Propofol, but not etomidate, increases corticosterone levels and induces long-term alteration in hippocampal synaptic activity in neonatal rats. Neurosci Lett. 2016;618:1-5. [PMID: 26923669 DOI: 10.1016/j.neulet.2016.02.045]

Intergenerational Perioperative Neurocognitive Disorder

Accelerated neurocognitive decline after general anesthesia/surgery, also known as perioperative neurocognitive disorder (PND), is a widely recognized public health problem that may affect millions of patients each year. Advanced age, with its increasing prevalence of heightened stress, inflammation, and neurodegenerative alterations, is a consistent contributing factor to the development of PND. Although a strong homeostatic reserve in young adults makes them more resilient to PND, animal data suggest that young adults with pathophysiological conditions characterized by excessive stress and inflammation may be vulnerable to PND, and this altered phenotype may be passed to future offspring (intergenerational PND). The purpose of this narrative review of data in the literature and the authors' own experimental findings in rodents is to draw attention to the possibility of intergenerational PND, a new phenomenon which, if confirmed in humans, may unravel a big new population that may be affected by parental PND. In particular, we discuss the roles of stress, inflammation, and epigenetic alterations in the development of PND. We also discuss experimental findings that demonstrate the effects of surgery, traumatic brain injury, and the general anesthetic sevoflurane that interact to induce persistent dysregulation of the stress response system, inflammation markers, and behavior in young adult male rats and in their future offspring who have neither trauma nor anesthetic exposure (i.e., an animal model of intergenerational PND).

Sevoflurane Exposure in the Developing Brain Induces Hyperactivity, Anxiety-Free, and Enhancement of Memory Consolidation in Mice

Background

Sevoflurane exposure at brain developmental stages has been reported to induce neurotoxicity and, subsequently, results in learning deficits at the juvenile age. In this study, we aimed to investigate the effects of prior early-age sevoflurane exposure on locomotor activity, anxiety, CA1-dependent learning, and spatial memory, as well as synapse changes in mice.

Methods

Totally, 3% sevoflurane was given to neonatal mice at postnatal day 7 for 4 h. These sevoflurane-treated mice were later subjected to open field and Morris water maze tests at their adult age (postnatal days 60–90) to assess their motor activity and spatial learning ability, respectively. The brain slices of sevoflurane-treated and control mice were examined for dendritic spine density and long-term potentiation (LTP) features following behavior tests (postnatal day 60). Protein levels of N-methyl-D-aspartate (NMDA) receptor subtypes and PSD95 in brain lysate were measured by using immunoblotting at the same age (postnatal day 60).

Results

Prior early-age sevoflurane exposure increased the overall moving distance, prolonged the central-area lingering time, and increased the central-area entries of adult mice. Sevoflurane-treated mice spent more time in the target quadrant during the probe test. An increase of the spine density of pyramidal neurons in the CA1 region was observed in sevoflurane-treated mice. NMDA receptor GluN2A subunit, but not the GluN2B or PSD95, was increased in the brain lysate of sevoflurane-treated mice compared with that of control mice. LTP in the hippocampus did not significantly differ between sevoflurane-treated and control mice.

Conclusion

Exposure to sevoflurane for mice during an early brain developmental stage (P7) induces later-on hyperactivity, anxiety-free, and enhancement of memory retention. These observations shed light on future investigations on the underlying mechanisms of sevoflurane’s effect on neuronal development.

Changes of inflammatory factors in patients after resection of lung adenocarcinoma with propofol and etomidate

OBJECTIVE

This research was designed to investigate the changes of inflammatory factors in patients after resection of lung adenocarcinoma with propofol versus etomidate.

METHODS

A total of 104 patients who underwent resection of lung adenocarcinoma in our hospital were divided into a propofol group (group A, n=50) and an etomidate group (group B, n=54). The levels of CRP and IL-6 at different time points and the changes of blood gas indexes at 10 min before and after operation were observed in both groups. Their pain score and quality of life score were compared. Besides, we observed the wake-up time, tracheal extubation time and the incidence of adverse reactions.

RESULTS

The anesthesia recovery and tracheal extubation time in group B were shorter than those in group A (P<0.05). After 10-minutes of spontaneous breathing, PaO₂ and SaO₂ in group B were higher than those in group A (P<0.05), and PaCO₂ was lower (P<0.05); compared with group A. The incidence of adverse reactions and the levels of inflammatory factors in group B were lower than those in group A after operation (both P<0.05). The quality of life of patients in group B after operation was better than that in group A (P<0.05). There was no marked difference in VAS scores between groups.

CONCLUSION

Etomidate has better anesthetic effect than propofol in lung adenocarcinoma resection, leading to better stabilization of the vital signs of patients and it also has higher safety.

RTA-408 protects against propofol-induced cognitive impairment in neonatal mice via the activation of Nrf2 and the inhibition of NF-κB p65 nuclear translocation

OBJECTIVE

To explore the effect of RTA-408 on the propofol-induced cognitive impairment of neonatal mice via regulating Nrf2 and NF-κB p65 nuclear translocation.

