Anesthesia and the Developing Brain: A Review of Sevoflurane-induced Neurotoxicity in Pediatric Populations

BIS Guided Titration of Sevoflurane in Pediatric Patients Undergoing Elective Surgery: A Randomized Controlled Trial

BACKGROUND

In pediatric patients, the use of processed EEG monitoring may reduce the amount of anesthesia administered while maintaining adequate depth of anesthesia.

AIMS

The primary aim of this study was to evaluate whether use of a BIS monitor to guide sevoflurane administration might reduce the average end tidal sevoflurane concentration used in children 4-18 years of age.

METHODS

Participants in three age groups (4-8, 9-12, and 13-18 years) were randomized to either the BIS guided group or the control group. Use of sevoflurane as the primary maintenance anesthetic was the only requirement in both arms. In the BIS guided group, sevoflurane was titrated to achieve a target BIS value of 45-60 during the maintenance period. In the control arm, clinicians were blinded to the BIS value. Primary outcome was mean end-tidal sevoflurane concentration during maintenance phase of anesthesia. Secondary assessments included time to discharge and the readiness and quality of recovery as assessed by the Pediatric Anesthesia Emergence Delirium scale, the modified Aldrete Score, and the Wong-Baker FACES scale. An intention-to-treat analysis was used to analyze and compare groups.

RESULTS

A total of 180 participants were randomized. Following randomization, 10 participants did not undergo any study procedures, leaving 84 participants in the BIS guided group and 86 participants in the control group. Across all age groups, the average end-tidal sevoflurane concentration was less in the BIS guided group compared to control (4-8 years: 2.2% ± 0.3% vs. 2.4% ± 0.4%, -0.3% [-0.4%, -0.1%]; 9-12 years: 1.7% ± 0.5% vs. 2.1% ± 0.6%, -0.4% [-0.7%, -0.1%]; 13-18 years: 1.6% ± 0.4% vs. 1.9% ± 0.5%, -0.3% [-0.5%, -0.1%]). No differences in recovery outcomes between treatment groups were observed.

CONCLUSIONS

In pediatric participants, the BIS guided group reported a lower average end-tidal sevoflurane concentration compared to control, though no significant differences in recovery profile were noted.

CLINICAL IMPLICATIONS

The Bispectral Index (BIS) is a processed EEG tool that can be used to titrate general anesthesia to achieve desired anesthetic depth. Brain monitoring with BIS resulted in lower average end-tidal sevoflurane concentrations in children aged 4-18 years undergoing general anesthesia.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04810481.

Mitophagy impairment drives microglia activation and results in cognitive deficits in neonatal mice following sevoflurane exposure

Sevoflurane exposure induces cognitive deficits in neonatal mice. Mitophagy was closely correlated to sevoflurane inhalation induced neurotoxicity in developing brains. However, the underlying mechanisms have not been fully elucidated. In this study, we attempted to clarify the role of mitophagy in neonatal mice undergoing sevoflurane exposure. BV2 microglial cells were cultured, and mcherry-EGFP-LC3B adenovirus were transfected. The results showed that the fluorescence intensity of GFP was markedly increased after sevoflurane exposure, and rapamycin administration could mitigate this effect. The mitophagy flux test showed that sevoflurane exposure reduced the degree of colocalization between Mito-Traker and Lyso-Traker fluorescent, while which was elevated by rapamycin treatment. The immunofluorescence assay suggested that sevoflurane inhalation resulted in the significant decrease of autolysosome formation, which was sharply enhanced in SEV group after rapamycin treatment. Meanwhile, sevoflurane inhalation shifted microglial M1/M2 phenotypic polarization, and rapamycin administration reversed this status. Moreover, the degree of colocalization among Iba-1, Synaptophysin (Syn) and lysosomal-associated membrane protein 1 (Lamp1) was increased after sevoflurane exposure, and that was reduced following rapamycin treatment. The behavioral performance was worse after sevoflurane inhalation in neonatal mice, and rapamycin treatment effectively improved the cognitive outcome. Collectively, these findings demonstrated that mitophagy impairment induced by sevoflurane exposure promoted microglia M1 phenotypic polarization and enlarged phagocytosis, and resulted in cognitive deficits, while rapamycin administration effectively reversed this tendency.

IL-17A is a key regulator of neuroinflammation and neurodevelopment in cognitive impairment induced by sevoflurane

Increasing numbers of animal studies have shown that repeat sevoflurane exposure during developmental stage may lead to long-term cognitive impairment. Nevertheless, the exact pathogenesis remains unclear. Interleukin 17A (IL-17A) has been associated with cognitive decline in various neurological disorders. Here we found that the expression of IL-17A was up-regulated in hippocampus of sevoflurane exposed neonatal mice. Genetic deletion of IL-17A or inhibition of IL-17A improved behavioral function and down-regulated neuroinflammation related genes, interleukin 1β (IL-1β), interleukin 6 (IL-6), Nicotinamide adenine dinucleotide phosphate(NADPH) oxidase 2 (NOX2) and NADPH oxidase 4 (NOX4) in hippocampus of sevoflurane exposed neonatal mice. Moreover, negative regulation of IL-17A/Interleukin 17A receptor(IL-17RA) promoted the extracellular signal-regulated protein kinase (ERK) signaling pathway and nucleation of cyclic adenosine monophosphate (cAMP) response element-binding (CREB) in neurons of cognitive impaired mice. Knockdown of IL-17A in vivo identified neurons-localized IL-17A as a major factor in neuroinflammation and neurodevelopment. Collectively, our results suggested that IL-17A was required for the pathogenesis of neuroinflammatory response and identify IL-17A as a potential therapeutic target for cognitive impairment exposed by general anesthetics during infancy.

Opposite effects of sevoflurane at high and low concentration on the airway inflammation in juvenile asthma rats: A TMT-based proteomics analysis study

BACKGROUND

The incidence of sevoflurane-related adverse respiratory events in children with asthma is notably high. During different phases of sevoflurane anesthesia, asthmatic children's airways are exposed to varying concentrations of the anesthetic. However, the specific effects of different concentrations of sevoflurane on the developing airways with asthmatic hyperreactivity have not been systematically studied.

METHODS

An ovalbumin (OVA)-induced juvenile rat asthma model was established to evaluate the impact of varying sevoflurane concentrations on airway irritation symptoms, ventilation, pathological scoring, and inflammation. Tandem mass tag (TMT)-based quantitative proteomics and bioinformatics analyses were conducted, with key protein expressions validated by western blot.

RESULTS

Sevoflurane alleviated airway irritation symptoms in OVA-treated rats in a concentration-dependent manner. At 3.2 %, sevoflurane significantly reduced peribronchial inflammation, while 0.4 % sevoflurane exacerbated hypoxia, peribronchial injury, and inflammation. Proteomic analysis identified 54 overlapping differentially expressed proteins (DEPs), with three (serine protease inhibitor (SerpinA3L), major histocompatibility complex 1 (MHC1), and major histocompatibility complex 2 (MHC2)) being upregulated in the 3.2 % sevoflurane group but downregulated in the 0.4 % sevoflurane group. DEPs were predominantly linked to lysosomal and phagosomal pathways, as well as antigen processing and presentation. Three key hub proteins-cathepsin (CAT), vav guanine nucleotide exchange factor 1 (VAV1), and C-reactive protein (CRP)-were identified, and their expression levels were validated, matching the bioinformatics analysis results.

CONCLUSIONS

Our findings demonstrate that sevoflurane exerts opposing effects on the airways of juvenile asthmatic rats, depending on the concentration. MHC1, MHC2, and VAV1 emerged as crucial mediators of these differential effects, suggesting their potential as targets for understanding sevoflurane's impact on asthmatic airways.

