Effect of intratracheal dexmedetomidine combined with ropivacaine on postoperative sore throat: a prospective randomised double-blinded controlled trial

Background

The present study aimed to investigate whether intratracheal dexmedetomidine combined with ropivacaine reduces the severity and incidence of postoperative sore throat after tracheal intubation under general anaesthesia.

Methods

Two hundred patients with American Society of Anaesthesiologists physical status I-II who were subjected to general anaesthesia were randomly divided into four groups, namely, Group D, Group R, Group DR and Group S; these groups received intratracheal dexmedetomidine (1 µg/kg), 0.8% ropivacaine (40 mg), dexmedetomidine (1 µg/kg) combined with 0.8% ropivacaine (40 mg) and normal saline before endotracheal intubation, respectively. The primary outcomes were the incidence and grade of sore throat and hoarseness at 2 h and 24 h after surgery. Moreover, the modified Observer's Assessment of Alertness/Sedation Scale results were recorded at each time point. The secondary outcomes were intraoperative haemodynamic fluctuations, intraoperative anaesthetic drug requirements, and adverse reactions during and after surgery. The patients’ vital signs before induction, before superficial anaesthesia, after superficial anaesthesia, before intubation, after intubation, and 1 min after intubation were recorded. The use of anaesthetic drugs and occurrence of adverse effects were also recorded.

Results

The incidence and severity of sore throat were significantly lower in Group DR than in the other three groups 2 h after the operation, but they were only significantly lower in Group DR than in the control group 24 h after the operation. Moreover, compared with Group S and Group D, Group DR exhibited more stable haemodynamics during intubation. The doses of remifentanil and propofol were significantly lower in Group DR than in the other groups.

Conclusion

The combined use of dexmedetomidine and ropivacaine for surface anaesthesia before intubation significantly reduced the incidence and severity of postoperative sore throat. This treatment also decreased anaesthetic drug requirements and intraoperative haemodynamic fluctuations and caused no adverse effects.

Trial registration

This clinical research was registered at the Chinese Clinical Trial Registry (ChiCTR1900022907, Registration date 30/04/2019).

Comparison of effects of dexmedetomidine and amifostine against X-ray radiation-induced parotid damage

Radiotherapy can be employed as a therapeutic modality alone in the early stages of cancer and is used together with other treatments such as surgery and chemotherapy in more advanced stages. However, exposure to ionizing radiation in association with radiotherapy affects several organs in the head and neck and can give rise to early and late side effects. Exposure to ionizing radiation used in radiotherapy is known to cause cell damage by leading to oxygen stress through the production of free oxygen radicals (such as superoxide radicals, hydroxyl radical, hydrogen peroxide, and singlet oxygen), depending on the total radiation dosage, the fractionation rate, radiosensitivity, and linear energy transfer. The purpose of the present study was to determine the potential protective role of a powerful and highly selective α2-adrenoreceptor agonist with a broad pharmacological spectrum against salivary gland damage induced by ionizing radiation exposure. Forty Sprague-Dawley rats were divided into five groups-control, ionizing radiation, ionizing radiation + dexmedetomidine (100 µg/kg), ionizing radiation + dexmedetomidine (200 µg/kg), and ionizing radiation + amifostine (200 mg/kg). Following exposure to ionizing radiation, we observed necrosis, fibrosis, and vascular congestions in parotid gland epithelial cells. We also observed increases in malondialdehyde (MDA) and cleaved Caspase-3 levels and a decrease in glutathione (GSH). In groups receiving dexmedetomidine, we observed necrotic epithelial cells, fibrosis and vascular congestion in parotid gland tissue, a decrease in MDA levels, and an increase in GSH. Dexmedetomidine may be a promising antioxidant agent for the prevention of oxidative damage following radiation exposure.

Dexmedetomidine improved one-lung ventilation-induced cognitive dysfunction in rats

BACKGROUND

One-lung ventilation (OLV) is widely used in thoracic surgery. However, OLV may also increase CERO₂ and aggravate delayed cognitive recovery. Here, we aimed to investigate the effect of dexmedetomidine (DEX) on cognitive function in rats undergoing OLV.

