Tetrandrine ameliorates sevoflurane-induced cognitive impairment via the suppression of inflammation and apoptosis in aged rats

Therapeutic effects of tetrandrine in inflammatory diseases: a comprehensive review

Inflammation can be triggered by any factor. The primary pathological manifestations can be summarized as the deterioration, exudation, and proliferation of local tissues, which can cause systemic damage in severe cases. Inflammatory lesions are primarily localized but may interact with body systems to cause provocative storms, parenchymal organ lesions, vascular and central nervous system necrosis, and other pathologic responses. Tetrandrine (TET) is a bisbenzylquinoline alkaloid extracted from the traditional Chinese herbal medicine Stephania tetrandra, which has been shown to have significant efficacy in inflammatory conditions such as rheumatoid arthritis, hepatitis, nephritis, etc., through NF-κB, MAPK, ERK, and STAT3 signaling pathways. TET can regulate the body's imbalanced metabolic pathways, reverse the inflammatory process, reduce other pathological damage caused by inflammation, and prevent the vicious cycle. More importantly, TET does not disrupt body's normal immune function while clearing the body's inflammatory state. Therefore, it is necessary to pay attention to its dosage and duration during treatment to avoid unexpected side effects caused by a long half-life. In summary, TET has a promising future in treating inflammatory diseases. The author reviews current therapeutic studies of TET in inflammatory conditions to provide some ideas for subsequent anti-inflammatory studies of TET.

Neuroprotective Agents with Therapeutic Potential for COVID-19

COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19 patients, both during the acute phase of the illness and in cases of long-term COVID. Moderate symptoms include ageusia, anosmia, altered mental status, and cognitive impairment, and in more severe cases can manifest as ischemic cerebrovascular disease and encephalitis. In this narrative review, we delve into the reported neurological symptoms associated with COVID-19, as well as the underlying mechanisms contributing to them. These mechanisms include direct damage to neurons, inflammation, oxidative stress, and protein misfolding. We further investigate the potential of small molecules from natural products to offer neuroprotection in models of neurodegenerative diseases. Through our analysis, we discovered that flavonoids, alkaloids, terpenoids, and other natural compounds exhibit neuroprotective effects by modulating signaling pathways known to be impacted by COVID-19. Some of these compounds also directly target SARS-CoV-2 viral replication. Therefore, molecules of natural origin show promise as potential agents to prevent or mitigate nervous system damage in COVID-19 patients. Further research and the evaluation of different stages of the disease are warranted to explore their potential benefits.

Tetrandrine alleviates atherosclerosis via inhibition of STING-TBK1 pathway and inflammation in macrophages

Atherosclerosis (AS) is a chronic inflammatory disease. Recent studies have showed that stimulator of interferon genes (STING), an important protein in innate immunity, mediates pro-inflammatory activation of macrophages in the development of AS. Tetrandrine (TET) is a natural bisbenzylisoquinoline alkaloid isolated from Stepania tetrandra and possesses anti-inflammatory activities, with unknown effects and mechanisms in AS. In this study, we explored the anti-atherosclerotic effects of TET and investigated the underlying mechanisms. Mouse primary peritoneal macrophages (MPMs) are challenged with cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) or oxidized LDL (oxLDL). We found that pretreatment with TET dose-dependently inhibited cGAMP- or oxLDL-induced STING/ TANK-binding kinase 1 (TBK1) signaling, then suppressing nuclear factor kappa-B (NF-κB) activation and pro-inflammatory factor expression in MPMs. ApoE^-/- mice were fed a high-fat diet (HFD) to develop an atherosclerotic phenotype. Administration of TET at 20 mg/kg/day significantly reduced HFD-induced atherosclerotic plaques, accompanied with decreased macrophage infiltration, inflammatory cytokine production, fibrosis, and STING/TBK1 activation in aortic plaque lesions. In summary, we demonstrate that TET inhibits STING/TBK1/NF-κB signaling pathway to reduce inflammation in oxLDL-challenged macrophages and alleviate atherosclerosis in HFD-fed ApoE^-/- mice. These findings proved that TET could be a potential therapeutic candidate for the treatment of atherosclerosis-related diseases.

