS-MP) at three different doses (0.5mg/L, 5mg/L and 50 mg/L via drinking water). Results: Polystyrene exposure caused a significant decrease in blood glucose, liver glycogen, and pyruvic acid content in liver and cerebral tissue. Free amino nitrogen content significantly altered in the liver and cerebrum in a dose-specific manner. The LDH activity was found to be decreased in the liver, whereas it increased in the cerebral cortex of rats in a dose-responsive fashion. Enzymes like glucose 6-phosphatase, GOT, GPT, and succinate dehydrogenase activities demonstrated differential effects on the liver and cerebrum of rats in terms of energy metabolism. Conclusion: It is suggested that sub-acute polystyrene exposure significantly perturbs glucose metabolism by inducing hypoglycemia associated with decreased glycolysis and increased TCA cycle enzyme function in rat liver in a dose-dependent manner. Gluconeogenesis is also affected differentially by metabolic adjustment in the studied organs.