Genetic instability of a single exposure to sevoflurane at different concentrations in monitored mice

Sevoflurane is an inhalation anesthetic widely used for general anesthesia, but its genotoxic potential is controversial in clinical studies. It is unknown whether the effects are due to surgery or the anesthetic. Thus, for the first time, the present study investigated genotoxicity in peripheral blood cells and in target organs (liver, lung, and kidney) and micronucleus (MN) in the bone marrow of a single exposure to sevoflurane at three different concentrations in monitored mice. Ninety Swiss mice were distributed into the following groups: exposure to sevoflurane at 3.3% (low), 4.5% (intermediate), and 6.0% (high) in 40% oxygen (O2) for 2 h; negative control (no exposure); negative control with O2; and positive control. The exposed animals were heated, monitored for vital signs (temperature, O2 saturation, heart rate/pulse, and respiratory rate), and anesthetized via a modern low-flow digital system. Mice were euthanized 2 and 24 h after exposure for evaluation by the comet assay and MN test, respectively. No DNA damage occurred in the 3.3% group for any of the organs evaluated, and no genotoxic or mutagenic effects were observed at any sevoflurane concentration in the peripheral blood or liver cells. However, a significant increase in DNA damage was observed at higher concentrations in kidney (4.5%) and lung cells (6.0%) and in the MN frequency (groups 4.5% and 6.0%). No cytotoxicity or histological alterations were observed. In conclusion, high concentrations of sevoflurane induce DNA damage, but concentrations equivalent to those used in clinical practice do not demonstrate genotoxic or mutagenic effects.

Gyosaponin ameliorates sevoflurane anesthesia-induced cognitive dysfunction and neuronal apoptosis in rats through modulation of the PI3K/AKT/mTOR pathway

BACKGROUND

Sevoflurane (Sev) is an inhalational anesthetic for surgical procedures where it can trigger cognitive dysfunction and neuronal apoptosis. Gyosaponin (GpS) was studied for its effects on brain morphology and cognitive behaviors in Sev-anesthetized rats.

METHODS

Male Sprague-Dawley rats were induced by 3 % Sev anesthesia, and 25 mg/kg and 100 mg/kg GpS were injected into the rats by tail vein. The in vitro model of Sev anesthesia was constructed by treating primary rat hippocampal neurons with 4.1 % Sev in the presence of GpS (5, 10, and 20 μM). The neuroprotective effects of GpS against Sev-induced cognitive deficits in rats were evaluated using the open field and Morris water maze tests. The apoptosis of hippocampal neurons was observed using HE staining and TUNEL assay. Apoptosis-related proteins and proteins related to the PI3K/Akt/mTOR pathway were determined via Western blot. Also, pro-inflammatory factors were measured via ELISA.

RESULTS

GpS diminished the Sev-triggered apoptosis in neurons and Cleaved caspase-3, BAX, TNF-α, IL-6, lessened oxidative stress damage, and stimulated the PI3K/Akt/mTOR pathway. GpS therapy markedly enhanced learning and memory abilities in rats suffering from Sev-related cognitive impairments.

CONCLUSION

GpS ameliorates Sev-induced neurotoxicity and cognitive dysfunction by modulating the PI3K/Akt/mTOR pathway and alleviating neuronal apoptosis and oxidative stress.

Novel Perspective on Sevoflurane-Induced Cognitive Dysfunction: Implications of Neuronal SIRPα and Microglial Synaptic Remodeling

This study aims to investigate the role of neuronal SIRPα and microglial synaptic remodeling in sevoflurane-induced cognitive dysfunction in newborn mice. Newborn mice were exposed to sevoflurane, followed by behavioral assessments and single-cell transcriptome sequencing of cortical cells. Lentivirus-mediated overexpression of neuronal SIRPα and assessment of the microglial morphology and synaptic function were conducted. Sevoflurane exposure resulted in social cognitive impairments without affecting motor coordination. Transcriptomic analysis revealed no significant changes in cortical microglial cells or neurons. However, sevoflurane inhibited nonsynaptic synapse modification by microglia. Overexpression of neuronal SIRPα enhanced microglial function, promoted neuron development, and ameliorated cognitive impairments. SCENIC analysis identified a correlation between IRF8 and SIRPα expression. This study sheds light on the involvement of neuronal SIRPα and microglial synaptic remodeling in sevoflurane-induced cognitive dysfunction. Understanding these mechanisms offers new avenues for exploring cognitive impairment pathways and potential therapeutic targets.

Morphometric analysis of the female reproductive tract: influence of long-term inhalation of trace amounts of sevoflurane

Sevoflurane is extensively employed as an inhalation anesthetic in medical practices, due to its promising pharmacokinetics. Conversely, the data regarding effects of prolonged exposure to trace amounts of sevoflurane on the female reproductive system is obscure. Therefore, this study aimed to investigate the reproductive toxicity and underlying mechanism of long-term sevoflurane inhalation in female rats. A total 60 SPF grade SD female rats were randomly alienated into four equal groups as control group (A), 50 ppm sevoflurane group (B), 150 ppm sevoflurane group (C), and 300 ppm sevoflurane groups (D). Ovaries and uterine organs were collected for gross as well as histopathological analysis, western blotting, and immuno-histochemistry evaluation. Results revealed that pregnancy rate, number of fetuses (fetal mice) and general body weight of group B, C, and D were substantially lower (P < 0.05), while were compared with control. On the contrary, estrous period in groups B, C, D was shortened noticeably (P < 0.05), and estrus interval and cycle were significantly longer (P < 0.05). In fact, the ovarian and uterine coefficients of group B, C and D were significantly reduced as compared with control. However, ovarian and uterine histomorphology remained normal in control group, while obvious pathological alterations were detected in groups B, C, and D. Although, the expression of SOD protein in the ovarian and uterine tissues of groups B, C, and D was significantly reduced (P < 0.05), in contrast to group A. However, the MDA protein expression increased significantly (P < 0.05) as compared with group A. While expression of apoptosis-related genes (Bcl2 and Bax) and humoral immunity related genes (IL-6, IL-10 and TNF-α) showed highest elevation in groups exposure with sevoflurane (p < 0.001) in comparison to control. Conclusively, long-term inhalation of trace amounts of sevoflurane is toxic to female reproductive system and can severely affect reproductive organs and fertility by induction of oxidative stress and apoptosis.

Downregulation of circTLK1 improves the impairments in learning and memory induced by anesthetics via regulating miR-374b-5p expression and reducing neuroinflammation

BACKGROUND

Sevoflurane (Sev) is a common anesthetic used during surgery, but research on its induction of neurotoxicity and learning memory impairment is insufficient. This study aimed to explore the role of Circular RNA tousled like kinase 1 (circTLK1) and its target microRNA (miR)-374b-5p in Sev-induced neurotoxicity and learning memory impairment.

METHODS

Mouse hippocampal neuronal HT22 cells and SD rats were treated with Sev. Levels of circTLK1 and miR-374b-5p were detected using RT-qPCR. The concentration of inflammatory factors was determined using ELISA. Cell viability and apoptosis were analyzed using CCK-8 and flow cytometry. Targeting relationship between circTLK1 and miR-374b-5p was validated using dual-luciferase reporter assays and RIP experiments. The Morris water maze test was used to assess the learning and spatial memory abilities of rats.

RESULTS

The results indicated that Sev treatment stimulated neuroinflammation and oxidative stress while increasing circTLK1 levels and decreasing miR-374b-5p levels in both rats and HT22 cells. Silencing circTLK1 alleviated the decrease in cell viability, increased apoptosis rates, and raised concentrations of inflammatory factors caused by Sev treatment. In in vivo experiments, silencing circTLK1 was also found to counteract the oxidative stress, neuroinflammation, and learning and memory impairment induced by Sev treatment in rats. Additionally, circTLK1 was shown to interact with miR-374b-5p, and inhibiting miR-374b-5p could counteract the neuroprotective effects of si-circTLK1.