Sevoflurane exposure causes neuronal apoptosis and cognitive dysfunction by inducing ER stress via activation of the inositol 1, 4, 5-trisphosphate receptor

The role of the inositol 1, 4, 5-trisphosphate receptor (IP3R) in hippocampal neuronal apoptosis and cognitive dysfunction induced by sevoflurane is currently unclear. Therefore, in this study, we investigated the role of the IP3R in endoplasmic reticulum (ER) stress and hippocampal neuronal apoptosis induced by sevoflurane in aged rats and isolated hippocampal neurons using both in vivo and in vitro experiments, including bioinformatics, functional enrichment analysis, gene set enrichment analysis, hematoxylin, and eosin staining, TUNEL assay, flow cytometry, western blot analysis and transmission electron microscopy. Furthermore, behavioral assessment was performed with the Morris water maze test. We identified 232 differentially expressed genes induced by sevoflurane exposure, including 126 upregulated genes and 106 downregulated genes. Sevoflurane exposure caused cognitive impairment and neuronal injury, and increased p-IP3R levels and ER stress. An IP3R inhibitor, 2-APB, suppressed these changes, while an IP3R agonist, FK-506, aggravated these changes. Together, these findings suggest that sevoflurane exposure causes marked cognitive dysfunction in aged rats and neuronal injury in isolated hippocampal neurons by activating the IP3R and inducing cytoplasmic calcium overload, thereby resulting in ER stress and hippocampal neuronal apoptosis.

GRAPHICAL ABSTRACT

Tetrandrine Attenuates Podocyte Injury by Inhibiting TRPC6-Mediated RhoA/ROCK1 Pathway

Tetrandrine (Tet), a compound found in a traditional Chinese medicine, presents the protective effect for kidney function. Our study is aimed at clarifying the efficacy and underlying mechanism of Tet on podocyte injury. In this study, podocyte injury was induced in rats with adriamycin (ADR), and MPC5 podocytes were constructed with TRPC6 overexpression. We found that Tet treatment reduced the levels of proteinuria, serum creatinine, and blood urea nitrogen and increased plasma albumin levels in ADR-induced rats. Tet reduced intracellular Ca²⁺ influx and apoptosis in MPC5 podocytes overexpressing TRPC6. Tet downregulated the expression of renal TRPC6, RhoA, and ROCK1 and upregulated the expression of synaptopodin; meanwhile, it reduced calcineurin activity in vivo and in vitro. In conclusion, Tet protects against podocyte by affecting TRPC6 and its downstream RhoA/ROCK1 signaling pathway.

Progress on structural modification of Tetrandrine with wide range of pharmacological activities

Tetrandrine (Tet), derived from the traditional Chinese herb Fangji, is a class of natural alkaloids with the structure of bisbenzylisoquinoline, which has a wide range of physiological activities and significant pharmacfological effects. However, studies and clinical applications have revealed a series of drawbacks such as its poor water solubility, low bioavailability, and the fact that it can be toxic to humans. The results of many researchers have confirmed that chemical structural modifications and nanocarrier delivery can address the limited application of Tet and improve its efficacy. In this paper, we summarize the anti-tumor efficacy and mechanism of action, anti-inflammatory efficacy and mechanism of action, and clinical applications of Tet, and describe the progress of Tet based on chemical structure modification and nanocarrier delivery, aiming to explore more diverse structures to improve the pharmacological activity of Tet and provide ideas to meet clinical needs.

DNA-Binding Properties of Bis-N-substituted Tetrandrine Derivatives

A series of bis-N-substituted tetrandrine derivatives carrying different aromatic substituents attached to both nitrogen atoms of the natural alkaloid were studied with double-stranded model DNAs (dsDNAs) to examine the binding properties and mechanism. Variable-temperature molecular recognition studies using UV-vis and fluorescence techniques revealed the thermodynamic parameters, ΔH, ΔS, and ΔG, showing that the tetrandrine derivatives exhibit high affinity toward dsDNA (K ≈ 10⁵-10⁷ M^-1), particularly the bis(methyl)anthraquinone (BAqT) and bis(ethyl)indole compounds (BInT). Viscometry experiments, ethidium displacement assays, and molecular modeling studies enabled elucidation of the possible binding mode, indicating that the compounds exhibit a synergic interaction mode involving intercalation of one of the N-aryl substituents and interaction of the molecular skeleton in the major groove of the dsDNA. Cytotoxicity tests of the derivatives with tumor and nontumor cell lines demonstrated low cytotoxicity of these compounds, with the exception of the bis(methyl)pyrene (BPyrT) derivative, which is significantly more cytotoxic than the remaining derivatives, with IC₅₀ values against the LS-180, A-549, and ARPE-19 cell lines that are similar to natural tetrandrine. Finally, complementary electrochemical characterization studies unveiled good electrochemical stability of the compounds.

