OBJECTIVES: The neurotoxicity of carbon monoxide (CO) to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning (DEACMP). Our previous study found that retinoic acid (RA) can suppress the neurotoxic effects of CO. This study further explores, in vivo and in vitro, the molecular mechanisms by which RA alleviates CO-induced central nervous system damage. METHODS: A cytotoxic model was established using the mouse hippocampal neuronal cell line HT22 and primary oligodendrocytes exposed to CO, and a DEACMP animal model was established in adult Kunming mice. Cell viability and apoptosis of hippocampal neurons and oligodendrocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Annexin V/propidium iodide (PI) double staining. The transcriptional and protein expression of each gene was detected using real-time fluorescence quantitative PCR (RT-qPCR) and Western blotting. Long noncoding RNA (lncRNA) SNHG15 and LINGO-1 were knocked down or overexpressed to observe changes in neurons and oligodendrocytes. In DEACMP mice, SNHG15 or LINGO-1 were knocked down to assess changes in central nervous tissue and downstream protein expression. RESULTS: RA at 10 and 20 μmol/L significantly reversed CO-induced apoptosis of hippocampal neurons and oligodendrocytes, downregulation of SNHG15 and LINGO-1, and upregulation of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) (all P<0.05). Overexpression of SNHG15 or LINGO-1 weakened the protective effect of RA against CO-induced cytotoxicity (all P<0.05). Knockdown of SNHG15 or LINGO-1 alleviated CO-induced apoptosis of hippocampal neurons and oligodendrocytes and upregulated BDNF and TrkB expression levels (all P<0.05). Experiments in DEACMP model mice showed that knockdown of SNHG15 or LINGO-1 mitigated central nervous system injury in DEACMP (all P<0.05). CONCLUSIONS RA alleviates CO-induced apoptosis of hippocampal neurons and oligodendrocytes, thereby reducing central nervous system injury and exerting neuroprotective effects. LncRNA SNHG15 and LINGO-1 are key molecules mediating RA-induced inhibition of neuronal apoptosis and are associated with the BDNF/TrkB pathway. These findings provide a theoretical framework for optimizing the clinical treatment of DEACMP and lay an experimental foundation for elucidating its molecular mechanisms.
Animals ; RNA, Long Noncoding/physiology* ; Brain-Derived Neurotrophic Factor/genetics* ; Carbon Monoxide Poisoning/complications* ; Mice ; Tretinoin/pharmacology* ; Nerve Tissue Proteins/metabolism* ; Membrane Proteins/metabolism* ; Apoptosis/drug effects* ; Hippocampus/cytology* ; Receptor, trkB/metabolism* ; Neurons/drug effects* ; Male ; Brain Diseases/etiology* ; Oligodendroglia/drug effects* ; Signal Transduction ; Cell Line

OBJECTIVES: To explore whether the antioxidant axis Nrf2/HO-1 is involved in the regulation of hippocampus injury induced by cypermethrin and its underlying mechanism. METHODS: Ten-week-old C57BL/6 mice were randomly divided into control group and cypermethrin exposure groups with low, medium, and high exposure levels. After 21 days of oral gavage of corn oil (control) or cypermethrin, the levels of MDA, T-SOD, GSH-Px and CAT in the hippocampus of the mice were examined to evaluate the oxidative stress levels. HE staining was used to observe morphological changes of the hippocampal neurons. Western blotting, immunofluorescence staining and RT-qPCR were employed to detect the protein expressions and mRNA expression of Nrf2 and HO-1 and HO-1. RESULTS: Subacute oral exposure to cypermethrin significantly increased MDA level, decreased the activities of antioxidant enzymes T-SOD, GSH-Px and CAT, and induced neuronal damage in the CA1 and CA3 regions in the hippocampus of C57BL/6 mice. Cypermethrin exposure also caused Nrf2 protein translocation from the cytoplasm to the nucleus, accompanied by upregulated expression levels of the key antioxidant factor Nrf2 and its downstream target kinase HO-1. CONCLUSIONS Cypermethrin exposure dose-dependently causes oxidative damage in the hippocampus of C57BL/6 mice, which is regulated by the Nrf2/HO-1 antioxidant pathway.
Animals ; Pyrethrins/toxicity* ; NF-E2-Related Factor 2/metabolism* ; Hippocampus/cytology* ; Mice, Inbred C57BL ; Mice ; Oxidative Stress/drug effects* ; Neurons/pathology* ; Heme Oxygenase-1/metabolism* ; Signal Transduction ; Membrane Proteins