CONCLUSION

This research suggested that silencing circTLK1 can mitigate Sev-induced neurotoxicity and learning memory impairment by modulating miR-374b-5p.

Comprehensive Analysis of Bulk RNA-Seq and Single-Cell RNA-Seq Data Unveils Sevoflurane-Induced Neurotoxicity Through SLC7A11-Associated Ferroptosis

Sevoflurane's potential impact on cognitive function and neurodevelopment, especially in susceptible populations such as infants and the elderly, has raised widespread concern. This study focuses on how sevoflurane induces ferroptosis in astrocytes and identifies solute carrier family 7 member 11 (SLC7A11) as a mediator of ferroptosis, providing new insights into sevoflurane-related neurotoxic pathways. We analysed single-cell sequencing (scRNA-seq) data from sevoflurane-exposed mice and control mice, supplemented with bulk RNA-seq data, to assess gene expression alterations. Additionally, pregnant mice were subjected to in vivo experiments, and in vitro studies using U251 astrocytoma cells were conducted to evaluate sevoflurane's neurotoxic effects on offspring, focusing on ferroptosis markers and SLC7A11 expression. Sevoflurane exposure led to learning, memory and behavioural deficits in offspring, associated with decreased SLC7A11 expression and increased signs of ferroptosis. In U251 cells, sevoflurane reduced cell viability, increased reactive oxygen species (ROS) levels and affected the expression of ferroptosis regulatory factors, supporting the hypothesis that sevoflurane induces astrocyte ferroptosis through SLC7A11 modulation. Molecular docking experiments suggest a direct interaction between sevoflurane and SLC7A11. This study provides mechanistic insights into sevoflurane-induced neurotoxicity, emphasising the importance of SLC7A11 in regulating astrocyte ferroptosis. Our findings highlight the potential for targeting ferroptosis pathways to mitigate the adverse effects of sevoflurane anaesthesia.

Sevoflurane promotes neuronal ferroptosis via upregulation of PLIN4 to modulate the hippo signaling pathway

BACKGROUND

Sevoflurane is a widely used inhalation anesthetic associated with neuronal damage, cognitive impairment and neurodegenerative diseases, with iron overload reported to contribute to these adverse effects. However, the mechanisms of iron-dependent cell death (ferroptosis) in sevoflurane-induced neurotoxicity remain poorly understood.

METHODS

The role of PLIN4, a protein associated with neurodegeneration, in sevoflurane-induced neuronal damage was investigated using cultured mouse hippocampal neurons (HT22). PLIN4 knockdown or overexpression was performed through vector transfection, and PLIN4 transcription and expression levels after sevoflurane treatment and knockdown experiments were assessed via RT-qPCR, immunostaining, and western blot to evaluate its impact on ferroptosis. Transmission electron microscopy was used to assess cellular morphology and measure Fe2+ levels.

RESULTS

Sevoflurane treatment significantly increased PLIN4 expression in hippocampal neurons and induced ferroptosis. Silencing PLIN4 reduced ferroptosis and partially reversed sevoflurane's inhibition of the Hippo signaling pathway. Specifically, sevoflurane treatment led to a 2.9-fold increase in PLIN4 mRNA levels. Furthermore, higher PLIN4 levels upregulated ferroptosis in hippocampal neurons by inhibiting the Hippo pathway.

CONCLUSION

Our study indicates that sevoflurane promotes ferroptosis in neurons by upregulating PLIN4 and modulating the Hippo signaling pathway. These findings provide insights into the potential development of interventions to prevent anesthesia-related cognitive impairments and neurodegeneration.

Dexmedetomidine Alleviates the Long-Term Neurodevelopmental Toxicity Induced by Sevoflurane in the Developing Brain

INTRODUCTION

Sevoflurane is an extensively used anesthetic for pediatric patients; however, numerous studies showed that sevoflurane (SEVO) may cause long-term neurodevelopmental toxicity. Dexmedetomidine (DEX) has been shown to be protective against SEVO-induced neurotoxicity, but the mechanism remains unclear. The effects and mechanisms of different DEX administration routes on SEVO-induced neurotoxicity and long-term cognitive defects were determined and further investigated the role of sex in these processes.

METHODS

Male and female Sprague Dawley rats at postnatal day 7 (PND7) received an intraperitoneal injection of DEX (10 μg/kg) before or after exposure to 2.5% SEVO for 6 h, or before and after SEVO exposure. The respiratory and mortality rates of the pups were recorded during anesthesia. Neuroapoptosis was evaluated by TdT-mediated dUTP nick-end labeling staining. Immunohistochemistry and immunofluorescence were employed to detect the expression of caspase-3 in neuronal cells and neurons. The expression of GSK-3β and DISC1 was determined by Western blotting or RT-qPCR. Morris water maze (MWM) test was used to evaluate the learning and memory ability of rats until they were 3 weeks and 5 weeks old.

RESULTS

Compared with the control group, exposure to 2.5% SEVO resulted in increased neuroapoptosis and decreased the expression of DISC1 at levels of mRNA and protein and phosphorylated GSK-3β in the developing brain. SEVO exposure during critical neurodevelopmental periods could cause persistent cognitive defects in adolescent male and female rats and inhibited DISC1 and phosphorylated GSK-3β protein expression. The neurotoxic impacts of SEVO were lessened by the administration of DEX (10 μg/kg) before or after exposure.

CONCLUSION

Our findings suggest that DEX (10 μg/kg) mitigates the neurotoxic effects of SEVO on the developing rat brain as well as postnatal cognitive defects by regulating the DISC1/GSK-3β signaling.

Repeated postnatal sevoflurane exposure impairs social recognition in mice by disrupting GABAergic neuronal activity and development in hippocampus

BACKGROUND

Repeated exposure to sevoflurane during early developmental stages is a risk factor for social behavioural disorders, but the underlying neuropathological mechanisms remain unclear. As the hippocampal cornu ammonis area 2 subregion (CA2) is a critical centre for social cognitive functions, we hypothesised that sevoflurane exposure can lead to social behavioural disorders by disrupting neuronal activity in the CA2.

METHODS

Neonatal mice were anaesthetised with sevoflurane 3 vol% for 2 h on postnatal day (PND) 6, 8, and 10. Bulk RNA sequencing of CA2 tissue was conducted on PND 12. Social cognitive function was assessed by behavioural experiments, and in vivo CA2 neuronal activity was recorded by multi-channel electrodes on PND 60-65.

RESULTS

Repeated postnatal exposure to sevoflurane impaired social novelty recognition in adulthood. It also caused a decrease in the synchronisation of neuronal spiking, gamma oscillation power, and spike phase-locking between GABAergic spiking and gamma oscillations in the CA2 during social interaction. After sevoflurane exposure, we observed a reduction in the density and dendritic complexity of CA2 GABAergic neurones, and decreased expression of transcription factors critical for GABAergic neuronal development after.

CONCLUSIONS

Repeated postnatal exposure to sevoflurane disturbed the development of CA2 GABAergic neurones through downregulation of essential transcription factors. This resulted in impaired electrophysiological function in adult GABAergic neurones, leading to social recognition deficits. These findings reveal a potential electrophysiological mechanism underlying the long-term social recognition deficits induced by sevoflurane and highlight the crucial role of CA2 GABAergic neurones in social interactions.