Necrostatin-1 Against Sevoflurane-Induced Cognitive Dysfunction Involves Activation of BDNF/TrkB Pathway and Inhibition of Necroptosis in Aged Rats

Postoperative cognitive dysfunction (POCD) induced by anesthesia or surgery has become a common complication in the aged population. Sevoflurane, a clinical inhalation anesthetic, could stimulate calcium overload and necroptosis to POCD. In addition, necroptosis inhibitor necrostatin-1 (Nec-1) alleviated cognitive impairment caused by multiple causes, including postoperative cognitive impairment. However, whether Nec-1 exerts a neuroprotective effect on POCD via calcium and necroptosis remains unclear. We anesthetized Sprague-Dawley rats with sevoflurane to construct the POCD model and to explore the mechanism underlying neuroprotective effects of Nec-1 in POCD. Rats were treated with Nec-1 (6.25 mg/kg) 1 h prior to anesthesia. Open field test and Morris water maze were employed to detect the cognitive function. In this study, rats exposed to sevoflurane displayed cognitive dysfunction without changes in spontaneous activity; however, the sevoflurane-induced POCD could be relieved by Nec-1 pretreatment. Nec-1 decreased sevoflurane-induced calcium overload and calpain activity in the hippocampus. In addition, Nec-1 alleviated the expression of p-RIPK1, RIPK1, p-RIPK3, RIPK3, p-MLKL and MLKL. Furthermore, Nec-1 remarkably increased BDNF and p-TrkB/TrkB expression in the hippocampus of aged rats. Ultimately, our research manifests evidence that Nec-1 may play a neuroprotective role against sevoflurane-induced cognitive impairment via the increase of BDNF/TrkB and suppression of necroptosis-related pathway.

Tetrandrine ameliorated Alzheimer's disease through suppressing microglial inflammatory activation and neurotoxicity in the 5XFAD mouse

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disorder prevalent in the aged population. Tetrandrine is a natural metabolite isolated from herbal medicine Stephania tetrandra with various activities.

PURPOSE

In this study, we investigated the therapeutic role of tetrandrine in 5XFAD mouse, a transgenic model of AD.

METHODS

5XFAD mice were intraperitoneally injected with saline or different doses of tetrandrine (10, 20, and 40 mg/kg per 2 days) from the age of 5 months to 7 months followed by the determination of cognitive ability, amyloid plaque load, cell apoptosis, and inflammation in the brain. In vitro, the protective roles of tetrandrine against inflammatory activation of microglia and the resulting neurotoxicity were studied in BV2 cells and differentiated PC12 cells, respectively.

RESULTS

Morris water maze test showed that two months of tetrandrine treatment dose-dependently improved the cognitive ability of 5XFAD mice. Immunostaining against Aβ 1-42 demonstrated reduced amyloid plaque deposition in the brain of tetrandrine-treated 5XFAD mice. TUNEL assay revealed decreased cell apoptosis in the hippocampus after tetrandrine treatment. Further, RT-PCR showed that the ectopic transcription of inflammation-associated genes including TNFα, IL-1β, IL-6, COX-2, iNOS, and p65 was reversed in 5XFAD mice treated with tetrandrine. In vitro, Aβ 1-42 stimulated the secretion of inflammatory cytokines TNFα and IL-1β in microglial BV2 cells as determined by ELISA, which was suppressed by tetrandrine pre-treatment. Tetrandrine pre-treatment also inhibited the expression of TLR4, p65, iNOS, and COX-2 in BV2 cells induced by Aβ 1-42. Most importantly, treatment of PC12-derived neuron-like cells with conditional medium from Aβ 1-42-stimulated BV2 cells remarkably impaired cell viability and promoted cell apoptosis, which was attenuated by the conditional medium from BV2 cells with tetrandrine pre-treatment.

