Protective Effect of Etomidate on Spinal Cord Ischemia–Reperfusion Injury Induced by Aortic Occlusion in Rabbits

Etomidate Alleviates Ischemia-Anoxia Reperfusion Injury in Intestinal Epithelial Cells by Inhibiting the Activation of traf6-Regulated NF-KB Signaling

Objective: The present study aimed to investigate the role of etomidate in intestinal cell ischemia and hypoxia-reperfusion injury and potential mechanisms. Method: In this study, we establish the intestinal epithelial cells ischemia-reperfusion model in vitro. CCK8 was used to detect cell viability and flow cytometry assay was used to detect apoptosis levels of treated OGD/R model cells. ELISA measured the expression level of oxidative stress factors and inflammatory factors. Furthermore, western blot assay was used to detect the expression the apoptosis-related factors and TNFR-associated factors in treated OGD/R model cells. Result: Etomidate does not affect the activity of intestinal epithelial cells, and can protect intestinal epithelial cells to reduce ischemiareperfusion injury, and the expression of inflammatory factors and oxidative stress in cells with mild intestinal epithelial ischemia-reperfusion injury. Etomidate alleviates apoptosis of intestinal epithelial ischemia-reperfusion injury cells. Etomidate inhibits the activation of traf6-mediated NF-κB signal during ischemia-anoxia reperfusion of intestinal epithelial cells. Conclusion: Taken together, our study demonstrated that etomidate attenuates inflammatory response and apoptosis in intestinal epithelial cells during ischemic hypoxia-reperfusion injury and inhibits activation of NF-κB signaling regulated by TRAF6.

Etomidate Attenuates the Ferroptosis in Myocardial Ischemia/Reperfusion Rat Model via Nrf2/HO-1 Pathway

BACKGROUND

Ferroptosis has been found to play an important role in myocardial ischemia reperfusion (MIR) injury (MIRI). This study aimed to explore whether the improvement effect of Etomidate (Eto) on MIRI was related to ferroptosis.

METHODS

The MIRI rats were constructed using left anterior descending artery occlusion for 30 min followed by reperfusion for 3 h. The Eto post-conditioning was performed by Eto administration at the beginning of the reperfusion. For rescue experiments, MIRI rats were pretreated with ferroptosis inducer erastin or Nrf2 inhibitor ML385 intraperitoneally 1 h prior to MIR surgery.

RESULTS

Eto mitigated cardiac dysfunction and myocardium damage, as well as the release of creatine kinase and lactate dehydrogenase caused by ischemia/reperfusion (IR). Additionally, Eto reduced the expression of myocardial fibrosis-related proteins (collagen II and α-smooth muscle actin) and the secretion of inflammatory factors (IL-6, IL-1β, and TNF-α) in MIRI rats. Also, Eto inhibited IR-induced ferroptosis in myocardium, including reducing superoxide dismutase content, glutathione activity, and glutathione peroxidase 4 expression, while increasing the levels of malondialdehyde and iron and Acyl-CoA synthetase long-chain family member 4. Moreover, the inhibition of Eto on IR-induced myocardial fibrosis and inflammation could be eliminated by erastin. The up-regulation of Nrf2 and HO-1 protein expression, and the nuclear translocation of Nrf2 induced by Eto in the myocardial tissues of MIRI rats, could be prevented by erastin. Besides, ML385 eliminated the inhibition of Eto on ferroptosis induced by MIR.

CONCLUSIONS

Eto attenuated the myocardial injury by inhibiting IR-induced ferroptosis via Nrf2 pathway, which may provide a new idea for clinical reperfusion therapy.

Etomidate attenuates hyperoxia-induced acute lung injury in mice by modulating the Nrf2/HO-1 signaling pathway

