Metabolomics-Based Effects of a Natural Product on Remyelination After Cerebral Ischemia Injury Via GABABR-pCREB-BDNF Pathway.

BACKGROUND: Yi-Qi-Tong-Luo Granules (YQTLs) is a natural compound of Traditional Chinese Medicine authorized by China Food and Drug Administration (CFDA). These granules are employed in the convalescent stage of cerebral infarction and render notable clinical efficacy. This study aims to uncover the underlying mechanisms of YQTLs on remyelination after cerebral ischemia injury. MATERIALS AND METHODS: We established cerebral ischemia model in rats using microsphere-induced multiple cerebral infarction (MCI). We evaluated the pharmacological effects of YQTLs on MCI rats, through Morri's water maze test, open field test, hematoxylin and eosin staining, and glycine silver immersion. We employed liquid chromatography mass spectrometry metabolomics to identify differential metabolites. Enzyme-linked immunosorbent assay was utilized to measure the release of neurotrophins, while immunofluorescence staining was used to assess oligodendrocyte precursor cells differences and myelin regeneration. We used Western blotting to validate the protein expression of remyelination-associated signaling pathways. RESULTS: YQTLs significantly improves cognitive function following cerebral ischemia injury. Pathological tissue staining revealed that YQTLs administration inhibits neuronal denaturation and neurofibrillary tangles. We identified 141 differential metabolites among the sham, MCI, and YQTLs-treated MCI groups. Among these metabolites, neurotransmitters were identified, and notably, gamma-aminobutyric acid (GABA) showed marked improvement in the YQTLs group. The induction of neurotrophins, such as brain-derived neurotrophic factor (BDNF) and PDGFAA, upregulation of olig2 and MBP expression, and promotion of remyelination were evident in YQTLs-treated MCI groups. Gamma-aminobutyric acid B receptors (GABABR), pERK/extracellular regulated MAP kinase, pAKT/protein kinase B, and pCREB/cAMP response element-binding were upregulated following YQTLs treatment. CONCLUSION: YQTLs enhance the binding of GABA to GABABR, thereby activating the pCREB/BDNF signaling pathway, which in turn increases the expression of downstream myelin-associated proteins and promotes remyelination and cognitive function.

Seizing the fate of lymph nodes in immunotherapy: To preserve or not?

Lymph node dissection has been a long-standing diagnostic and therapeutic strategy for metastatic cancers. However, questions over myriad related complications and survival outcomes are continuously debated. Immunotherapy, particularly neoadjuvant immunotherapy, has revolutionized the conventional paradigm of cancer treatment, yet has benefited only a fraction of patients. Emerging evidence has unveiled the role of lymph nodes as pivotal responders to immunotherapy, whose absence may contribute to drastic impairment in treatment efficacy, again posing challenges over excessive lymph node dissection. Hence, centering around this theme, we concentrate on the mechanisms of immune activation in lymph nodes and provide an overview of minimally invasive lymph node metastasis diagnosis, current best practices for activating lymph nodes, and the prognostic outcomes of omitting lymph node dissection. In particular, we discuss the potential for future comprehensive cancer treatment with effective activation of immunotherapy driven by lymph node preservation and highlight the challenges ahead to achieve this goal.

Panax notoginseng Saponins Stimulates Neurogenesis and Neurological Restoration After Microsphere-Induced Cerebral Embolism in Rats Partially Via mTOR Signaling.

P. Notoginseng Saponins (PNS), the main active component of herbal medicine Panax notoginseng, has been widely used to treat cerebrovascular diseases. It has been acknowledged that PNS exerted protection on nerve injuries induced by ischemic stroke, however, the long-term impacts of PNS on the restoration of neurological defects and neuroregeneration after stroke have not been thoroughly studied and the underlying molecular mechanism of stimulating neurogenesis is difficult to precisely clarify, much more in-depth researches are badly needed. In the present study, cerebral ischemia injury was induced by microsphere embolism (ME) in rats. After 14 days, PNS administration relieved cerebral ischemia injury as evidenced by alleviating neurological deficits and reducing hippocampal pathological damage. What's more, PNS stimulated hippocampal neurogenesis by promoting cell proliferation, migration and differentiation activity and modulated synaptic plasticity. Increased number of BrdU/Nestin, BrdU/DCX and NeuroD1-positive cells and upregulated synapse-related GAP43, SYP, and PSD95 expression were observed in the hippocampus. We hypothesized that upregulation of brain-derived neurotrophic factor (BDNF) expression and activation of Akt/mTOR/p70S6K signaling after ME could partially underlie the neuroprotective effects of PNS against cerebral ischemia injury. Our findings offer some new viewpoints into the beneficial roles of PNS against ischemic stroke.