CONCLUSION

Collectively, findings in this study demonstrated that tetrandrine ameliorates AD by suppressing microglia-mediated inflammation and neurotoxicity.

Apoptosis inhibition is involved in improvement of sevoflurane-induced cognitive impairment following normobaric hyperoxia preconditioning in aged rats

Sevoflurane, a commonly used anesthetic agent has been confirmed to induce cognitive impairment in aged rats. Normobaric hyperoxia preconditioning has been demonstrated to induce neuroprotection in rats. The present study aimed to determine whether normobaric hyperoxia preconditioning could ameliorate cognitive deficit induced by sevoflurane and the possible mechanism by which it may exert its effect. A total of 66, 20-month-old male Sprague-Dawley rats were randomly divided into 3 groups (n=22 each): Rats in the control (C) and sevoflurane anesthesia (S) groups received no normobaric hyperoxia preconditioning before sevoflurane exposure, rats in the normobaric hyperoxia pretreatment (HO) group received normobaric hyperoxia preconditioning before sevoflurane exposure (95% oxygen for 4 continuous h daily for 6 consecutive days). The anesthesia rats (S and HO groups), were exposed to 2.5% sevoflurane for 5 h, while the sham anesthesia rats (C group) were exposed to no sevoflurane. The neurobehavioral assessment was performed using a Morris water maze test, the expressions of the apoptosis proteins were determined using western blot analysis, and the apoptosis rate and cytosolic calcium concentration were measured by flow cytometry. Normobaric hyperoxia preconditioning improved prolonged escape latency and raised the number of platform crossings induced by sevoflurane in the Morris water maze test, increased the level of bcl-2 protein, and decreased the level of bax and active caspase-3 protein, the apoptosis rate and cytosolic calcium concentration in the hippocampus 24 h after sevoflurane exposure. The findings of the present study may imply that normobaric hyperoxia preconditioning attenuates sevoflurane-induced spatial learning and memory impairment, and this effect may be partly related to apoptosis inhibition in the hippocampus. In conclusion, normobaric hyperoxia preconditioning may be a promising strategy against sevoflurane-induced cognitive impairment by inhibiting the hippocampal neuron apoptosis.

Tetrandrine attenuates hyperoxia-induced lung injury in newborn rats via NF-κB p65 and ERK1/2 pathway inhibition

Background

Bronchopulmonary dysplasia (BPD) is an important cause of respiratory illness in preterm newborns that results in significant morbidity and mortality. Hyperoxia is a critical factor in the pathogenesis of BPD, hyperoxia-induced lung injury model has similar pathological manifestations as human BPD. Tetrandrine (Tet) is known to suppress oxidative stress, apoptosis and inflammation. Thus it has been used to prevent organ injuries. However, the protective effect of Tet against hyperoxia-induced lung injury in newborn rats has not been reported.

Methods

A hyperoxia-induced lung injury model was established using newborn rats exposed to high O₂ levels. The models were treated with various concentrations of Tet, and a lung function test was conducted. Then, the lung tissues and blood were collected to detect the effect of Tet on cell apoptosis, inflammatory response, and fibrosis. The effect of Tet on nuclear factor-kappa B (NF-κB) and extracellular signal-regulated kinase1/2 (ERK1/2) pathways was also determined.

Results

Lung function was decreased in hyperoxia-induced rats, and Tet could reverse this inhibiting effect. For oxidative stress, Tet caused an increase in the levels of antioxidant enzymes. The apoptosis rate and apoptosis-related proteins were decreased in hyperoxia-induced rats after Tet treatment. Additionally, Tet treatment could reduce inflammatory factor levels, while increasing CD4⁺IFN-γ⁺ T cell levels and decreasing CD4⁺IL-4⁺ T cell levels. Tet treatment was also able to inhibit the expression of fibrosis-related markers and NF-κB and ERK1/2 pathways.

Conclusions

Tet demonstrated potent activity against hyperoxia-induced lung injury in newborn rats through NF-κB and ERK1/2 pathway inhibition.