OBJECTIVES: To explore the effects of acupuncture combined with rehabilitation training for promoting transdifferentiation of astrocytes into neurons in mice after cerebral ischemia. METHODS: Male C57/BL6J mice were subjected to intracerebral microinjection of an adeno-associated virus carrying the GFAP promoter for NeuroD1 and Ngn2 overexpression in the astrocytes, followed 3 or 12 days later by electrocoagulation of the distal middle cerebral artery. After modeling, the mice were randomly divided into model group without interventions and intervention group treated with electroacupuncture at the acupoints Baihui (GV20), left Hegu (LI4), Neiguan (PC6), Zusanli (ST36), and Yanglingquan (GB34) 24 h after surgery. The mice in the intervention group were housed individually in cages with running wheels, and their activity was recorded every 24 h. Neurological function scores of the mice were assessed on the 1st, 14th, and 21st days after modeling. Transdifferentiation of astrocytes in the target brain regions was observed using double immunofluorescence staining. RESULTS: Compared with those in the model group, the mice receiving eletroacupuncture and rehabilitation training showed significant improvement of neurological deficits at 14 and 21 days after modeling. The GFAP promoter of the AAV2/5 vector specifically labeled the local astrocytes, and compared with that that in the model group, the number of AAV-positive cells colabeled with the neuronal marker DCX significantly increased after 14 days of electroacupuncture and rehabilitation intervention, and the number of AAV-positive cells colabeled with the neuronal marker NeuN significantly increased after 21 days of intervention. CONCLUSIONS In mice with cerebral ischemia, electroacupuncture and rehabilitation training can promote transdifferentiation of astrocytes into neurons in the ischemic brain region, and the efficiency of transdifferentiation is positively correlated with the improvement of motor function.
Animals ; Electroacupuncture ; Astrocytes/cytology* ; Cell Transdifferentiation ; Male ; Mice, Inbred C57BL ; Brain Ischemia/physiopathology* ; Mice ; Neurons/cytology* ; Doublecortin Protein

The thalamic reticular nucleus (TRN) plays a crucial role in regulating sensory encoding, even at the earliest stages of visual processing, as evidenced by numerous studies. Orientation selectivity, a vital neural response, is essential for detecting objects through edge perception. Here, we demonstrate that somatostatin (SOM)-expressing and parvalbumin (PV)-expressing neurons in the TRN project to the dorsal lateral geniculate nucleus and modulate orientation selectivity and the capacity for visual information processing in the primary visual cortex (V1). These findings show that SOM-positive and PV-positive neurons in the TRN are powerful modulators of visual information encoding in V1, revealing a novel role for this thalamic nucleus in influencing visual processing.
Animals ; Somatostatin/metabolism* ; Parvalbumins/metabolism* ; Neurons/physiology* ; Thalamic Nuclei/physiology* ; Visual Pathways/physiology* ; Mice ; Mice, Inbred C57BL ; Visual Perception/physiology* ; Male ; Mice, Transgenic ; Visual Cortex/physiology* ; Primary Visual Cortex/cytology*

Humans and animals have a fundamental ability to use experiences and environmental information to organize behavior. It often happens that humans and animals make decisions and prepare actions under uncertain situations. Uncertainty would significantly affect the state of animals' minds, but may not be reflected in behavior. How to "read animals' mind state" under different situations is a challenge. Here, we report that neuronal activity in the medial prefrontal cortex (mPFC) of rats can reflect the environmental uncertainty when the task situation changes from certain to uncertain. Rats were trained to perform behavioral tasks under certain and uncertain situations. Under certain situations, rats were required to simply repeat two nose-poking actions that each triggered short auditory tone feedback (single-task situation). Whereas under the uncertain situation, the feedback could randomly be either the previous tone or a short musical rhythm. No additional action was required upon the music feedback, and the same secondary nose-poking action was required upon the tone feedback (dual-task situation); therefore, the coming task was uncertain before action initiation. We recorded single-unit activity from the mPFC when the rats were performing the tasks. We found that in the dual task, when uncertainty was introduced, many mPFC neurons were actively engaged in dealing with the uncertainty before the task initiation, suggesting that the rats could be aware of the task situation change and encode the information in the mPFC before the action of task initiation.
Animals ; Prefrontal Cortex/cytology* ; Uncertainty ; Neurons/physiology* ; Male ; Rats ; Rats, Long-Evans ; Action Potentials/physiology* ; Acoustic Stimulation

