Clinical researches including the Mayo Anesthesia Safety in Kids (MASK) study have found that children undergoing multiple anesthesia may have a higher risk of fine motor control difficulties. However, the underlying mechanisms remain elusive. Here, we report that erythropoietin receptor (EPOR), a microglial receptor associated with phagocytic activity, was significantly downregulated in the medial prefrontal cortex of young mice after multiple sevoflurane anesthesia exposure. Importantly, we found that the inhibited erythropoietin (EPO)/EPOR signaling axis led to microglial polarization, excessive excitatory synaptic pruning, and abnormal fine motor control skills in mice with multiple anesthesia exposure, and those above-mentioned situations were fully reversed by supplementing EPO-derived peptide ARA290 by intraperitoneal injection. Together, the microglial EPOR was identified as a key mediator regulating early synaptic development in this study, which impacted sevoflurane-induced fine motor dysfunction. Moreover, ARA290 might serve as a new treatment against neurotoxicity induced by general anesthesia in clinical practice by targeting the EPO/EPOR signaling pathway.
Animals ; Sevoflurane/toxicity* ; Microglia/drug effects* ; Anesthetics, Inhalation/adverse effects* ; Mice ; Mice, Inbred C57BL ; Receptors, Erythropoietin/metabolism* ; Neuronal Plasticity/drug effects* ; Male ; Prefrontal Cortex/drug effects* ; Erythropoietin/pharmacology* ; Signal Transduction/drug effects*

To investigate the effect of SB203580, a p38MAPK specific inhibitor, on ropivacaine-induced cytotoxicity in PC12 cells.
 Methods: PC12 cells were divided into three groups: the normal group (Group N), cells were cultured for 48 h; the ropivacaine group (Group R), cells were cultured with 15 mmol/L ropivacaine hydrochloride for 48 h; the ropivacaine+SB203580 group (Group R+S), cells were cultured with 15 mmol/L ropivacaine hydrochloride plus 10 μmol/L SB203580 for 48 h. The cell survival rates were detected by MTT assay. The protein levels of cleaved caspase-3, phosphor-p38 (p-p38) and cystolic cytochrome C (Cyt C) were detected by Western blotting.
 Results: Compared with the Group N, the number and survival rate of PC12 cells in the Group R and the Group R+S were significantly reduced (all P<0.05); the number and survival rate of PC12 cells in the Group R+S were significantly higher than those in the Group R (both P<0.05). Compared with the Group N, the levels of p-p38 and cleaved caspase-3, and the content of cytoplasmic Cyt C in the PC12 cells from the Group R and the Group R+S were significantly enhanced (all P<0.05); compared with the Group R, the levels of p-p38 and cleaved caspase-3, and the content of cytoplasmic Cyt C in the PC12 cells from the Group R+S were decreased (all P<0.05).
 Conclusion: The ropivacaine-induced cytotoxicity can be attenuated via inhibition of p38MAPK; which is related to decrease in Cyt C content and cleaved caspase-3 expression.
Anesthetics, Local ; toxicity ; Animals ; Apoptosis ; Imidazoles ; PC12 Cells ; Pyridines ; Rats ; Ropivacaine ; toxicity ; p38 Mitogen-Activated Protein Kinases ; metabolism

Anesthetics, Local ; chemistry ; pharmacology ; toxicity ; Central Nervous System ; drug effects ; Ethyl Chloride ; chemistry ; pharmacology ; toxicity ; Humans ; Inhalation ; Male ; Medical History Taking ; Neurologic Examination ; Patient Care Management ; methods ; Psychotropic Drugs ; chemistry ; pharmacology ; toxicity ; Substance-Related Disorders ; etiology ; physiopathology ; psychology ; therapy ; Treatment Outcome ; Volatilization ; Young Adult