Tetrandrine: a review of its anticancer potentials, clinical settings, pharmacokinetics and drug delivery systems

OBJECTIVES

Tetrandrine, a natural bisbenzylisoquinoline alkaloid, possesses promising anticancer activities on diverse tumours. This review provides systematically organized information on cancers of tetrandrine in vivo and in vitro, discuss the related molecular mechanisms and put forward some new insights for the future investigations.

KEY FINDINGS

Anticancer activities of tetrandrine have been reported comprehensively, including lung cancer, colon cancer, bladder cancer, prostate cancer, ovarian cancer, gastric cancer, breast cancer, pancreatic cancer, cervical cancer and liver cancer. The potential molecular mechanisms corresponding to the anticancer activities of tetrandrine might be related to induce cancer cell apoptosis, autophagy and cell cycle arrest, inhibit cell proliferation, migration and invasion, ameliorate metastasis and suppress tumour cell growth. Pharmaceutical applications of tetrandrine combined with nanoparticle delivery system including liposomes, microspheres and nanoparticles with better therapeutic efficiency have been designed and applied encapsulate tetrandrine to enhance its stability and efficacy in cancer treatment.

SUMMARY

Tetrandrine was proven to have definite antitumour activities. However, the safety, bioavailability and pharmacokinetic parameter studies on tetrandrine are very limited in animal models, especially in clinical settings. Our present review on anticancer potentials of tetrandrine would be necessary and highly beneficial for providing guidelines and directions for further research of tetrandrine.

Potential effect of herbal antidepressants on cognitive deficit: Pharmacological activity and possible molecular mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Cognitive symptom is a "core" symptom of major depressive disorder (MDD) patients with clear deficit in memory, social and occupational function, and may persist during the remitting phase. Therefore, the remission of cognitive symptom has been considered as one of the main objectives in the treatment of MDD. Herbal antidepressants have been used to treat MDD, and there has been great advances in the understanding of the ability of these herbs to improve cognitive deficit linked to brain injury and various diseases including depression, Alzheimer disease, diabetes and age-related disorders. This systematic review summarizes the evidence from preclinical studies and clinical trials of herbal antidepressants with positive effects on cognitive deficit. The potential mechanisms by which herbal antidepressants prevent cognitive deficit are also reviewed. This review will facilitate further research and applications.

MATERIALS AND METHODS

We conducted an open-ended, English restricted search of MEDLINE (PubMed), Web of Science and Scopus for all available articles published or online before 31 December 2019, using terms pertaining to medical herb/phytomedicine/phytochemical/Chinese medicine and depression/major depressive disorder/antidepressant and/or cognitive impairment/cognitive deficit/cognitive dysfunction.

RESULTS

7 prescriptions, more than 30 individual herbs and 50 phytochemicals from China, Japan, Korea and India with positive effects on the depressive state and cognitive deficit are reviewed herein. The evidence from preclinical studies and clinical trials proves that these herbal antidepressants exhibit positive effects on one or more aspects of cognitive defect including spatial, episodic, aversive, and short- and long-term memory. The action mode of the improvement of cognitive deficit by these herbal antidepressants is mediated mainly through two pathways. One pathway is to promote hippocampal neurogenesis through activating brain derived neurotrophic factor-tropomyosin-related kinase B signaling. The other pathway is to prevent neuronal apoptosis through the inhibition of neuro-inflammation and neuro-oxidation.

CONCLUSION

These herbal antidepressants, having potential therapy for cognitive deficit, may prevent pathological processes of neurodegenerative diseases. Furthermore, these herbal medicines should provide a treasure trove, which will accelerate the development of new antidepressants that can effectively improve cognitive symptom in MDD. Studies on their molecular mechanisms may provide more potential targets and therapeutic approaches for new drug discovery.