METHODS

Sprague-Dawley rats were randomly divided into two-lung ventilation (TLV) group, OLV group and OLV treated with DEX group. Group DEX received 25 μg/kg DEX i.p. 30 min before induction. After mechanical ventilation (MV), Morris water maze (MWM) test was carried out to examine spatial memory function. Western blotting was used to detect pERK1/2, pCREB, Bcl-2 and BAX in hippocampal tissues. Transmission electron microscopy (TEM) was used to observe the hippocampal CA1 region.

RESULTS

Post-MV, compared with group OLV, group DEX showed increases in percentage of target quadrant time (P < 0.05), platform crossings (P < 0.05), a reduction in CERO₂ (P < 0.05), and pERK1/2, pCREB, and Bcl-2 significantly increased (P < 0.01 or P < 0.05), while BAX significantly decreased (P < 0.01), besides, a less damaged synaptic structure was observed in group DEX.

CONCLUSIONS

DEX improved post-MV cognitive function in rats undergoing OLV, reduced cerebral oxygen consumption, protected synaptic structure and upregulated ERK1/2-CREB anti-apoptotic signaling pathway in hippocampal CA1 region.

Neuroinflammation as the Underlying Mechanism of Postoperative Cognitive Dysfunction and Therapeutic Strategies

Postoperative cognitive dysfunction (POCD) is a common neurological complication following surgery and general anesthesia, especially in elderly patients. Severe cases delay patient discharge, affect the patient’s quality of life after surgery, and are heavy burdens to society. In addition, as the population ages, surgery is increasingly used for older patients and those with higher prevalences of complications. This trend presents a huge challenge to the current healthcare system. Although studies on POCD are ongoing, the underlying pathogenesis is still unclear due to conflicting results and lack of evidence. According to existing studies, the occurrence and development of POCD are related to multiple factors. Among them, the pathogenesis of neuroinflammation in POCD has become a focus of research in recent years, and many clinical and preclinical studies have confirmed the correlation between neuroinflammation and POCD. In this article, we reviewed how central nervous system inflammation occurred, and how it could lead to POCD with changes in peripheral circulation and the pathological pathways between peripheral circulation and the central nervous system (CNS). Furthermore, we proposed some potential therapeutic targets, diagnosis and treatment strategies at the cellular and molecular levels, and clinical applications. The goal of this article was to provide a better perspective for understanding the occurrence of POCD, its development, and preventive strategies to help manage these vulnerable geriatric patients.

Recent Advances in the Clinical Value and Potential of Dexmedetomidine

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has sedative, anxiolytic, analgesic, sympatholytic, and opioid-sparing properties and induces a unique sedative response which shows an easy transition from sleep to wakefulness, thus allowing a patient to be cooperative and communicative when stimulated. Recent studies indicate several emerging clinical applications via different routes. We review recent data on dexmedetomidine studies, particularly exploring the varying routes of administration, experimental implications, clinical effects, and comparative advantages over other drugs. A search was conducted on the PubMed and Web of Science libraries for recent studies using different combinations of the words “dexmedetomidine”, “route of administration”, and pharmacological effect. The current routes, pharmacological effects, and application categories of dexmedetomidine are presented. It functions by stimulating pre- and post-synaptic α2-adrenoreceptors within the central nervous system, leading to hyperpolarization of noradrenergic neurons, induction of an inhibitory feedback loop, and reduction of norepinephrine secretion, causing a sympatholytic effect, in addition to its anti-inflammation, sleep induction, bowel recovery, and sore throat reduction effects. Compared with similar α2-adrenoceptor agonists, dexmedetomidine has both pharmacodynamics advantage of a significantly greater α2:α1-adrenoceptor affinity ratio and a pharmacokinetic advantage of having a significantly shorter elimination half-life. In its clinical application, dexmedetomidine has been reported to present a significant number of benefits including safe sedation for various surgical interventions, improvement of intraoperative and postoperative analgesia, sedation for compromised airways without respiratory depression, nephroprotection and stability of hypotensive hemodynamics, reduction of postoperative nausea and vomiting and postoperative shivering incidence, and decrease of intraoperative blood loss. Although the clinical application of dexmedetomidine is promising, it is still limited and further research is required to enhance understanding of its pharmacological properties, patient selection, dosage, and adverse effects.