Early Cognitive Function after Deep Sedation Using Different Anesthetic Agents in Pediatric Patients: A Prospective, Randomized Controlled Trial

Background and Objectives: The impact of anesthetic agents on memory and cognitive function following general anesthesia is of great interest, particularly regarding their effects on the developing pediatric brain. While numerous studies have examined the relationship between anesthetic drugs and brain function, research focusing on early cognitive function following sedation remains limited. Materials and Methods: This study was a prospective, randomized controlled trial involving 148 pediatric patients scheduled for hematological procedures, specifically bone marrow aspiration (BMA) and intrathecal chemotherapy (ITC). Patients were divided into two groups based on the primary anesthetic used: the inhalational sedation group (IHG), in which sevoflurane was used, and the intravenous sedation group (IVG), which received propofol infusion. Apart from the main anesthetic agent, all sedation methods were consistent across both groups. A cognitive function test administered before sedation involved memorizing four distinct images, each associated with a different number. Then, the patients were asked to identify the omitted image upon awakening in the recovery room. Herein, this pre- vs. post-sedation test is called the early recognition assessment (ERA) tool. The primary outcome was the correct response rate after sedation for the two groups. Secondary outcomes included the sedation score, the behavior response score, and the correct response rates according to the number of sedation procedures. Results: This study included 130 patients in the final analysis, with 74 originally assigned to each group. The initial cognitive assessment revealed no significant difference in performance between the anesthetic agents. In addition, no differences were observed in the rates of correct responses or post-sedation scores after repeated procedures. However, the IVG demonstrated higher behavior response scores compared to the IHG. Conclusions: There were no significant differences in the rates of correct responses using the ERA tool between the two groups, irrespective of the number of sedation procedures performed. While some differences were noted in preoperative, intraoperative, and post-anesthesia care, these did not significantly impact the cognitive outcomes measured.

The clinical effect of sevoflurane anesthesia with laryngeal mask airway in the extraction of teeth in children

Objective

To evaluate the effect of sevoflurane general anesthesia with laryngeal mask airway in the extraction of teeth.

Methods

A retrospective analysis was performed on 88 children who underwent extraction of teeth in the Department of Anesthesiology of our hospital from June 2022 to April 2023, including 44 patients who received traditional anesthesia as the control group and 44 patients who received laryngeal mask airway sevoflurane general anesthesia as the observation group. Anesthesia and operation records of patients in the two groups were analyzed, including intraoperative vital signs, anesthesia induction time, recovery time of spontaneous breathing, first feeding time within 24 h after surgery, postoperative pain score, incidence of adverse reactions, Ramsay score and wake agitation, and other indicators were collected, and statistical analysis was conducted.

Results

The recovery time of the observation group was 7.88 ± 4.95 min, and the recovery time of spontaneous respiration was 10.58 ± 3.64 min, which were significantly shorter than 15.23 ± 5.12 min and 14.41 ± 3.56 min of the control group (P < 0.001). There were no significant differences between the two groups in anesthesia induction, operation duration and first feeding time within 24 h after operation (P > 0.05). There was no significant difference in postoperative pain scores between the two groups (P > 0.05). The overall incidence of adverse reactions was 6.82% in the observation group compared with 22.73% in the control group (χ² = 4.423, P = 0.035). In addition, the Ramsay score of the observation group was significantly improved compared with the control group (P < 0.05), and the incidence of agitation during the recovery period was also significantly decreased (P < 0.05).

Conclusion

Laryngeal mask airway sevoflurane anesthesia can significantly accelerate the recovery process of children after extraction of teeth, and reduce the occurrence of adverse reactions, providing a safer and more efficient choice than traditional anesthesia.

Unraveling the signaling network between dysregulated microRNA and mRNA expression in sevoflurane-induced developmental neurotoxicity in rat

Research has indicated that general anesthesia may cause neuroapoptosis and long-term cognitive dysfunction in developing animals, however, the precise mechanisms orchestrating these outcomes remain inadequately elucidated within scholarly discourse. The purpose of this study was to investigate the impact of sevoflurane on the hippocampus of developing rats by analyzing the changes in microRNA and mRNA and their interactions. Rats were exposed to sevoflurane for 4 h on their seventh day after birth, and the hippocampus was collected for analysis of neuroapoptosis by Western blot and immunohistochemistry. High-throughput sequencing was conducted to analyze the variances in miRNA and mRNA expression levels, and the Morris water maze was employed to assess long-term memory in rats exposed to sevoflurane after 8 weeks. The results showed that sevoflurane exposure led to dysregulation of 5 miRNAs and 306 mRNAs in the hippocampus. Bioinformatic analysis revealed that these dysregulated miRNA-mRNA target pairs were associated with pathological neurodevelopment and developmental disorders, such as regulation of axonogenesis, regulation of neuron projection development, regulation of neuron differentiation, transmission of nerve impulse, and neuronal cell body. Further analysis showed that these miRNAs formed potential network interactions with 44 mRNAs, and two important nodes were identified, miR-130b-5p and miR-449c-5p. Overall, this study suggests that the dysregulation of the miRNA-mRNA signaling network induced by sevoflurane may contribute to neurodevelopmental toxicity in the hippocampus of rats and be associated with long-term cognitive dysfunction.

Sevoflurane causes neurotoxicity and cognitive impairment by regulating Hippo signaling pathway-mediated ferroptosis via upregulating PRKCD

BACKGROUND

Sevoflurane (SEV) has been found to induce neurotoxicity and cognitive impairment, leading to the development of degenerative diseases. Protein kinase C delta (PRKCD) is upregulated in the hippocampus of SEV-treated mice and may be related to SEV-related neurotoxicity. However, the underlying molecular mechanisms by which SEV mediates neurotoxicity via PRKCD remain unclear.

METHODS

Normal mice and PRKCD knockout (KO) mice were exposed to SEV. Hippocampal neurons were isolated from mice hippocampal tissues. H&E staining was used for pathological morphology of hippocampal tissues, and NISSL staining was used to analyze the number of hippocampal neurons. The mRNA and protein levels were determined using quantitative real-time PCR, western blot, immunofluorescence staining and immunohistochemical staining. The mitochondrial microstructure was observed by transmission electron microscopy. Cell viability was detected by cell counting kit 8 assay, and ferroptosis was assessed by detecting related marker levels. The cognitive ability of mice was assessed by morris water maze test. And the protein levels of PRKCD, ferroptosis-related markers and Hippo pathway-related markers were examined by western bolt.

RESULTS

SEV increased PRKCD expression and ferroptosis in hippocampal tissues of mice. Also, SEV promoted mouse hippocampal neuron injury by inducing ferroptosis via upregulating PRKCD expression. Knockout of PRKCD alleviated SEV-induced neurotoxicity and cognitive impairment in mice, and relieved SEV-induced ferroptosis in hippocampal neurons. PRKCD could inhibit the activity of Hippo pathway, and its knockdown also overturned SEV-mediated ferroptosis by activating Hippo pathway.

CONCLUSION

SEV could induce neurotoxicity and cognitive impairment by promoting ferroptosis via inactivating Hippo pathway through increasing PRKCD expression.

Dexmedetomidine improves the circulatory dysfunction of the glymphatic system induced by sevoflurane through the PI3K/AKT/ΔFosB/AQP4 pathway in young mice

Multiple sevoflurane exposures may damage the developing brain. The neuroprotective function of dexmedetomidine has been widely confirmed in animal experiments and human studies. However, the effect of dexmedetomidine on the glymphatic system has not been clearly studied. We hypothesized that dexmedetomidine could alleviate sevoflurane-induced circulatory dysfunction of the glymphatic system in young mice. Six-day-old C57BL/6 mice were exposed to 3% sevoflurane for 2 h daily, continuously for 3 days. Intraperitoneal injection of either normal saline or dexmedetomidine was administered before every anaesthesia. Meanwhile the circulatory function of glymphatic system was detected by tracer injection at P8 and P32. On P30-P32, behavior tests including open field test, novel object recognition test, and Y-maze test were conducted. Primary astrocyte cultures were established and treated with the PI3K activator 740Y-P, dexmedetomidine, and small interfering RNA (siRNA) to silence ΔFosB. We propose for the first time that multiple exposure to sevoflurane induces circulatory dysfunction of the glymphatic system in young mice. Dexmedetomidine improves the circulatory capacity of the glymphatic system in young mice following repeated exposure to sevoflurane through the PI3K/AKT/ΔFosB/AQP4 signaling pathway, and enhances their long-term learning and working memory abilities.