Silencing SP1 Alleviated Sevoflurane-Induced POCD Development via Cholinergic Anti-inflammatory Pathway

Postoperative cognitive dysfunction (POCD) is a common complication induced by anesthesia or surgery, which affects the concentration, cognition and memory of patients. Sevoflurane, a clinical anesthetic, could stimulate neuro-inflammation and lead to POCD. Recent studies found that specificity protein 1 (SP1) participates in the development of neurological diseases. Our study aims to elucidate the role of SP1 in sevoflurane-induced POCD pathogenesis. We anesthetized Sprague-Dawley rats and treated the primary hippocampal neurons with sevoflurane to construct the in vivo and in vitro POCD models. Besides, the expression and regulatory mechanism of SP1 in the pathogenesis of POCD were explored. According to the results, sevoflurane anesthesia impaired the cognitive functions of rat, significantly elevated SP1 expression and inactivated the cholinergic anti-inflammatory pathway (CAP) both in vivo and in vitro. Moreover, the sevoflurane-treated rats and neurons also exhibited obvious inflammatory responses and enhanced apoptosis. Loss-of-function assay indicated that SP1 knockdown rescued the deactivation of CAP and alleviated the sevoflurane-induced neuro-inflammation and apoptosis in rat hippocampus. Generally, our study documented that the sevoflurane-induced SP1 up-regulation affected the activation of CAP, leading to the aggravated neuro-inflammation and apoptosis. This may provide a novel sight for POCD therapy.

Hirsutanol A exhibits neuroprotective activities against sevoflurane-induced neurotoxicity in aged rats

The neurotoxicity of the inhaled anesthetic, sevoflurane, has been documented in a number of studies. In this study, we conducted experiments to investigate whether Hirsutanol A (HA), a sesquiterpene compound from the fungus, Chondrostereum sp., can provide protection from sevoflurane-induced neurological toxicity in aged rats, and analyzed the underlying mechanisms. The cognitive dysfunction of rats following sevoflurane exposure was evaluated by behavioral tests. The neuronal cell survival was determined by Nissl staining. In addition, human neuroblastoma H4 cells were exposed to sevoflurane to establish an in vitro model. Apoptotic marker expression in hippocampal tissue was determined by western blotting. Cell apoptosis in vitro was also examined by TUNEL assay and flow cytometry. The expression and translocation of Nrf2 were examined by both western blot and immunofluorescence staining. Our results show that HA significantly attenuated sevoflurane-induced cognitive impairment in aged rats. In addition, HA treatment decreased sevoflurane-induced neuronal apoptosis in the hippocampus and alleviated Aβ accumulation. Our results also show that the neuroprotective effect of HA is associated with the activation of Nrf2 signaling. Human neuroblastoma H4 cells were used as a model to examine the protective activity of HA against sevoflurane-induced neurotoxicity. In addition, our results show that the inhibition of Nrf2 by a specific inhibitor or targeting siRNA significantly compromises the attenuating effect of HA on sevoflurane-induced cell apoptosis and Aβ accumulation. Our results suggest that HA may function as a neuroprotective agent against sevoflurane-induced neurotoxicity.

Tetrandrine Suppresses Transient Receptor Potential Cation Channel Protein 6 Overexpression- Induced Podocyte Damage via Blockage of RhoA/ROCK1 Signaling

Objective

Podocyte damage is common in many renal diseases characterized by proteinuria. Transient receptor potential cation channel protein 6 (TRPC6) plays an important role in renal function through its regulation of intracellular Ca²⁺ influx and RhoA/ROCK pathways. Chinese herb Stephania tetrandra, with the main active component being tetrandrine, has been used for the treatment of various kidney diseases for several years and has shown a positive effect. This study aimed at investigating the effect and mechanism of tetrandrine in podocyte damage induced by high expression of TRPC6.

Methods

Immortalized, differentiated murine podocytes, MPC5 were treated with valsartan (0–800 μM) and tetrandrine (0–40 μM) for 48 h. The maximum safe concentrations of valsartan and tetrandrine were selected using a cell viability assay. MPC5 podocytes stably expressing TRPC6 were constructed using a lentivirus packaging system, followed by treatment with valsartan, tetrandrine, and Y-27632 for 48 h and U73122 (10 μM) for 10 min. The RhoA/ROCK pathway and podocyte-specific proteins (nephrin and synaptopodin) levels were quantified. Podocyte apoptosis and intracellular Ca²⁺ concentration were measured.