Although local anesthetics can cause adverse drug reactions (ADRs), most ADRs to local anesthetics are from vasovagal, toxic, or anxiety reactions, while immunoglobulin E (IgE)-mediated anaphylaxis is extremely rare. We report a case of IgE-mediated anaphylactic reaction to lidocaine. A 27-year-old male patient who had two episodes of anaphylactic reactions after local injection of lidocaine was referred to our clinic for the safe use of local anesthetics for the subsequent dental procedure. Skin prick and intradermal tests were performed with amide local anesthetics; lidocaine, bupivacaine, mepivacaine, and ropivacaine. Lidocaine and mepivacaine showed positive response in prick test, and lidocaine, mepivacaine, and bupivacaine showed positive reactions in intradermal test. Only ropivacaine showed negative response both in prick and in intradermal test, and the patient was successfully treated with it. To detect serum-specific IgE, we prepared lidocaine-human serum albumin (HSA) conjugate. Enzyme-linked immunosorbent assay result showed high level of specific IgE to lidocaine-HSA conjugate in serum of the patient. This case suggests that local anesthetics can elicit specific IgE-mediated allergic reactions, and both skin prick and intradermal test should be performed in case of suspected IgE-mediated allergic response to local anesthetics.
Amides ; Anaphylaxis ; Anesthetics, Local ; Anxiety ; Bupivacaine ; Drug Toxicity ; Enzyme-Linked Immunosorbent Assay ; Humans ; Hypersensitivity ; Immunoglobulin E ; Immunoglobulins ; Intradermal Tests ; Lidocaine ; Male ; Mepivacaine ; Serum Albumin ; Skin

OBJECTIVETo observe the changes in spinal cord pathophysiology, motor function and electrophysiology after spinal cord injuries induced by punctures with different needles, and explore a new means for studying spinal neurotoxicity of local anesthetics.

METHODSA total of 144 SD rats were randomly allocated into the sham-operated group (n=36) and 3 spinal cord injury groups (n=36) with the L4-5 segment of the dura mater of the spinal cord punctured using 29G, 25G, and 21G needles. The BBB scores before surgery were recorded, and at 8 h, 24 h, 72 h, 1 week, and 2 weeks after the surgery, the motor evoked potential (MEP), spinal cord pathology and the BBB scores were examined.

RESULTSIn the control group, the rats showed normal BBB score, spinal function and microstructure. Spinal cord puncture with 29G needle did not cause obvious pathologies of the spinal cord, whereas puncture with 21G needle resulted in marked changes in the motor function, electrophysiology and histology of the spinal cord, which showed significant improvements at 2 weeks postoperatively.

CONCLUSIONPuncture with a 29G needle causes less injuries and minimal functional changes of the spinal cord, which can serve as a new means for studying spinal neurotoxicity of local anesthetics.

Anesthetics, Local ; toxicity ; Animals ; Disease Models, Animal ; Electrophysiological Phenomena ; Female ; Male ; Needles ; Rats ; Rats, Sprague-Dawley ; Recovery of Function ; Spinal Cord Injuries ; etiology ; physiopathology

Hyaluronidase is an enzyme that has temporary and reversible enzymatic effects on the matrix of connective tissue. When added to local anesthetics in pain treatments, it enhances their infiltration and dispersal into tissues. It is widely used in anesthesia for ocular, dental, and plastic surgery. Reports of drug hypersensitivity to hyaluronidase are rare and are usually confined to peribulbar or retrobulbar anesthesia during ophthalmic surgery. However, few reports exist on adverse drug reaction after epidural injection. We have observed two patients experiencing anaphylactic shock caused by hyaluronidase following epidural injection. Most of the patients with a hypersensitivity to hyaluronidase had one previous uneventful injection containing hyaluronidase, implying that sensitization had taken place. However, hypersensitivity occurring at the first administration is possible. A positive skin test can help establish the diagnosis. Although rare, the possibility of an allergic reaction to hyaluronidase should be considered even in patients with no known previous exposure.
Anaphylaxis ; Anesthesia ; Anesthetics, Local ; Connective Tissue ; Drug Hypersensitivity ; Drug Toxicity ; Humans ; Hyaluronoglucosaminidase ; Hypersensitivity ; Hypogonadism ; Injections, Epidural ; Mitochondrial Diseases ; Ophthalmoplegia ; Skin Tests ; Surgery, Plastic

BACKGROUNDLidocaine and ropivacaine are often combined in clinical practice to obtain a rapid onset and a prolonged duration of action. However, the systemic toxicity of their mixture at different concentrations is unclear. This study aimed to compare the systemic toxicity of the mixture of ropivacaine and lidocaine at different concentrations when administered intravenously in rats.

METHODSForty-eight male Wistar rats were randomly divided into 4 groups (n = 12 each): 0.5% ropivacaine (group I); 1.0% ropivacaine and 1.0% lidocaine mixture (group II); 1.0% ropivacaine and 2.0% lidocaine mixture (group III); and 1.0% lidocaine (group IV). Local anesthetics were infused at a constant rate until cardiac arrest. Electrocardiogram, electroencephalogram and arterial blood pressure were continuously monitored. The onset of toxic manifestations (seizure, dysrhythmia, and cardiac arrest) was recorded, and then the doses of local anesthetics were calculated. Arterial blood samples were drawn for the determination of local anesthetics concentrations by high-performance liquid chromatography.