The effect of N-acetylcysteine on the neurotoxicity of sevoflurane in developing hippocampus cells

Sevoflurane, a common pediatric anesthetic, has been linked to neurodegeneration, raising safety concerns. This study explored N-acetylcysteine's protective potential against sevoflurane-induced neurotoxicity in rat hippocampi. Four groups were examined: Control: Received 6 hours of 3 l/min gas (air and 30 % O2) and intraperitoneal saline. NAC: Received 6 hours of 3 l/min gas and 150 mg/kg NAC intraperitoneally. Sev: Exposed to 6 hours of 3 l/min gas and 3 % sevoflurane. Sev+NAC: Received 6 hours of 3 l/min gas, 3 % sevoflurane, and 150 mg/kg NAC. Protein levels of NRF-2, NLRP3, IL-1β, caspase-1, Beclin 1, p62, LC3A, and apoptosis markers were assessed. Sevoflurane and NAC alone reduced autophagy, while Sev+NAC group maintained autophagy levels. Sev group had elevated NRF-2, NLRP3, pNRF2, Caspase-1, and IL-1β, which were reduced in Sev+NAC. Apoptosis was higher in Sev, but Sev+NAC showed reduced apoptosis compared to the control. In summary, sevoflurane induced neurotoxicity in developing hippocampus, which was mitigated by N-acetylcysteine administration.

SHARPIN contributes to sevoflurane-induced neonatal neurotoxicity through up-regulating HMGB1 to repress M2 like-macrophage polarization

Sevoflurane exposure can result in neurotoxicity especially among children, which remains an important complication after surgery. However, its related mechanisms remain unclear. Here, we investigated the biological roles of SHARPIN in sevoflurane-induced neurotoxicity. As detected by qPCR, Western blotting and immunohistochemical staining, SHARPIN and HMGB1 expression was elevated in sevoflurane-stimulated mice as compared with the control mice. SHARPIN depletion attenuated hippocampus injury, repressed the expression of HMGB1 and M1-like macrophage markers (iNOS, TNF-α, IL-1β, IL-6), but enhanced the expression of M2-like macrophage markers (ARG-1, IL-10). GST pull-down and Co-IP assays demonstrated that SHARPIN directly interacted with HMGB1 to enhance HMGB1 expression in SH-SY5Y cells. The inhibitory effects of SHARPIN silencing on inflammatory reaction and M1-like macrophages were counteracted by HMGB1 overexpression. Finally, SHARPIN-HMGB1 pathway affected neuroinflammation triggered by sevoflurane via modulating macrophage polarization. Collectively, our data suggested that SHARPIN stimulated sevoflurane-induced neurotoxicity via converting M2-like macrophages to M1-like macrophages by enhancing HMGB1 expression. SHARPIN intervention may be a promising therapeutic method to relieve sevoflurane-induced neurotoxicity.

Efficacy of melatonin in alleviating disorders arising from repeated exposure to sevoflurane in males and females of the Wistar rats during preadolescence

Pediatricians use sevoflurane due to its fast action and short recovery time. However, studies have shown that repeated exposure to anesthesia can affect learning and memory. Melatonin, an indole-type neuroendocrine hormone, has significant anti-inflammatory, and neuroprotective properties. Melatonin's impact on cognitive behavior in sevoflurane-anesthetized males and females of the Wistar rats during preadolescence was examined in this research. The cognitive function was evaluated by shuttle box and morris water maze tests, while interleukin-10, Catalase (CAT), Malondialdehyde (MDA), and Tumor Necrosis Factor-α (TNF-α) were evaluated using ELISA kits. The expression levels of the apoptosis-linked proteins, Bax, Bcl-2, and caspase-3, were determined using the western blotting technique. The learning and memory latencies of the rats were more significant in the sevoflurane groups than in the control group; however, the latencies were significantly shorter in the sevoflurane and melatonin groups than in the control group. The levels of MDA, TNF-α, Bax, and caspase-3 were significantly higher in the sevoflurane groups than in the control group. We also found that the levels of CAT and Bcl-2 were significantly reduced in the sevoflurane groups compared to the control group. Increasing levels of CAT, Bcl-2, and decreasing levels of MDA, TNF-α, Bax, and caspase-3 in response to melatonin indicate a possible contribution to the recovery from the sevoflurane impairment. Melatonin shows neuroprotective effects in male and female rats with sevoflurane-induced cognitive impairment. This suggests melatonin could be a valuable treatment for learning and memory deficits resulting from repeated exposure to sevoflurane, possibly by controlling apoptosis, oxidative stress, and inflammation.

The changing of α5-GABAA receptors expression and distribution participate in sevoflurane-induced learning and memory impairment in young mice

BACKGROUND

Sevoflurane is a superior agent for maintaining anesthesia during surgical procedures. However, the neurotoxic mechanisms of clinical concentration remain poorly understood. Sevoflurane can interfere with the normal function of neurons and synapses and impair cognitive function by acting on α5-GABAAR.

METHODS

Using MWM test, we evaluated cognitive abilities in mice following 1 h of anesthesia with 2.7%-3% sevoflurane. Based on hippocampal transcriptome analysis, we analyzed the differential genes and IL-6 24 h post-anesthesia. Western blot and RT-PCR were performed to measure the levels of α5-GABAAR, Radixin, P-ERM, P-Radixin, Gephyrin, IL-6, and ROCK. The spatial distribution and expression of α5-GABAAR on neuronal somata were analyzed using histological and three-dimensional imaging techniques.

RESULTS

MWM test indicated that partial long-term learning and memory impairment. Combining molecular biology and histological analysis, our studies have demonstrated that sevoflurane induces immunosuppression, characterized by reduced IL-6 expression levels, and that enhanced Radixin dephosphorylation undermines the microstructural stability of α5-GABAAR, leading to its dissociation from synaptic exterior and resulting in a disordered distribution in α5-GABAAR expression within neuronal cell bodies. On the synaptic cleft, the expression level of α5-GABAAR remained unchanged, the spatial distribution became more compact, with an increased fluorescence intensity per voxel. On the extra-synaptic space, the expression level of α5-GABAAR decreased within unchanged spatial distribution, accompanied by an increased fluorescence intensity per voxel.

CONCLUSION

Dysregulated α5-GABAAR expression and distribution contributes to sevoflurane-induced partial long-term learning and memory impairment, which lays the foundation for elucidating the underlying mechanisms in future studies.

Modern Radiation Treatment Planning Parameters and Outcomes in Pediatric Tectal Gliomas

Purpose

Pediatric low-grade tectal gliomas are rare, indolent tumors of the brain stem. We reviewed outcomes of pediatric patients who received a diagnosis of low-grade tectal gliomas and report dosimetric parameters for those receiving radiation therapy (RT).

Methods and Materials

We retrospectively reviewed all pediatric patients (age <18 years) at our institution diagnosed with a low-grade glioma between 1993 and 2020 (n = 288). Twenty-three patients with tectal gliomas were identified. Patients who received RT (n = 8) had detailed dosimetric analyses performed. Doses to critical structures and any resulting toxicities were reviewed. Minimum follow-up was 2 years and complete follow-up was available for all patients.