METHODS

C57BL/6 neonatal mice were randomized into intralipid, propofol, vehicle + propofol, and RTA-408 + propofol groups. The learning and memory ability was inspected by Morries water maze (MWM) test. TUNEL staining was performed to examine the apoptosis of neurons in hippocampus. The gene and protein expressions in hippocampus were detected by immunohistochemistry, qRT-PCR, or Western blotting. The activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were tested by the corresponding kits.

RESULTS

Propofol prolonged escape latency of mice, decreased the times of crossing the platform, and shortened the time of staying in the target quadrant, while RTA-408 treatment improved the above-mentioned situation. Besides, Nrf2 protein in hippocampus of mice induced by propofol was decreased with the increased NF-κB p65 nuclear translocation, which was reversed by RTA-408. Meanwhile, RTA-408 decreased the apoptosis of neurons accompanying with the down-regulation of Caspase-3 and the up-regulations of neuronal-specific nuclear protein (NeuN), microtubule-associated protein 2 (Map2), Ca₂⁺ /Calmodulin-dependent Protein Kinase II (CaMKII), and parvalbumin (PV) immunostaining in hippocampus. Besides, propofol-induced high levels of proinflammatory cytokines and antioxidase activities in hippocampus were reduced by RTA-408.

CONCLUSION

RTA-408 improved propofol-induced cognitive impairment in neonatal mice via enhancing survival of neurons, reducing the apoptosis of hippocampal neurons, mitigating the inflammation and oxidative stress, which may be correlated with the activation of Nrf2 and the inhibition of NF-κB p65 nuclear translocation.

Nonexperimental Xenobiotics: Unintended Consequences of Intentionally Administered Substances in Terrestrial Animal Models

Review of the use of nonexperimental xenobiotics in terrestrial animal models and the potential unintended consequences of these compounds, including drug-related side effects and adverse reactions.

Neuroendocrine, epigenetic, and intergenerational effects of general anesthetics

The progress of modern medicine would be impossible without the use of general anesthetics (GAs). Despite advancements in refining anesthesia approaches, the effects of GAs are not fully reversible upon GA withdrawal. Neurocognitive deficiencies attributed to GA exposure may persist in neonates or endure for weeks to years in the elderly. Human studies on the mechanisms of the long-term adverse effects of GAs are needed to improve the safety of general anesthesia but they are hampered not only by ethical limitations specific to human research, but also by a lack of specific biological markers that can be used in human studies to safely and objectively study such effects. The latter can primarily be attributed to an insufficient understanding of the full range of the biological effects induced by GAs and the molecular mechanisms mediating such effects even in rodents, which are far more extensively studied than any other species. Our most recent experimental findings in rodents suggest that GAs may adversely affect many more people than is currently anticipated. Specifically, we have shown that anesthesia with the commonly used GA sevoflurane induces in exposed animals not only neuroendocrine abnormalities (somatic effects), but also epigenetic reprogramming of germ cells (germ cell effects). The latter may pass the neurobehavioral effects of parental sevoflurane exposure to the offspring, who may be affected even at levels of anesthesia that are not harmful to the exposed parents. The large number of patients who require general anesthesia, the even larger number of their future unexposed offspring whose health may be affected, and a growing number of neurodevelopmental disorders of unknown etiology underscore the translational importance of investigating the intergenerational effects of GAs. In this mini review, we discuss emerging experimental findings on neuroendocrine, epigenetic, and intergenerational effects of GAs.

Neonatal phenobarbital exposure disrupts GABAergic synaptic maturation in rat CA1 neurons

OBJECTIVE

Phenobarbital is the most commonly utilized drug for the treatment of neonatal seizures. The use of phenobarbital continues despite growing evidence that it exerts suboptimal seizure control and is associated with long-term alterations in brain structure, function, and behavior. Alterations following neonatal phenobarbital exposure include acute induction of neuronal apoptosis, disruption of synaptic development in the striatum, and a host of behavioral deficits. These behavioral deficits include those in learning and memory mediated by the hippocampus. However, the synaptic changes caused by acute exposure to phenobarbital that lead to lasting effects on brain function and behavior remain understudied.

METHODS

Postnatal day (P)7 rat pups were treated with phenobarbital (75 mg/kg) or saline. On P13-14 or P29-37, acute slices were prepared and whole-cell patch-clamp recordings were made from CA1 pyramidal neurons.

RESULTS

At P14 we found an increase in miniature inhibitory postsynaptic current (mIPSC) frequency in the phenobarbital-exposed as compared to the saline-exposed group. In addition to this change in mIPSC frequency, the phenobarbital group displayed larger bicuculline-sensitive tonic currents, decreased capacitance and membrane time constant, and a surprising persistence of giant depolarizing potentials. At P29+, the frequency of mIPSCs in the saline-exposed group had increased significantly from the frequency at P14, typical of normal synaptic development; at this age the phenobarbital-exposed group displayed a lower mIPSC frequency than did the control group. Spontaneous inhibitory postsynaptic current (sIPSC) frequency was unaffected at either P14 or P29+.

SIGNIFICANCE

These neurophysiological alterations following phenobarbital exposure provide a potential mechanism by which acute phenobarbital exposure can have a long-lasting impact on brain development and behavior.