RESULTSThe onset of dysrhythmia was later significantly in group IV than in group I, group II, and group III (P < 0.01), but there was no significant difference in these groups (P > 0.05). The onset of seizure, cardiac arrest in group I ((9.2 + or - 1.0) min, (37.0 + or - 3.0) min) was similar to that in group II ((9.1 + or - 0.9) min, (35.0 + or - 4.0) min) (P > 0.05), but both were later in group III ((7.5 + or - 0.7) min, (28.0 + or - 3.0) min) (P < 0.05). The onset of each toxic manifestation was significantly later in group IV than in group I (P < 0.01). The plasma concentrations of the lidocaine-alone group at the onset of dysrhythmia (DYS), cardiac arrest (CA) ((41.2 + or - 6.8) min, (59.0 + or - 9.0) min) were higher than those of the ropivacaine alone group ((20.5 + or - 3.8) min, (38.0 + or - 8.0) min) (P < 0.05). The plasma concentrations of ropivacaine inducing toxic manifestation were not significantly different among groups I, II, and III (P > 0.05).

CONCLUSIONSThe systemic toxicity of the mixture of 1.0% ropivacaine and 2.0% lidocaine is the greatest while that of 1.0% lidocaine is the least. However, the systemic toxicity of the mixture of 1.0% ropivacaine and 1.0% lidocaine is similar to that of 0.5% ropivacaine alone.

Amides ; toxicity ; Anesthetics, Local ; toxicity ; Animals ; Arrhythmias, Cardiac ; chemically induced ; Cardiovascular System ; drug effects ; Central Nervous System ; drug effects ; Heart Arrest ; chemically induced ; Lidocaine ; toxicity ; Male ; Random Allocation ; Rats ; Rats, Wistar ; Seizures ; chemically induced

OBJECTIVE: To investigate the toxicokinetics profiles of ketamine and its main metabolite norketamine in rabbits. METHODS: The rabbits were administered orally the hydrochloride of ketamine with a dose of 0.15 g/kg. The serum and urine samples were collected before administration and at different time points after drug administration. The concentrations of ketamine and norketamine were determined by GC-NPD and GC-MS. Compartment model and toxicokinetics parameters were simulated and calculated by WinNorLin program. Changes of important vital signs of rabbits were recorded during the experiment. RESULTS: The mean serum concentration-time profile of ketamine and norketamine were fitted to a two-compartment open model with first order kinetics. The kinetic equation of ketamine and norketamine were p(t) = 121.760 e(-0.0025t) +0.980 e(-0.002t) +4.579 e(-0.021 t) and p(t) = 640.919 e(-0.03 t) +1.023 e(-0.001 t) +9.784 e (-0.031 t), respectively. The peak time and the peak concentration of ketamine in serum were (40.950 +/- 12.098) min and (9.015 +/- 1.344) microg/mL, respectively. The elimination half-time of ketamine in rabbits was (430.370 +/- 28.436) min. The serum and urine showed a middle relation in concentrations of ketamine during 30-240 min after drug administration. After oral administration ketamine to rabbits, the toxic symptom on the rabbits occurred at 30 min and disappeared after 120 min. CONCLUSION The toxicokinetics parameters and kinetic equation of ketamine and norketamine in rabbits may provide the theoretical basis for forensic identification of reasonable specimen collection and inferring the time of oral administration ketamine from the ketamine concentration in serum.
Administration, Oral ; Anesthetics, Dissociative/toxicity* ; Animals ; Blood Pressure/drug effects* ; Gas Chromatography-Mass Spectrometry/methods* ; Heart Rate/drug effects* ; Ketamine/urine* ; Male ; Perceptual Disorders/etiology* ; Rabbits ; Random Allocation ; Time Factors