Results

Maximum safe concentrations of 100 μM valsartan and 10 μM tetrandrine showed no observable toxicity in podocytes. MPC5 podocytes stably expressing TRPC6 had higher intracellular Ca²⁺ influx, apoptotic percentages, and expression of RhoA/ROCK proteins, but lower expression of nephrin and synaptopodin proteins. U73122 treatment for 10 min did not inhibit TRPC6, but suppressed RhoA/ROCK protein. Y-27632 decreased ROCK1 expression, but did not influence the expression of TRPC6 protein. Both 100 μM valsartan and 10 μM tetrandrine for 48 h significantly inhibited intracellular Ca²⁺ influx, apoptosis, and RhoA/ROCK pathway, and increased nephrin and synaptopodin proteins in podocytes stably expressing TRPC6.

Conclusion

Elevated TRPC6 expression can lead to podocyte injury by inducing intracellular Ca²⁺ influx and apoptosis of podocytes, and this effect may be mediated by activation of the RhoA/ROCK1 pathway. Tetrandrine can alleviate podocyte injury induced by TRPC6 expression through inhibition of the RhoA/ROCK pathway, suggesting a protective role in podocyte damage.

Ampelopsin alleviates sevoflurane-induced cognitive dysfunction by mediating NF-κB pathway in aged rats

BACKGROUND

Cancer-induced bone pain (CIBP) is the pain caused by bone metastasis from malignant tumors, and the largest source of pain for cancer patients. miR-300 is an important miRNA in cancer. It has been shown that miR-300 regulates tumorigenesis of various tumors.

PURPOSE

This study aims to investigate the role of miR-300 in CIBP and its underlying molecular mechanisms in vitro and in vivo.

METHODS

We constructed CIBP model in rats and investigated the mechanism through which miR-300 affects CIBP. We first examined expression level of miR-300 in CIBP rats and then tested the effect of its overexpression. Next, we identified the target of miR-300 using TargetScan analysis and double luciferase assay. Finally, we studied genetic interactions between miR-300 and its target and their roles in CIBP.

RESULTS

We found that miR-300 was downregulated in CIBP rats. Overexpression of miR-300 significantly attenuated cancer-induced neuropathic pain (p < 0.01). Furthermore, TargetScan analysis and double luciferase assay show High Mobility Group Box 1 (HMGB1) is a target of miR-300. Notably, HMGB1 is overexpressed in CIBP rats, while up-regulation of miR-300 significantly suppresses expression of HMGB1 (p < 0.01). Moreover, knockdown of HMGB1 by siRNA significantly relieves cancer-induced neuropathic pain in rats (p < 0.01). On the other hand, HMGB1 overexpression partially blocked the effect of miR-300 on cancer-induced nerve pain.

CONCLUSION

miR-300 relieves cancer-induced neuropathic pain by inhibiting HMGB1 expression. These results may be beneficial for the treatment of CIBP in clinical practice.

A critical review: traditional uses, phytochemistry, pharmacology and toxicology of Stephania tetrandra S. Moore (Fen Fang Ji)

ABSTRACT

Stephania tetrandra S. Moore (S. tetrandra) is distributed widely in tropical and subtropical regions of Asia and Africa. The root of this plant is known in Chinese as "Fen Fang Ji". It is commonly used in traditional Chinese medicine to treat arthralgia caused by rheumatism, wet beriberi, dysuria, eczema and inflamed sores. Although promising reports have been published on the various chemical constituents and activities of S. tetrandra, no review comprehensively summarizes its traditional uses, phytochemistry, pharmacology and toxicology. Therefore, the review aims to provide a critical and comprehensive evaluation of the traditional use, phytochemistry, pharmacological properties, pharmacokinetics and toxicology of S. tetrandra in China, and meaningful guidelines for future investigations.