The present study aimed to investigate the protective effects of etomidate on hyperoxia-induced acute lung injury in mice, particularly on the nuclear factor-erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway. Fifty specific pathogen-free mice were randomly divided into the blank control, model, high oxygen exposure + low etomidate dose (0.3 mg·kg^-1), a high oxygen exposure + moderate etomidate dose (3 mg·kg^-1), and a high oxygen exposure + high etomidate dose (10 mg·kg^-1) groups, with ten mice allotted per group. After 72 h, the mice were sacrificed and the lung tissues were harvested, and the wet-to-dry (W/D) ratio of the tissues was calculated. Hematoxylin-eosin staining was performed to observe the pathological changes in the lung tissues, and the lung injury score (LIS) was calculated. The mRNA and protein expression levels of Nrf2 and HO-1 were measured. The malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD) and catalase (CAT) levels were also measured, and interleukin (IL)-1β, IL-6, tumor necrosis factor alpha (TNF-α) and IL-10 concentrations in the bronchoalveolar lavage fluid were determined. At low and moderate doses, etomidate decreased pathological damage in the lung tissue, decreased the LIS and W/D ratio, upregulated Nrf2 and HO-1 mRNA and protein expression, decreased IL-1β, IL-6, and TNF-α concentrations, increased MPO activity and IL-10 levels, suppressed the production of the oxidation product MDA, and enhanced the activities of the antioxidant enzymes CAT and SOD. Within a certain dose range, etomidate enhanced antioxidant and anti-inflammatory effects in mice, thereby decreasing lung injury induced by the chronic inhalation of oxygen at high concentrations. Furthermore, the underlying mechanism may be associate with the upregulation of the Nrf2/HO-1 signaling pathway.

Etomidate alleviates cardiac dysfunction, fibrosis and oxidative stress in rats with myocardial ischemic reperfusion injury

Background

Etomidate has been shown to reduce ischemia/reperfusion (I/R) injury in several tissues. Here we aimed to investigate the protective effects of etomidate on I/R injury in Sprague-Dawley (SD) rats.

Methods

Thirty rats were randomly divided into 5 groups and pretreated with saline or 0.5/1/2 mg/kg etomidate. I/R injury was induced in all groups except the sham control group. After administration with saline or 0.5/1/2 mg/kg etomidate daily for another 27 days, rats were sacrificed and the effects of etomidate were analyzed.

Results

Treatment with etomidate dose dependently improved echocardiography indexes, ameliorated myocardial histological alterations and reduced serum creatine kinase isoenzyme (CK-MB), myoglobin (Mb) and troponin I (cTnl) levels. Fibrosis markers transforming growth factor beta (TGF-β), alpha-smooth muscle actin (α-SMA) and fibronectin was decreased with etomidate treatment. Etomidate also decreased oxidative stress and inflammation in rats, indicated by increased superoxide dismutase (SOD) and glutathione (GSH), and reduced malondialdehyde (MDA) in myocardial tissues, as well as decreased inducible NO synthase (iNOS) and increased interleukin (IL)-10 in both serum and myocardial tissues.

Conclusions

Altogether, we showed that etomidate alleviated I/R injury in rats through reduced cardiac dysfunction, fibrosis and oxidative stress. These results supported the protective role of etomidate to myocardial I/R injury.

2-(4-methyl-thiazol-5-yl) ethyl nitrate maleate-potentiated GABAA receptor response in hippocampal neurons

AIMS

2-(4-methyl-thiazol-5-yl) ethyl nitrate maleate (NMZM), a derivative of clomethiazole (CMZ), had been investigated for the treatment of Alzheimer's disease (AD). The beneficial effects of NMZM in AD included reversing cognitive deficit, improving learning and memory as well as neuroprotection. The pharmacological effects of NMZM on GABA_A receptors were reported previously; however, the mechanisms were unclear and were explored therefore.

RESULTS

In this study, we demonstrated that NMZM improved learning and memory by alleviating scopolamine-induced long-term potentiation (LTP) suppression in the dentate gyrus of rats, indicating that NMZM had protective effects against scopolamine-induced depression of LTP. Next, we investigated the action of NMZM on GABA_A receptors in hippocampal neurons and the binding site of NMZM on GABA_A receptors. NMZM directly activated GABA_A receptors in hippocampal neurons in a weak manner. However, NMZM could potentiate the response of GABA_A receptors to GABA and NMZM positively modulated GABA_A receptors with an EC₅₀ value of 465 μmol/L at 3 μmol/L GABA while this potentiation at low concentration of GABA (1, 3 μmol/L) was more significant than that at high concentration (10, 30 μmol/L). In addition, NMZM could enhance GABA currents after using diazepam and pentobarbital, the positive modulators of GABA_A receptors. NMZM could not affect the etomidate-potentiated GABA_A current. It suggested that the binding site of NMZM on GABA_A receptors is the same as etomidate.

