Dexmedetomidine Reduces the Lidocaine-Induced Neurotoxicity by Inhibiting Inflammasome Activation and Reducing Pyroptosis in Rats.

Local anesthetic toxicity is closely related to neuronal death and activation of the inflammatory response. Dexmedetomidine (Dex) is an adrenergic α2 receptor agonist that can reduce the neurotoxicity induced by lidocaine. It also has anti-inflammatory effects. However, the mechanism underlying the neuroprotective effects of Dex against lidocaine-induced toxicity remains to be defined. We hypothesized that Dex exerts its neural protective effect through inhibiting inflammasome activation and through anti-pyroptosis effects against local anesthetic-induced nerve injury. In a rat model of lidocaine-induced spinal cord injury, we studied the protective effect of Dex on lidocaine-induced changes in spinal cord function, inflammasome formation and pyroptosis, pro-inflammatory cytokine expression, and protein kinase C (PKC)-δ phosphorylation. Dex reduced lidocaine-induced neurotoxicity and inhibited PKC-δ phosphorylation in the spinal cord of rats. Furthermore, Dex inhibited pyroptosis and inflammasome formation (caspase-1, NLRP3, and apoptosis-associated speck-like protein (ASC)). Finally, Dex attenuated interleukin (IL)-1ß and IL-18 expression, as well as microglia response. In conclusion, Dex can reduce the severity of lidocaine-induced spinal cord injury in rats by inhibiting priming and inflammasome activation and reducing pyroptosis via PKC-δ phosphorylation.

Dexmedetomidine preconditioning attenuates global cerebral ischemic injury following asphyxial cardiac arrest.

BACKGROUND/AIMS: To investigate the protection effect of dexmedetomidine preconditioning on global cerebral ischemic injury following asphyxial cardiac arrest (CA) in rats. METHODS: Seventy-two rats were randomly assigned into three groups, sham group (no asphyxia), control group (asphyxia only), and dexmedetomidine preconditioned group (asphyxia + dexmedetomidine). Dexmedetomidine was administered 5 minutes before an 8 min of asphyxia. Rats were resuscitated by a standardized method. Blood O(2) and CO(2) partial pressures were, pH, base excess (BE), and blood glucose concentration measured before asphyxial CA and 1 h after resuscitation. Neurological deficit score (NDS) was measured at 12, 24, 48, and 72 h after CA. Histopathologic changes in the hippocampal region were observed by H&E staining and histopathologic damage score. Ultrastructural morphology was observed by transmission electron microscopy. HIF-1 and VEGF expression were measured by immunostaining of serial sections obtained from brain tissue. RESULTS: Asphyxial CA -induced global cerebral ischemic decreased PaO(2), pH, BE and increased PaCO(2), blood glucose. Dexmedetomidine preconditioning improved neurologic outcome, which was associated with reduction in histopathologic injury measured by H&E staining, the histopathologic damage score and electron microscopy. Dexmedetomidine preconditioning also elevated HIF-1α and VEGF expression after global cerebral ischemia following asphyxial CA. CONCLUSION: Dexmedetomidine preconditioning protected against cerebral ischemic injury and was associated with upregulation of HIF-1α and VEGF expression.

Comparison of hemodynamics after combined spinal-epidural anesthesia between decubitus and sitting positions in aged patients undergoing total hip replacement.

OBJECTIVE: To compare the hemodynamics after combined spinal-epidural anesthesia (CSEA) between decubitus and sitting positions in aged patients undergoing total hip replacement. METHODS: A total of 80 aged patients who underwent CSEA for elective total hip replacement were randomly divided into a decubitus position group (group D) and a sitting position group (group S; each group with 40 patients). In group D, 10 mg of 0.5% bupivacaine were given into the subarachnoid space in decubitus position. In group S, 10 mg of 0.5% bupivacaine were given into the subarachnoid space in the sitting position, which was maintained for 1 min, after which the patients were in decubitus position. In both groups, the sensory block levels and changes in hemodynamics were assessed. RESULTS: The mean arterial blood pressure was significantly higher in group S than in group D at each time point within 30 min after anesthesia. There were no significant differences in heart rate between the two groups at each time point. There was also no significant difference in the level of sensory block between the two groups 20 min after the administration of CSEA. CONCLUSION: For aged patients undergoing total hip replacement, CSEA is safer and more effective in the sitting position than in decubitus position.

miR-15a and miR-16-1 downregulate CCND1 and induce apoptosis and cell cycle arrest in osteosarcoma.

Osteosarcoma, the most common primary tumor of the bones, causes many deaths due to its rapid proliferation and drug resistance. Recent studies have shown that cyclin D1 plays a key regulatory role during cell proliferation, and non-coding microRNAs (miRNAs) act as crucial modulators of cyclin D1 (CCND1). The aim of the current study was to determine the role of miRNAs in controlling CCND1 expression and inducing cell apoptosis. CCND1 has been found to be a target of miR-15a and miR-16-1 through analysis of complementary sequences between microRNAs and CCND1 mRNA. The upregulation of miR-15a and miR-16-1 in the cell line SOSP-9607 induces apoptosis and cell cycle arrest. Osteosarcoma cells transfected with miR-15a and miR-16-1 show slower proliferation curves. Moreover, the transcription of CCND1 is suppressed by miR-15a and miR-16-1 via direct binding to the CCND1 3'-untranslated region (3'-UTR). The data presented here demonstrate that the CCND1 contributes to osteosarcoma cell proliferation, suggesting that repression of CCND1 by miR-15a and miR-16-1 could be used for osteosarcoma therapy.

Prevention of propofol-induced pain in children: pretreatment with small doses of ketamine.

STUDY OBJECTIVE: To evaluate the efficacy of ketamine in preventing propofol injection pain in children. DESIGN: Prospective, randomized, double-blinded, placebo-controlled study. SETTING: University-affiliated hospital. PATIENTS: 192 ASA physical status 1 and 2 pediatric patients. INTERVENTIONS: Patients were randomly assigned to 4 groups. Group S (control) received normal saline as a placebo; Group K1, Group K3, and Group K5 received 0.1 mg/kg, 0.3 mg/kg, and 0.5 mg/kg of ketamine, respectively. Fifteen seconds after the ketamine injection, patients were injected with propofol at a rate of 12 mL/min until loss-of-eyelash reflex. MEASUREMENT: Pain was evaluated blindly at the time of induction using a 4-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain. Adverse effects were recorded. Characteristics of induction of anesthesia, such as dose of propofol and time from propofol injection to loss of consciousness (induction duration), were noted. MAIN RESULTS: 39 (84.8%) Group S (control) patients had pain. Pretreatment with ketamine reduced the frequency of pain significantly to 56.5%, 17.0%, and 14.9% in Groups K1, K3, and K5, respectively. Furthermore, the frequency of moderate and severe pain in Group K1 (21.8%), Group K3 (6.4%), and Group K5 (4.3%) was significantly (P < 0.001, respectively) reduced compared with Group S (76.1%). Moreover, the dose of propofol for induction in Group K5 was smaller than in Group S, Group K1, and Group K3 (P < 0.05). One patient in Group K5 had emergence agitation. CONCLUSION: Pretreatment with a small dose of ketamine (0.3 mg/kg) reduced the frequency and intensity of propofol injection pain without severe adverse effects.