OBJECTIVE: To explore the effects and mechanisms of the C-X-C motif chemokine ligand 12/C-X-C motif chemokine receptor 4 (CXCL12/CXCR4) signaling axis on apoptosis and autophagy in SH-SY5Y neuronal cells subjected to oxygen-glucose deprivation/reperfusion (OGD/R) model in vitro. METHODS: SH-SY5Y cells were divided into the following groups: OGD/R group and non-OGD/R group, with the OGD/R group subjected to OGD/R modeling and the non-OGD/R group receiving no treatment. Cells were also divided into CXCL12⁺ and CXCL12^- groups; the CXCL12⁺ group received 0.1 mg/L exogenous recombinant CXCL12 (rhCXCL12) at reoxygenation, while the CXCL12^- group did not. Another set of cells was divided into CXCL12+AMD3100 and CXCL12 groups; the CXCL12+AMD3100 group was pretreated with 2.5 mg/L AMD3100, a CXCR4 inhibitor, for 2 hours before OGD/R and received both 2.5 mg/L AMD3100 and 0.1 mg/L rhCXCL12 at reoxygenation, whereas the CXCL12 group received rhCXCL12 only. Additionally, cells were divided into small interfering RNA CXCR4 (siCXCR4) and small interfering RNA negative control (siNC) groups; the siCXCR4 group underwent CXCR4 knockdown before OGD/R modeling and received 0.1 mg/L rhCXCL12 at reoxygenation, while the siNC group, transfected with a negative control, received the same treatment. Protein expression of autophagy-related 16 (ATG16), microtubule-associated protein 1 light chain 3 (LC3), aquaporin-3 (AQP3), and CXCR4 was detected by Western blotting. Apoptosis rate and CXCR4 expression were measured by flow cytometry. RESULTS: Compared with the non-OGD/R group, the OGD/R group showed a significantly increased apoptosis rate and markedly decreased protein expression levels of ATG16, LC3, AQP3, and CXCR4 (all P < 0.05). CXCR4 fluorescent expression was also significantly reduced, suggesting that OGD/R simultaneously affects neuronal apoptosis and autophagy while inhibiting CXCR4 and AQP3 expression in SH-SY5Y cells. Compared with the CXCL12^- group, the CXCL12⁺ group exhibited no significant change in apoptosis rate but demonstrated significantly increased protein expression of ATG16, LC3, and AQP3 (ATG16/GAPDH: 1.21±0.10 vs. 1.00±0.00; LC3/β-actin: 1.22±0.10 vs. 1.00±0.00; AQP3/β-actin: 1.26±0.04 vs. 1.00±0.00; all P < 0.05). CXCR4 expression was also significantly enhanced (fluorescence intensity: 1.19±0.05 vs. 1.00±0.00, P < 0.05), indicating that CXCL12 may promote autophagy in OGD/R-injured SH-SY5Y cells via the CXCR4/AQP3 pathway. Compared with the CXCL12 group, the CXCL12+AMD3100 group showed no significant difference in apoptosis rate but significantly lower protein levels of ATG16 and LC3 (ATG16/GAPDH: 0.75±0.08 vs. 1.00±0.00; LC3/GAPDH: 0.86±0.07 vs. 1.00±0.00; both P < 0.05), suggesting that CXCL12 induces autophagy in OGD/R SH-SY5Y cells through CXCR4. Compared with the siNC group, the siCXCR4 group showed no significant change in apoptosis rate but significantly reduced protein expression of ATG16, LC3, AQP3, and CXCR4 (ATG16/GAPDH: 0.76±0.06 vs. 1.00±0.00; LC3/GAPDH: 0.79±0.11 vs. 1.00±0.00; AQP3/GAPDH: 0.81±0.05 vs. 1.00±0.00; CXCR4/GAPDH: 0.86±0.04 vs. 1.00±0.00; all P < 0.05), indicating that CXCR4 knockdown suppresses OGD/R-induced autophagy in SH-SY5Y cells likely via AQP3. CONCLUSIONS The CXCL12/CXCR4 signaling axis can regulate OGD/R-induced autophagy in SH-SY5Y cells through AQP3 without affecting apoptosis, indicating a role for this pathway in neuronal autophagy during cerebral ischemia/reperfusion injury.
Humans ; Receptors, CXCR4/metabolism* ; Chemokine CXCL12/metabolism* ; Autophagy ; Glucose/metabolism* ; Apoptosis ; Neurons/cytology* ; Oxygen/metabolism* ; Signal Transduction ; Cell Line, Tumor ; Cell Hypoxia ; Benzylamines ; Cyclams