OBJECTIVE: To investigate the behavioral and ultrastructural changes of intrathecal administration of different concentrations of ropivacaine for 12 h. METHODS: Thirty male SD rats were randomly divided into 5 groups (6 rats in each group):group N (control), group A (ropivacaine 0.25%), group B (ropivacaine 0.5%), group C (ropivacaine 0.75%),and group D (ropivacaine 1.0%). A polyurethane microcatheter was inserted into the lumbar subarachnoid space 8 cm according to Yakshos intrathecal administration. The rats in group N received saline 0.12 mL/kg for 8 times at 1.5 h interval through the catheter, and the rats in the other groups received different concentrations of ropivacaine in the same way as in group N. The poster paw withdrawal latency to heat (PWHL) and mechanical stimulation (von Fray filament) (PWML) were measured the day before the intrathecal administration and 12 hours after the first intrathecal administration of ropivacaine. Motor function (MF) was measured after the last intrathecal administration. After the behavior test, the rats were sacrificed and the lumber segments of the spinal cord were immediately removed for electron microscopic examination. RESULTS: A total hind limb paralysis was seen at 30 seconds and intramuscular strain gradually came back 10~60 minutes after the intrathecal administration of ropivacaine in group A, B, C, and D, but not in group N. The recovery time of motor block of group A was the shortest (P<0.05), that of group D was the longest,and that of group B and C was between group A and D. Intrathecal administration of different concentrations of ropivacaine did not affect the percent maximum possible effect (%MPE) of PWHL and PWML. Electron microscopic examination showed that the spinal cords were normal in group N and A, slight edema of mitochondria and endoplasmic reticulum (ER) in group B, loosened fibrous layers in medullary sheath, edema and local degeneration of neuraxis in group C,and shrinkage of nuclear membrane, serious edema of ER, vacuolus change of mitochondria and local demyelination in group D. CONCLUSION Ropivacaine (0.5%, 0.75%, and 1.0%) administered intrathecally for 12 hours causes different degrees of ultrastructural changes in the spinal cord depending on concentrations.
Amides ; administration & dosage ; toxicity ; Anesthetics, Local ; administration & dosage ; toxicity ; Animals ; Behavior, Animal ; drug effects ; Dose-Response Relationship, Drug ; Injections, Spinal ; Male ; Microscopy, Electron ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Ropivacaine ; Spinal Cord ; ultrastructure

BACKGROUNDIsoflurane, a commonly used inhaled anesthetic, induces apoptosis in primary rat cortical neurons of rat in a concentration- and time-dependent manner by an unknown mechanism. We hypothesized that isoflurane induced apoptosis by causing abnormal calcium release from the endoplasmic reticulum (ER) via activation of inositol 1, 4, 5-trisphosphate (IP(3)) receptors. Sevoflurane has a reduced ability to disrupt intracellular calcium homeostasis and is a less potent cytotoxic agent. This study examined and compared the cytotoxic effects of isoflurane and sevoflurane on rat primary cortical neurons and their relationship with disruption of intracellular calcium homeostasis and production of reactive oxygen species (ROS).

METHODSPrimary rat cortical neurons were treated with the equivalent of 1 minimal alveolar concentration (MAC) of isoflurane and sevoflurane for 12 hours. MTT reduction and LDH release assays were performed to evaluate cell viability. Changes of calcium concentration in the cytosolic space, [Ca(2+)](c), and production of ROS were determined after exposing primary rat cortical neurons to isoflurane and sevoflurane. We also determined the effects of IP(3) receptor antagonist xestospongin C on isoflurane-induced cytotoxicity and calcium release from the ER in primary rat cortical neurons.

RESULTSIsoflurane at 1 MAC for 12 hours induced cytotoxicity in primary rat cortical neurons, which was also associated with a high and fast elevation of peak [Ca(2+)](c). Xestospongin C significantly ameliorated isoflurane cytotoxicity in primary cortical neurons, as well as inhibited the calcium release from the ER in primary cortical neurons. Isoflurane did not induce significant changes of ROS production in primary rat cortical neurons. Sevoflurane, at equivalent exposure to isoflurane, did not induce similar cytotoxicity or elevation of peak [Ca(2+)](c) in primary rat cortical neurons.

CONCLUSIONThese results suggested that isoflurane induced elevation in [Ca(2+)](c), partially via elevated activity of IP(3) receptors, which rendered cells vulnerable to isoflurane neurotoxicity. ROS production was not involved in isoflurane-induced neurotoxicity. Sevoflurane, at an equivalent exposure to isoflurane, did not induce similar elevations of [Ca(2+)](c) or neurotoxicity in primary cortical neurons of rat.

Anesthetics, Inhalation ; toxicity ; Animals ; Calcium ; metabolism ; Cell Survival ; drug effects ; Cells, Cultured ; Inositol 1,4,5-Trisphosphate Receptors ; drug effects ; physiology ; Isoflurane ; toxicity ; Methyl Ethers ; toxicity ; Rats ; Reactive Oxygen Species ; metabolism