CONCLUSIONS

These results provided support for the neuroprotective effect of NMZM, which was partly dependent on the potentiation of GABA_A receptors. The etomidate binding site might be a new target for neuronal protection and for drug development.

Effect of etomidate on the oxidative stress response and levels of inflammatory factors from ischemia-reperfusion injury after tibial fracture surgery

The effect of etomidate on the oxidative stress response and levels of inflammatory factors resulting from ischemia-reperfusion injury of the lower extremities during tibial fracture surgery were investigated. From December 2013 to June 2015, 60 tibial fracture patients with surgical indications for open reduction and internal fixation were selected. Patients were randomly divided into the observation group and the control group. All patients were stanched by tourniquet hemostasis. Patients in the observation group were anesthetized with etomidate (3–6 mg/kg·h) + remifentanil (0.1–0.25 µg/kg/min) administered with an injection pump to maintain intraoperative sedation and analgesia anesthesia. Patients in the control group received propofol (3–6 mg/kg·h) + remifentanil (0.1–0.25 µg/kg/min). Before surgery (T0), before surgery was completed and anesthesia was stopped (T1), 24 h after surgery (T3), 48 h after surgery (T4), and 1 week after surgery (T5), serum superoxide dismutase (SOD) activity was determined with a kit, and ELISA was used to measure the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-6 in peripheral blood from both groups of patients. Surgery in both groups was completed smoothly. We found that serum SOD levels of patients in the observation group were significantly higher than those of the control group, while the levels of TNF-α, IL-1, and IL-6 released by neutrophils were significantly decreased after ischemia-reperfusion injury (P<0.05). Postoperative length of stay in hospital of the observation group was significantly shorter and the occurrence rate of anesthesia complications was significantly lower than in the control group (P<0.05). In conclusion, during surgery for lower limb fracture, the use of etomidate for maintaining sedation can effectively maintain serum SOD activity and inhibit the release of inflammatory factors after ischemia-reperfusion injury of the fracture, to reduce the occurrence rate of anesthesia complications after surgery.

Current and emerging treatment options for spinal cord ischemia

Spinal cord infarction (SCI) is a rare but disabling disorder caused by a wide spectrum of conditions. Given the lack of randomized-controlled trials, contemporary treatment concepts are adapted from guidelines for cerebral ischemia, atherosclerotic vascular disease, and acute traumatic spinal cord injury. In addition, patients with SCI are at risk for several potentially life-threatening but preventable systemic and neurologic complications. Notably, there is emerging evidence from preclinical studies for the use of neuroprotection in acute ischemic injury of the spinal cord. In this review, we discuss the current state of the art for the therapy and prevention of SCI and highlight potential emerging treatment concepts awaiting translational adoption.

Neuroprotective effects of propofol, thiopental, etomidate, and midazolam in fetal rat brain in ischemia-reperfusion model

PURPOSE

The aim of this study was to investigate the neuroprotective effects of propofol, thiopental, etomidate, and midazolam as anesthetic drugs in fetal rat brain in the ischemia-reperfusion (IR) model.

METHODS

Pregnant rats of day 19 were randomly allocated into eight groups. Fetal brain ischemia was induced by clamping the utero-ovarian artery bilaterally for 30 min and reperfusion was achieved by removing the clamps for 60 min. In the control group, fetal rat brains were obtained immediately after laparotomy. In the sham group, fetal rat brains were obtained 90 min after laparotomy. In the IR group, IR procedure was performed. No treatment was given in the IR group. One milliliter intralipid solution, 40 mg/kg propofol, 3 mg/kg thiopental, 0.1 mg/kg etomidate, and 3 mg/kg midazolam was administered intraperitoneally in the vehicle group, propofol group, thiopental group, etomidate group, and midazolam group, respectively, 20 min before IR procedure. At the end of the reperfusion period, the whole brains of the fetal rats were removed for evaluation of thiobarbituric acid reactive substances and for examination by electron microscopy.

RESULTS

According to lipid peroxidation data, all the anesthetic drugs provide neuroprotection; however, ultrastructural findings and mitochondrial scoring confirms that only propofol and midazolam provides a strong neuroprotective effect.

CONCLUSIONS

Propofol and midazolam may be used to protect fetal brain in case of acute fetal distress and hypoxic injury as a first choice anesthetic drug in cesarean delivery.