Buyang Huanwu Decoction(BYHWD), as one of the classic formulas in traditional Chinese medicine(TCM) for the treatment of cerebral ischemic stroke(CIS), has demonstrated definite effects in clinical practice. However, the material basis and mechanism of treatment have not been systematically elucidated. This study employed network pharmacology and molecular docking to analyze the potential targets and mechanisms of blood-and brain-penetrating active components of BYHWD in reducing cell apoptosis in CIS. Cell experiments were then carried out to validate the prediction results. In the experiments, five active components including hydroxysafflor yellow A( HSYA), tetramethylpyrazine( TMP), astragaloside Ⅳ( AS-Ⅳ), amygdalin( AMY), and paeoniflorin(PF) were selected to explore the pharmacological effects of BYHWD. HT22 cells were treated with BYHWD, and the cell counting kit-8(CCK-8) method was employed to examine the toxic and side effects of BYHWD. A cell model of oxygen-glucose deprivation/reoxygenation( OGD/R) was constructed, with apoptosis and pyroptosis as the main screening indicators. The levels of lactate dehydrogenase(LDH) and glutathione(GSH) were measured to assess the cell membrane integrity. Flow cytometry was employed to detect apoptosis, and the activities of caspase-3 and caspase-1 were measured to clarify the status of apoptosis and pyroptosis. ELISA was employed to determine the levels of interleukin(IL)-1β and IL-18 to confirm pyroptosis. HSYA and AMY were identified in this study as the active components regulating apoptosis and pyroptosis. TUNEL was employed to detect the apoptosis rate, and Western blot was employed to determine the expression levels of apoptosis-related proteins B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), and caspase-3, which confirmed that the anti-apoptotic effect of the combined component group was superior to that of the single component groups. The molecular docking results revealed strong binding affinity of HSYA and AMY with SDF-1α and CXCR4.AMD3100, a selective antagonist of CXCR4, was then used for intervention. The results of Western blot showed alterations in the expression levels of apoptosis-associated proteins, SDF-1α, and CXCR4. In conclusion, HSYA and AMY influence cellular apoptosis by modulating the SDF-1α/CXCR4 signaling cascade.
Drugs, Chinese Herbal/chemistry* ; Apoptosis/drug effects* ; Animals ; Neurons/cytology* ; Mice ; Molecular Docking Simulation ; Cell Line ; Glucose/metabolism* ; Humans ; Neuroprotective Agents/pharmacology*

This study investigated the effects of Rehmanniae Radix Praeparata on striatal neuronal apoptosis in rats with attention deficit hyperactivity disorder(ADHD) based on the B-cell lymphoma-2(Bcl-2)/Bcl-2-associated X protein(Bax)/caspase-3 signaling pathway. Twenty-four 3-week-old male spontaneously hypertensive rats(SHR) were randomly divided into a model group, a methylphenidate group(2 mg·kg~(-1)·d~(-1)), and a Rehmanniae Radix Praeparata group(2.4 mg·kg~(-1)·d~(-1)). Age-matched male Wistar Kyoto(WKY) rats were used as the normal control group, with 8 rats in each group. The rats were administered by gavage for 28 days. Body weight and food intake were recorded for each group. The open field test and elevated plus maze test were used to assess hyperactivity and impulsive behaviors. Nissl staining was used to detect changes in striatal neurons and Nissl bodies. Terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) fluorescence staining was used to detect striatal cell apoptosis. Western blot was employed to detect the expression levels of Bcl-2, Bax, and caspase-3 proteins in the striatum. The results showed that compared with the model group, Rehmanniae Radix Praeparata significantly reduced the total movement distance, average movement speed, and central area residence time in the open field test, and significantly reduced the ratio of open arm entries, open arm stay time, and head dipping in the elevated plus maze test. Furthermore, it increased the number of Nissl bodies in striatal neurons, significantly downregulated the apoptosis index, significantly increased Bcl-2 protein expression and the Bcl-2/Bax ratio, and reduced Bax and caspase-3 protein expression. In conclusion, Rehmanniae Radix Praeparata can reduce hyperactivity and impulsive behaviors in ADHD rats. Its mechanism may be related to the regulation of the Bcl-2/Bax/caspase-3 signaling pathway in the striatum, enhancing the anti-apoptotic capacity of striatal neurons.
Animals ; Male ; Apoptosis/drug effects* ; Rats ; Drugs, Chinese Herbal/administration & dosage* ; Caspase 3/genetics* ; Proto-Oncogene Proteins c-bcl-2/genetics* ; bcl-2-Associated X Protein/genetics* ; Rehmannia/chemistry* ; Attention Deficit Disorder with Hyperactivity/physiopathology* ; Signal Transduction/drug effects* ; Neurons/cytology* ; Rats, Inbred SHR ; Rats, Inbred WKY ; Humans ; Corpus Striatum/cytology* ; Plant Extracts