Results

Twenty-three patients, with a median age of 8.9 years, were included (range, 0.5-16.2 years). At a median follow-up of 7.4 years (range, 2-24 years), all were alive at the end of the study period. Three patients (13%) were treated with upfront RT; none of these patients developed local failure (LF) after a median follow-up of 10.6 years. One patient was treated with upfront chemotherapy with no evidence of progression afterward. Nineteen patients were initially observed after diagnosis and 26% of them (n = 5) experienced local progression. All 5 were treated with salvage RT, with 1 patient requiring further treatment with chemotherapy. Fractionation schedules for patients undergoing upfront or salvage RT included 50.4 Gy in 28 fractions (n = 4), 54 Gy in 30 fractions (n = 2), and 51 Gy in 30 fractions (n = 2). For patients treated after 2007, the gross tumor volume was delineated on a T2 magnetic resonance imaging with an average gross tumor volume-to-planning target volume expansion of 4.5 mm (range, 3-5 mm). Detailed dosimetric parameters were available for all patients treated with RT.

Conclusions

Our review supports the indolent behavior for most tectal gliomas. For the subset of tumors with evidence of progression, modern photon RT results in excellent oncologic outcomes with minimal late effects.

7,8-Dihydroxyflavone ameliorates cognitive impairment induced by repeated neonatal sevoflurane exposures in mice through increasing tau O-GlcNAcylation

BACKGROUND

Sevoflurane, one of the most commonly used general anesthetics for pediatric anesthesia, has recently gained significant attention in both preclinical and clinical settings due to its potential neurotoxicity in the developing brain. Tau phosphorylation, induced by sevoflurane, is recognized as one of the major causes of neurotoxicity. 7,8-dihydroxyflavone (DHF), a TrkB receptor agonist, has been reported to exhibit potential neuroprotective effects against tauopathies. In this study, our objective was to investigate whether DHF could provide neuroprotective effects against sevoflurane-induced neurotoxicity and explore the underlying molecular mechanisms.

METHODS

Six-day-old mice were subjected to 2 h of anesthesia with 3 % sevoflurane, with or without pretreatment of DHF (5 mg/kg/day, i.p.) for 3 consecutive days. Autonomic motor ability was assessed by open-field test, while learning and memory abilities were evaluated by the fear conditioning test. Western blotting was conducted to measure the levels of t-TrkB, p-TrkB, tau, and phosphorylated tau. Additionally, a co-immunoprecipitation assay was performed to investigate the interaction between O-GlcNAcylation and tau.

RESULTS

Repeated neonatal sevoflurane exposures resulted in reduced freezing time during the context and cued fear conditioning tests in adulthood. However, pretreatment with DHF restored the freezing time to the level of the control group, indicating that DHF effectively alleviated cognitive impairments induced by neonatal sevoflurane exposure. We also observed that repeated neonatal sevoflurane exposures increased tau phosphorylation while decreasing tau O-GlcNAcylation. However, DHF pretreatment rebalanced the tau O-GlcNAcylation/phosphorylation ratio by enhancing the interaction between tau and O-GlcNAcylation.

CONCLUSION

Our findings demonstrate that DHF effectively ameliorates sevoflurane-induced cognitive impairment in developing mice by restoring the balance between tau O-GlcNAcylation and phosphorylation. Therefore, this study suggests that DHF has the potential to be a therapeutic agent for treating cognitive impairment associated with anesthetics, such as sevoflurane.

Electroacupuncture Pretreatment Attenuates Learning Memory Impairment Induced by Repeated Propofol Exposure and Modulates Hippocampal Synaptic Plasticity in Rats

Background

Recurrent propofol anesthesia in the peak of neurodevelopment may lead to learning-memory decline. This study aimed to examine the efficacy of electroacupuncture pretreatment in ameliorating the aforementioned learning memory deficits and to explore its underlying mechanisms in a rat model of repeated propofol exposure.

Methods

10-day-old Sprague Dawley rats were randomly assigned to five groups: the control, fat emulsion, propofol, electroacupuncture pretreatment and electroacupuncture pretreatment combined with propofol groups. The electroacupuncture pretreatment involved three consecutive daily sessions, while propofol was received intraperitoneally once daily for five days. Following the modeling period, the rats' learning-memory performance was assessed using the New Novel Arm Y-maze, New Object Recognition, and Morris Water Maze. The Nissl staining method was used to observe the development of hippocampal neurons, while Golgi staining was employed to observe hippocampal synaptic development.

Results

The electroacupuncture pretreatment significantly attenuated the learning and memory impairment induced by recurring propofol exposure in rats. Additionally, it facilitated the development of hippocampal neurons and synaptic plasticity in the hippocampus. Immunofluorescence and Western Blot analyses were conducted to detect the expression of proteins related to apoptosis, learning memory, and synaptic plasticity. In the propofol group, the pro-apoptotic factors Caspase-3 and Bax was up-regulated, while the anti-apoptotic factor Bcl-2 was down-regulated, as compared to the blank group. Additionally, the phosphorylated cAMP-response element binding protein (pCREB), brain-derived neurotrophic factor (BDNF), synaptophysin, and growth associated protein-43 (GAP-43) was significantly decreased. In contrast, the electroacupuncture pretreatment combined with propofol group exhibited decreased the Caspase-3 and Bax and increased the Bcl-2, as compared to the propofol group, meanwhile, the pCREB, BDNF, Synaptophysin and GAP-43 was increased.

Conclusion

Our findings indicate that electroacupuncture pretreatment can alleviate the learning and memory impairment induced by recurring propofol exposure in rats. This is achieved by enhancing hippocampal synaptic plasticity, activating the pCREB/BDNF pathway and inhibiting neuronal apoptosis.

Brain injury and long-term outcome after neonatal surgery for non-cardiac congenital anomalies

BACKGROUND

There is growing evidence that neonatal surgery for non-cardiac congenital anomalies (NCCAs) in the neonatal period adversely affects long-term neurodevelopmental outcome. However, less is known about acquired brain injury after surgery for NCCA and abnormal brain maturation leading to these impairments.

METHODS

A systematic search was performed in PubMed, Embase, and The Cochrane Library on May 6, 2022 on brain injury and maturation abnormalities seen on magnetic resonance imaging (MRI) and its associations with neurodevelopment in neonates undergoing NCCA surgery the first month postpartum. Rayyan was used for article screening and ROBINS-I for risk of bias assessment. Data on the studies, infants, surgery, MRI, and outcome were extracted.

RESULTS

Three eligible studies were included, reporting 197 infants. Brain injury was found in n = 120 (50%) patients after NCCA surgery. Sixty (30%) were diagnosed with white matter injury. Cortical folding was delayed in the majority of cases. Brain injury and delayed brain maturation was associated with a decrease in neurodevelopmental outcome at 2 years of age.

CONCLUSIONS

Surgery for NCCA was associated with high risk of brain injury and delay in maturation leading to delay in neurocognitive and motor development. However, more research is recommended for strong conclusions in this group of patients.

IMPACT

Brain injury was found in 50% of neonates who underwent NCCA surgery. NCCA surgery is associated with a delay in cortical folding. There is an important research gap regarding perioperative brain injury and NCCA surgery.

Impact of propofol versus sevoflurane anesthesia on molecular subtypes and immune checkpoints of glioma during surgery

Background

Sevoflurane and propofol are two popular anesthetics used during glioblastoma (GBM) surgery. This investigation compared the molecular subtypes and immune checkpoints of cancer cells following GBM surgery under sevoflurane and propofol anesthesia.