Histochemistry of microinfarcts in the mouse brain after injection of fluorescent microspheres into the common carotid artery.

The mouse model of multiple cerebral infarctions, established by injecting fluorescent microspheres into the common carotid artery, is a recent development in animal models of cerebral ischemia. To investigate its effectiveness, mouse models of cerebral infarction were created by injecting fluorescent microspheres, 45-53 µm in diameter, into the common carotid artery. Six hours after modeling, fluorescent microspheres were observed directly through a fluorescence stereomicroscope, both on the brain surface and in brain sections. Changes in blood vessels, neurons and glial cells associated with microinfarcts were examined using fluorescence histochemistry and immunohistochemistry. The microspheres were distributed mainly in the cerebral cortex, striatum and hippocampus ipsilateral to the side of injection. Microinfarcts were found in the brain regions where the fluorescent microspheres were present. Here the lodged microspheres induced vascular and neuronal injury and the activation of astroglia and microglia. These histopathological changes indicate that this animal model of multiple cerebral infarctions effectively simulates the changes of various cell types observed in multifocal microinfarcts. This model is an effective, additional tool to study the pathogenesis of ischemic stroke and could be used to evaluate therapeutic interventions. This study was approved by the Animal Ethics Committee of the Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences (approval No. D2021-03-16-1) on March 16, 2021.

Chinese Herbal Preparation SaiLuoTong Alleviates Brain Ischemia via Nrf2 Antioxidation Pathway-Dependent Cerebral Microvascular Protection.

Stroke is one of the most devastating diseases worldwide. The Chinese herbal preparation SaiLuoTong (SLT) capsule showed outstanding therapeutic effects on stroke and its sequelae. The aim of this study was to further elucidate its therapeutic mechanism. We duplicated a permanent cerebral ischemia model in rats by MCAO and used SLT (33 and 16.5 mg/kg) to intervene. The results showed SLT dose dependently decreased infarction volumes, relieved neuron degeneration and loss, and ameliorated neurological functions, and the dose of 33 mg/kg had statistical significance (compared with the model group, p < 0.05); SLT of 33 mg/kg also significantly inhibited the elevation in brain water content and the loss in claudin-1 and occludin expressions; additionally, it significantly increased nucleus translocation of Nrf2, elevated the expression of HO-1, and raised the activity of SOD and content of GSH (compared with the model group, p < 0.05 or 0.01). These results testified SLT's anti-brain ischemia effect and hint this effect may be related to the protection of brain microvascular endothelial cells (BMECs) that is dependent on the Nrf2 pathway. To further testify, we cultured hCMEC/D3 cells, duplicated OGD/R model to simulate ischemia, and used SLT (3.125, 6.25, and 12.5 mg/L) to treat. SLT dose dependently and significantly inhibited the drop in cell viabilities, and activated the Nrf2 pathway by facilitating Nrf2 nucleus translocation, and increasing HO-1 expression, SOD activity, and GSH content (compared with the model group, p < 0.05 or 0.01); last, the anti-OGD/R effects of SLT, including raising cell viabilities, inhibiting the elevation in dextran permeability, and preserving expressions of claudin-1 and occludin, were all abolished by Nrf2 siRNA interference. The in vitro experiment undoubtedly confirmed the direct protective effect of SLT on BMECs and the obligatory role of the Nrf2 pathway in it. Collectively, data of this study suggest that SLT's therapeutic effect on brain ischemia is related to its Nrf2-dependent BMECs protection.

[Characterization and pathophysiological changes of cerebral infarction rat model with qi-deficiency and blood-stasis Syndrome].