Repeated transcranial magnetic stimulation (rTMS) is one of the commonly used brain stimulation techniques. In order to investigate the effects of rTMS on the excitability of different types of neurons, this study is conducted to investigate the effects of rTMS on the cognitive function of mice and the excitability of hippocampal glutaminergic neurons and gamma-aminobutyric neurons from the perspective of electrophysiology. In this study, mice were randomly divided into glutaminergic control group, glutaminergic magnetic stimulation group, gamma-aminobutyric acid energy control group, and gamma-aminobutyric acid magnetic stimulation group. The four groups of mice were injected with adeno-associated virus to label two types of neurons and were implanted optical fiber. The stimulation groups received 14 days of stimulation and the control groups received 14 days of pseudo-stimulation. The fluorescence intensity of calcium ions in mice was recorded by optical fiber system. Behavioral experiments were conducted to explore the changes of cognitive function in mice. The patch-clamp system was used to detect the changes of neuronal action potential characteristics. The results showed that rTMS significantly improved the cognitive function of mice, increased the amplitude of calcium fluorescence of glutamergic neurons and gamma-aminobutyric neurons in the hippocampus, and enhanced the action potential related indexes of glutamergic neurons and gamma-aminobutyric neurons. The results suggest that rTMS can improve the cognitive ability of mice by enhancing the excitability of hippocampal glutaminergic neurons and gamma-aminobutyric neurons.
Animals ; Mice ; Hippocampus/cytology* ; Transcranial Magnetic Stimulation ; Neurons/physiology* ; Male ; Cognition/physiology* ; gamma-Aminobutyric Acid/metabolism* ; Action Potentials/physiology*

OBJECTIVE: To review the research progress on silk fibroin (SF)-nerve guidance conduits (NGCs) for peripheral nerve injury (PNI) repair. METHODS: To review the recent literature on PNI and SF-NGCs, expound the concepts and treatment strategies of PNI, and summarize the construction of SF-NGCs and its application in PNI repair. RESULTS: Autologous nerve transplantation remains the "gold standard" for treating severe PNI. However, it's clinical applications are constrained by the limitations of limited donors and donor area damage. Natural SF exhibits good biocompatibility, low immunogenicity, and excellent physicochemical properties, making it an ideal candidate for the construction of NGCs. SF-NGCs constructed using different technologies have been found to have better biocompatibility and bioactivity. Their configurations can facilitate nerve regeneration by enhancing regenerative guidance and axonal extension. Besides, the adhesion, proliferation and differentiation of neurons and Schwann cells related to PNI repair can be effectively promote by NGCs. This accelerates the speed of nerve regeneration and improves the efficiency of repair. In addition, SF-NGCs can be used as regenerative scaffolds to provide biological templates for nerve repair. CONCLUSION The biodegradable natural SF has been extensively studied and demonstrated promising application prospects in the field of NGCs. It might be an effective and viable alternative to the "gold standard" for PNI treatment.
Fibroins/chemistry* ; Peripheral Nerve Injuries/therapy* ; Nerve Regeneration ; Tissue Scaffolds/chemistry* ; Humans ; Guided Tissue Regeneration/methods* ; Biocompatible Materials ; Animals ; Tissue Engineering/methods* ; Schwann Cells/cytology* ; Peripheral Nerves ; Neurons/cytology*