Method

The expression profile data and clinical information of glioma samples of different grades were downloaded from The Cancer Genome Atlas database. Weighted gene coexpression network analysis was used to identify hub modules and key genes related to glioma grades (G2 and G3). The GEO database (GSE179004) was used to retrieve glioma surgical specimens with different anesthetic gene expression profiles. The differential expression of immune checkpoint genes under various anesthetic settings was examined using the R-ggplot2.

Results

Compared to sevoflurane, propofol significantly downregulated SERPINI1 and CAMK2A expression. These are also important factors in glioma grading. Simultaneously, SERPINI1 and CAMK2A were also significantly related to the prognosis of GBM and lower-grade glioma patients and acted as potential tumor suppressors. In addition, propofol increases the expression of the immune checkpoint molecule, PD-L1.

Conclusions

Our study revealed that sevoflurane can more effectively prevent the development of glioma after surgery than propofol, and SERPINI1 can be used as a new independent prognostic factor for glioma.

Multiple General Anesthesia in Children: A Systematic Review of Its Effect on Neurodevelopment

The effect of multiple general anesthesia (mGA) procedures administered in early life is a critical theme and has led the Food and Drug Administration (FDA) to issue an alert. This systematic review seeks to explore the potential effects on neurodevelopment of mGA on patients under 4 years. The Medline, Embase and Web of Science databases were searched for publications up to 31 March 2021. The databases were searched for publications regarding "children multiple general anesthesia OR pediatric multiple general anesthesia". Case reports, animal studies and expert opinions were excluded. Systematic reviews were not included, but they were screened to identify any possible additional information. A total of 3156 studies were identified. After removing the duplicates, screening the remaining records and analyzing the systematic reviews' bibliography, 10 studies were considered suitable for inclusion. Comprehensively, a total cohort of 264.759 unexposed children and 11.027 exposed children were assessed for neurodevelopmental outcomes. Only one paper did not find any statistically significant difference between exposed and unexposed children in terms of neurodevelopmental alterations. Controlled studies on mGA administered before 4 years of age support that there might be a greater risk of neurodevelopmental delay in children receiving mGA, warranting the need for careful risk/benefit considerations.

Calpain-TRPC6 signaling pathway contributes to propofol-induced developmental neurotoxicity in rats

Growing animal studies suggest a risk of neuronal damage following early childhood exposure to anesthesia and sedation drugs including propofol. Inhibition of transient receptor potential canonical 6 (TRPC6) degradation has been shown to protect neurons from neuronal damage induced by multiple brain injury models. Our aim was to investigate whether calpain-TRPC6 pathway is a target in propofol-induced neurotoxicity. Postnatal day (PND) 7 rats were exposed to five bolus injections of 25 mg/kg propofol or 10 % intralipid at hourly intervals. Neuronal injury was assessed by the expression pattern of TUNEL staining and cleaved-caspase-3. The Morris water maze test was used to evaluate learning and memory functions in later life. Pretreatments consisting of intracerebroventricular injections of a TRPC6 agonist, TRPC6 inhibitor, or calpain inhibitor were used to confirm the potential role of the calpain-TRPC6 pathway in propofol-induced neurotoxicity. Prolonged exposure to propofol induced neuronal injury, downregulation of TRPC6, and enhancement of calpain activity in the cerebral cortex up to 24 h after anesthesia. It also induced long-term behavioral disorders, manifesting as longer escape latency at PND40 and PND41 and as fewer platform-crossing times and less time spent in the target quadrant at PND42. These propofol-induced effects were attenuated by treatment with the TRPC6 agonist and exaggerated by the TRPC6 inhibitor. Pretreatment with the calpain inhibitor alleviated the propofol-induced TRPC6 downregulation and neuronal injury in the cerebral cortex. In conclusion, our data suggest that a calpain-TRPC6 signaling pathway contributes to propofol-induced acute cortical neuron injury and long-term behavioral disorders in rats.

Consequences of General Anesthesia in Infancy on Behavior and Brain Structure

BACKGROUND

One in 7 children will need general anesthesia (GA) before the age of 3. Brain toxicity of anesthetics is controversial. Our objective was to clarify whether exposure of GA to the developing brain could lead to lasting behavioral and structural brain changes.

METHODS

A first study was performed in mice. The behaviors (fear conditioning, Y-maze, and actimetry) and brain anatomy (high-resolution magnetic resonance imaging) of 6- to 8-week-old Swiss mice exposed or not exposed to GA from 4 to 10 days old were evaluated. A second study was a complementary analysis from the preexisting APprentissages EXécutifs et cerveau chez les enfants d'âge scolaire (APEX) cohort to assess the replicability of our data in humans. The behaviors (behavior rating inventory of executive function, emotional control, and working memory score, Backward Digit Span, and Raven 36) and brain anatomy (high-resolution magnetic resonance imaging) were compared in 102 children 9 to 10 years of age exposed or not exposed to a single GA (surgery) during infancy.

RESULTS

The animal study revealed chronic exacerbated fear behavior in the adult mice (95% confidence interval [CI], 4-80; P = .03) exposed to postnatal GA; this was associated with an 11% (95% CI, 7.5-14.5) reduction of the periaqueductal gray matter (P = .046). The study in humans suggested lower emotional control (95% CI, 0.33-9.10; P = .06) and a 6.1% (95% CI, 4.3-7.8) reduction in the posterior part of the right inferior frontal gyrus (P = .019) in the children who had been exposed to a single GA procedure.

CONCLUSIONS

The preclinical and clinical findings of these independent studies suggest lasting effects of early life exposure to anesthetics on later emotional control behaviors and brain structures.

Sevoflurane participates in the protection of rat renal ischemia-reperfusion injury by down-regulating the expression of TRPM7

INTRODUCTION

To investigate the protective effect of sevoflurane preconditioning on renal ischemia-reperfusion injury (renalischemiareperfusionmodel, RIRI) and its related mechanism.

METHODS

Eighty healthy adult male SD rats were randomly divided into control group (Sham group), model group (RIRI group), sevoflurane pretreatment group (Sev group) and TRPM7 inhibitor combined with sevoflurane pretreatment group (T + Sev group), 20 animals in each group. Hematoxylin-eosin (HE) staining was used to observe the pathological changes of renal tissue, and the levels of creatinine and urea nitrogen in each group were detected. Deoxyribonucleic acid terminal transferase-mediated dUTP nick end labeling (TUNEL) assay was used to detect renal cell apoptosis, and Western blottingwas used to detect the expression of apoptotic proteins cleaved-caspase-3, bax, Bcl-2, and TRPM7 in renal tissue; Detection of oxidative stress-related index levels in renal tissue and levels of inflammatory factors in renal tissue and serum.

RESULTS

Compared with the Sham group, the renal tissue pathological damage was aggravated, the levels of creatinine and blood urea nitrogen were increased, and the apoptosis was increased in the RIR group and the Sev group. Death, malondialdehyde (MDA) levels and inflammatory factors were increased, and superoxide dismutase (SOD) levels were decreased (all p < .05); The scores, apoptosis rate, MDA level, and relative expression of inflammatory factor levels were decreased, and SOD levels were increased (all p < .05). Compared with the Sev group, the renal tissue pathological damage in the T + Sev group was aggravated, creatinine, blood urea nitrogen levels increased, apoptosis increased, apoptosis-related proteins cleaved-caspase-3, bax, Bcl-2 showed increased apoptosis, malondialdehyde (MDA) levels, inflammatory factor levels increased, ultrahigh The levels of oxide dismutase (SOD) were decreased (all p < .05).

CONCLUSIONS

Therefore, we believe that sevoflurane is involved in the protection of rat renal ischemia-reperfusion injury by downregulating the expression of TRPM7.

Echinatin mitigates sevoflurane-induced hippocampal neurotoxicity and cognitive deficits through mitigation of iron overload and oxidative stress

CONTEXT

Sevoflurane (Sev) is a commonly used surgical anaesthetic; it has neurotoxic effects on the brain. Echinatin (Ech) is reported to have anti-inflammatory and antioxidant activity.