This study aimed to observe the general state and changes in pathophysiological indexes of multiple cerebral infarction rat model with Qi-deficienty and Blood-stasis syndrome. Rats were randomly divided into 4 groups(with 30 in each group): the normal group, the sham group, the model group and the Yiqi Huoxue recipe group. Rats in the model group and Yiqi Huoxue group were provided with interruptable sleep deprivation for 7 days before the multiple cerebral infarction operation, and followed by another 4 weeks of sleep deprivation; rats in the Yiqi Huoxue group were intragastrically administrated with drug at a dose of 26 g·kg⁻¹, once a day for 4 weeks. The general state was observed, and the pathophysiological indexes were measured at 48 h, 2 weeks and 4 weeks after administration. The results showed that rats in the normal group and the sham group represented a good general state and behaviors, with a normal morphological structure of brain tissues; rats in the model group featured yellow fur, depression, accidie, loose stools and movement disorder, with obvious brain histomorphological damage, which became aggravated with the increase of modeling time; rats in the Yiqi Huoxue group showed release in the general state and above indexes. Compared with the sham group at three time points, rats in the model group showed decrease in body weight, exhaustive swimming time and RGB value of tongue surface image, and increase in whole blood viscosity of the shear rate under 5, 60 and 150 S⁻¹, reduction in cerebral cortex Na⁺-K⁺-ATPase, Ca²âº-ATPase activity and contents of 5-HT, rise in TXB2 levels and decline in 6-keto-PGF1a in serum(P<0.05, P<0.01). Compared with the model group, rats in the Yiqi Huoxue group showed alleviations in the above indexes at 2 w and 4 w(P<0.05, P<0.01). The results showed that the characterization and pathophysiological indexes in the multiple cerebral infarction rat model with Qi-deficiency and blood-stasis syndrome were deteriorated; Yiqi Huoxue recipe could significantly alliviate the abnormal conditions, which suggested of the model was stable and reliable and the pathophysiologic evolutionary mechanism might be related to energy metabolism dysfunction, vasoactive substance abnormality and changes in neurotransmitters.

[Effect of sailuotong capsule on intervening cognitive dysfunction of multi-infarct dementia in rats].

OBJECTIVE: To study the effect of Sailuotong capsule (Sailuotong) on learning and memory functions of multi-infarct dementia (MID) rats and its mechanism. METHOD: All SD rats were divided into five groups, namely the sham operation group, the model group, the positive group, the low dosage Sailuotong-treated group and the high dosage Sailuotong-treated group. The multi-infarct dementia model was established by injecting the micro-sphere vascular occlusive agent. On the 10th day after the successful operation, the rats were administered intragastrically with distilled water, memantine hydrochloride (20 mg x kg(-1)) and Sailuotong (16.5 mg x kg(-1) and 33.0 mg x kg(-1)) once a day for 60 days respectively, in order to detect the effect of Sailuotong in different doses on the latent period and route length in Morris water maze and the activities of choline acetyltransferase (ChAT) and acetylcholinesterase (AchE) in brain tissues. RESULT: Compared with the sham operation rats, it had been observed that the latent period and route length of MID rats in Morris water maze were significantly increased (P < 0.05 or P < 0.01), and the activity of ChAT in brain tissues was significantly decreased (P < 0.05). After the intervention with Sailuotong for sixty days, the latent period and route length of MID rats in Morris water maze significantly shrank (P < 0.05 or P < 0.01). Additionally, Sailuotong decreased AchE activity, while increasing ChAT activity in brain tissues of MID rats (P < 0.05 or P < 0.01). CONCLUSION: Sailuotong capsule can improve cognitive dysfunction of MID rats to some extent. Its mechanism may be related to its different regulation of activities of ChAT and AchE in brain tissues.

[Effect of sailuotong capsule on Glu and GABA levels as well as NMDA receptor subtypes expression in recovery period of rat multiple cerebral infarction].

The rat model of multi-infarct was adopted in this study to elucidate the protective mechanism of Sailuotong capsule (Sailuotong) in recovery period of multiple cerebral infarction. The effects of Sailuotong on levels of Glu, GABA and the expression of NMDA receptor subtypes including NR1, NR2A and NR2B, were detected. The multi-infarct model rats were established by injecting embolizing microsphere via internal carotid artery, and were given Sailuotong treatment (16.5 and 33.0 mg x kg(-1)) for 60 days. The pathological changes in brain ultrastructure were observed by transmission electron microscope. The levels of Glu and GABA in brain tissue were measured with high performance liquid chromatography. The expression of NMDA receptors including NR1, NR2A and NR2B in neurons was evaluated by immunohistochemical staining. Compared with the sham rats, abnormal changes were observed in ultrastructures of neurons, neuroglia cells and synapses of model rat brains. Moreover, significant decrease of Glu and GABA, as well as the elevated expression of NR1, NR2A and NR2B were detected in brain tissues. Sailuotong (16.5 and 33.0 mg x kg(-1)) could improve ultrastructure of cerebral tissue, facilitate synthesis of Glu and GABA, and down-regulate expression of NR1, NR2A and NR2B in neurons. The results demonstrated that Sailuotong could exert neuroprotective effects to some extent in the recovery phase of multiple cerebral infarction by promoting expression of NMDA receptors and synthesis of Glu and GABA.