Anesthetics: from modes of action to unconsciousness and neurotoxicity

Modern anesthetic compounds and advanced monitoring tools have revolutionized the field of medicine, allowing for complex surgical procedures to occur safely and effectively. Faster induction times and quicker recovery periods of current anesthetic agents have also helped reduce health care costs significantly. Moreover, extensive research has allowed for a better understanding of anesthetic modes of action, thus facilitating the development of more effective and safer compounds. Notwithstanding the realization that anesthetics are a prerequisite to all surgical procedures, evidence is emerging to support the notion that exposure of the developing brain to certain anesthetics may impact future brain development and function. Whereas the data in support of this postulate from human studies is equivocal, the vast majority of animal research strongly suggests that anesthetics are indeed cytotoxic at multiple brain structure and function levels. In this review, we first highlight various modes of anesthetic action and then debate the evidence of harm from both basic science and clinical studies perspectives. We present evidence from animal and human studies vis-à-vis the possible detrimental effects of anesthetic agents on both the young developing and the elderly aging brain while discussing potential ways to mitigate these effects. We hope that this review will, on the one hand, invoke debate vis-à-vis the evidence of anesthetic harm in young children and the elderly, and on the other hand, incentivize the search for better and less toxic anesthetic compounds.

Down-Regulation of Mir-145 Improves Learning and Memory Abilities in Epileptic Rats by Regulating Hippocampal Neuron Apoptosis

OBJECTIVES

To investigate effect of miR-145 on learning and memory ability in rats with epilepsy.

METHODS

Rats with epilepsy were induced by lithium chloride-pilocarpine. miR-145 antagomir and antagomir-control were injected into epileptic brains by the stereotactic technique, respectively. Then, rats were divided into a normal group (N), epilepsy group (Ep), miR-145 antagomir group (A) and antagomir-control group (C). After 1 and 7 days of treatment, the expression of miR-145 and Caspase-9 were detected, and the apoptosis of hippocampal neurons in CA1 of hippocampus was detected. After 7 days of treatment, the learning and memory abilities of rats was measured by using the Morris water maze test.

RESULTS

The rat epilepsy model was successfully constructed. Compared with the N group, the target quadrant time and platform crossing times were reduced and the expression of miR-145 and Caspase-9 was increased in the epilepsy groups (P < 0.05). Compared with the Ep and C groups, the target quadrant time and platform crossing times were increased and the expression of miR-145 and Caspase-9 was down-regulated in the A group (P < 0.05). The number of apoptotic hippocampal neurons in the hippocampal CAl area of the Ep group was more than that in the N group and in the A group was less than that in the C group at 1 and 7 days after modeling respectively (P < 0.05).

CONCLUSIONS

Down-regulated miR-145 improved the apoptosis of hippocampal neurons by reducing the Caspase-9 expression in hippocampus and further affected learning and memory abilities of rats with epilepsy.

Sevoflurane preconditioning ameliorates lipopolysaccharide-induced cognitive impairment in mice

Systemic inflammation induces brain neuronal inflammation, in turn causing acute cognitive disorders. Furthermore, neuronal inflammation is one cause of postoperative cognitive disorder (POCD) and delirium. However, no sufficiently established pharmacological treatment is available for neurocognitive inflammation. This study evaluated the possible neuroprotective effects of preconditioning with sevoflurane anesthesia on cognition and neuroinflammatory changes in an animal model of lipopolysaccharide (LPS)-induced systemic inflammation. Adult mice were randomly divided into (1) control, (2) 2% sevoflurane preconditioning for 1 h, (3) intraperitoneal 5 mg/kg LPS injection, and (4) 2% sevoflurane preconditioning for 1 h + LPS injection groups. At 24 h after 5 mg/kg LPS injection, microglial activation based on ionized calcium-binding adapter molecule 1 (Iba-1) expression in the hippocampus was determined using immunostaining and immunoblotting. IL-1β and IL-6 immunoblotting were used as inflammation markers, and β-site of amyloid precursor protein cleaving enzyme 1 (BACE1) immunoblotting was performed to evaluate amyloid β-protein (Aβ) accumulation. Long-term cognitive impairment was evaluated using fear conditioning tests. Intraperitoneal LPS increased levels of Iba-1 (150%), inflammation markers (160%), and Aβ accumulation (350%), and sevoflurane preconditioning suppressed these increases. Systemic LPS caused learning deficits. Sevoflurane also maintained long-term memory in mice receiving LPS injection. Sevoflurane preconditioning prevented long-term memory impairment in the mouse model administered systemic LPS by decreasing excessive microglial activation, inflammation, and Aβ accumulation. This study supports the hypothesis that sevoflurane preconditioning might also be beneficial for neuronal inflammation. Sevoflurane might be beneficial for reducing delirium and POCD.