OBJECTIVE

This research confirms the effect of Ech on Sev-induced neurotoxicity and cognitive deficits.

MATERIALS AND METHODS

Primary rat hippocampal neurons were treated with 4.1% Sev for 6 h in the presence of Ech (5, 10, and 20 μM) or vehicle, followed by a further 42 h of culture. Male Sprague-Dawley aged rats were divided into 6 groups (n = 6): control, Sev, Sev + Ech (20 mg/kg;), Sev + Ech (40 mg/kg), and Sev + Ech (80 mg/kg). Rats were intraperitoneally injected with Ech or vehicle 1 h before Sev exposure (2% Sev for 5 h).

RESULTS

We found that Ech (5, 10, and 20 μM) elevated cell viability (1.29-, 1.51-, 1.68-fold) but mitigated apoptosis (23.87% vs. 16.48%, 12.72%, 9.02%), oxidative stress, and ferroptosis in hippocampal neurons with Sev treatment. Ech activated the Nrf2 expression in Sev-induced in vitro and in vivo models of anaesthetic neurotoxicity. Ech also weakened neurotoxicity in hippocampal neurons with Sev treatment by increasing Nrf2 expression level. Moreover, Ech alleviated hippocampus neurons apoptosis (19.38% vs. 16.05%, 11.71%, 8.88%), oxidative stress, and ferroptosis in rats with Sev treatment. Ech improved Sev-induced cognitive deficits in rats.

CONCLUSIONS

Ech alleviates Sev-induced neurotoxicity and cognitive deficits by mitigation of ferroptosis and oxidative stress. Ech may be developed as a new promising therapeutic drug for treatment of cerebral nerve injury caused by surgical anaesthesia.

Lin28A Reduced Sevoflurane-Induced Nerve Injury and Cognitive Dysfunction by Inhibiting Tau Acetylation and Phosphorylation via Activating SIRT1 in Elderly Rats

Sevoflurane (Sev) might cause neurotoxicity in elderly rats. However, the role of Lin28A in Sev-induced neurotoxicity remains unclear in elderly rats. In this study, elderly rats were used to construct an Sev-induced nerve injury model. Learning and memory abilities were assessed by Morris water maze (MWM) trainings; pathological alterations in hippocampal region were assessed by HE staining; neuronal apoptosis was assessed by TUNEL; related protein expression was analyzed by immunofluorescence, immunohistochemistry, and Western blotting. Results of this study showed that Sev treatment caused nerve injury and cognitive dysfunction in elderly rats, with increased neuronal apoptosis and decreased Lin28A levels. Pathological impairment and learning and memory abilities of elderly rats were significantly improved after forced overexpression of Lin28A using AAV, accompanied by decreased expression of CD68, Iba-1, and GFAP. TUNEL analysis showed that Lin28A overexpression significantly reversed Sev-induced neuronal apoptosis. Further mechanistic analysis showed that Lin28A significantly promoted SIRT1 expression, which further reversed Sev-induced Tau acetylation at lysine 280 and 686 and Tau hyperphosphorylation, thereby alleviating nerve injury and cognitive dysfunction in elderly rats. The introduction of SIRT1 inhibitor EX527 further confirmed the involvement of SIRT1 in the regulation of Lin28A in elderly rats. In conclusion, our findings demonstrated that Lin28A reduced sevoflurane-induced nerve injury and cognitive dysfunction by inhibiting Tau acetylation and phosphorylation via activating SIRT1 in elderly rats.

L-cysteine methyl ester overcomes the deleterious effects of morphine on ventilatory parameters and arterial blood-gas chemistry in unanesthetized rats

We are developing a series of thiolesters that produce an immediate and sustained reversal of the deleterious effects of opioids, such as morphine and fentanyl, on ventilation without diminishing the antinociceptive effects of these opioids. We report here the effects of systemic injections of L-cysteine methyl ester (L-CYSme) on morphine-induced changes in ventilatory parameters, arterial-blood gas (ABG) chemistry (pH, pCO₂, pO₂, sO₂), Alveolar-arterial (A-a) gradient (i.e., the index of alveolar gas-exchange within the lungs), and antinociception in unanesthetized Sprague Dawley rats. The administration of morphine (10 mg/kg, IV) produced a series of deleterious effects on ventilatory parameters, including sustained decreases in tidal volume, minute ventilation, inspiratory drive and peak inspiratory flow that were accompanied by a sustained increase in end inspiratory pause. A single injection of L-CYSme (500 μmol/kg, IV) produced a rapid and long-lasting reversal of the deleterious effects of morphine on ventilatory parameters, and a second injection of L-CYSme (500 μmol/kg, IV) elicited pronounced increases in ventilatory parameters, such as minute ventilation, to values well above pre-morphine levels. L-CYSme (250 or 500 μmol/kg, IV) also produced an immediate and sustained reversal of the deleterious effects of morphine (10 mg/kg, IV) on arterial blood pH, pCO₂, pO₂, sO₂ and A-a gradient, whereas L-cysteine (500 μmol/kg, IV) itself was inactive. L-CYSme (500 μmol/kg, IV) did not appear to modulate the sedative effects of morphine as measured by righting reflex times, but did diminish the duration, however, not the magnitude of the antinociceptive actions of morphine (5 or 10 mg/kg, IV) as determined in tail-flick latency and hindpaw-withdrawal latency assays. These findings provide evidence that L-CYSme can powerfully overcome the deleterious effects of morphine on breathing and gas-exchange in Sprague Dawley rats while not affecting the sedative or early stage antinociceptive effects of the opioid. The mechanisms by which L-CYSme interferes with the OR-induced signaling pathways that mediate the deleterious effects of morphine on ventilatory performance, and by which L-CYSme diminishes the late stage antinociceptive action of morphine remain to be determined.

S-ketamine administration in pregnant mice induces ADHD- and depression-like behaviors in offspring mice

BACKGROUND

Anesthesia and psychotropic drugs in pregnant women may cause long-term effects on the brain development of unborn babies. The authors set out to investigate the neurotoxicity of S-ketamine, which possesses anesthetic and antidepressant effects and may cause attention deficit hyperactivity disorder (ADHD)- and depression-like behaviors in offspring mice.

METHODS

Pregnant mice were administered with low-, medium-, and high-dose S-ketamine (15, 30, and 60 mg/kg) by intraperitoneal injection for 5 days from gestational day 14-18. At 21 days after birth, an elevated plus-maze test, fear conditioning, open field test, and forced swimming test were used to assess ADHD- and depression-like behaviors. Neuronal amount, glial activation, synaptic function indicated by ki67, and inhibitory presynaptic proteins revealed by GAD2 in the hippocampus, amygdala, habenula nucleus, and lateral hypothalamus (LHA) were determined by immunofluorescence assay.

RESULTS

All the pregnant mice exposed to high-dose S-ketamine administration had miscarriage after the first injection. Both low-dose and medium-dose S-ketamine administration significantly increased the open-arm time and attenuated frozen time in the fear conditioning, which indicates impulsivity and memory dysfunction-like behaviors. Medium-dose S-ketamine administration reduced locomotor activity in the open field and increased immobility time in the forced swimming test, indicating depression-like behaviors. Changes in astrocytic activation, synaptic dysfunction, and decreased inhibitory presynaptic proteins were found in the hippocampus, amygdala, and habenula nucleus.

CONCLUSIONS

These results demonstrate that S-ketamine may lead to detrimental effects, including ADHD-and depression-like behaviors in offspring mice. More studies should be promoted to determine the neurotoxicity of S-ketamine in the developing brain.