The effects of anaesthetics and sedatives on brain inflammation

Microglia are involved in many dynamic processes in the central nervous system (CNS) including the development of inflammatory processes and neuromodulation. Several sedative, analgesic or anaesthetic drugs, such as opioids, ∝2-adrenergic agonists, ketamine, benzodiazepines and propofol can cause both neuroprotective and harmful effects on the brain. The purpose of this review is to present the main findings on the use of these drugs and the mechanisms involved in microglial activation. Alpha 2-adrenergic agonists, propofol and benzodiazepines have several pro- or anti-inflammatory effects on microglia. Long-term use of benzodiazepines and propofol causes neuroapoptotic effects and α2-adrenergic agonists may attenuate these effects. Conversely, morphine and fentanyl may have proinflammatory effects, causing behavioural changes in patients and changes in cell viability in vitro. Conversely, chronic administration of morphine induces CCL5 chemokine expression in microglial cells that promotes their survival.

Sleep, neuronal hyperexcitability, inflammation and neurodegeneration: Does early chronic short sleep trigger and is it the key to overcoming Alzheimer's disease?

Evidence links neuroinflammation to Alzheimer's disease (AD); however, its exact contribution to the onset and progression of the disease is poorly understood. Symptoms of AD can be seen as the tip of an iceberg, consisting of a neuropathological build-up in the brain of extracellular amyloid-β (Aβ) plaques and intraneuronal hyperphosphorylated aggregates of Tau (pTau), which are thought to stem from an imbalance between its production and clearance resulting in loss of synaptic health and dysfunctional cortical connectivity. The glymphatic drainage system, which is particularly active during sleep, plays a key role in the clearance of proteinopathies. Poor sleep can cause hyperexcitability and promote Aβ and tau pathology leading to systemic inflammation. The early neuronal hyperexcitability of γ-aminobutyric acid (GABA)-ergic inhibitory interneurons and impaired inhibitory control of cortical pyramidal neurons lie at the crossroads of excitatory/inhibitory imbalance and inflammation. We outline, with a prospective framework, a possible vicious spiral linking early chronic short sleep, neuronal hyperexcitability, inflammation and neurodegeneration. Understanding the early predictors of AD, through an integrative approach, may hold promise for reducing attrition in the late stages of neuroprotective drug development.

Can Dexmedetomidine Be Effective in the Protection of Radiotherapy-Induced Brain Damage in the Rat?

Approximately 7 million people are reported to be undergoing radiotherapy (RT) at any one time in the world. However, it is still not possible to prevent damage to secondary organs that are off-target. This study, therefore, investigated the potential adverse effects of RT on the brain, using cognitive, histopathological, and biochemical methods, and the counteractive effect of the α2-adrenergic receptor agonist dexmedetomidine. Thirty-two male Sprague Dawley rats aged 5-6 months were randomly allocated into four groups: untreated control, and RT, RT + dexmedetomidine-100, and RT + dexmedetomidine-200-treated groups. The passive avoidance test was applied to all groups. The RT groups received total body X-ray irradiation as a single dose of 8 Gy. The rats were sacrificed 24 h after X-ray irradiation, and following the application of the passive avoidance test. The brain tissues were subjected to histological and biochemical evaluation. No statistically significant difference was found between the control and RT groups in terms of passive avoidance outcomes and 8-hydroxy-2'- deoxyguanosine (8-OHdG) positivity. In contrast, a significant increase in tissue MDA and GSH levels and positivity for TUNEL, TNF-α, and nNOS was observed between the control and the irradiation groups (p < 0.05). A significant decrease in these values was observed in the groups receiving dexmedetomidine. Compared with the control group, gradual elevation was determined in GSH levels in the RT group, followed by the RT + dexmedetomidine-100 and RT + dexmedetomidine-200 groups. Dexmedetomidine may be beneficial in countering the adverse effects of RT in the cerebral and hippocampal regions.

Dexmedetomidine ameliorates high-fat diet-induced nonalcoholic fatty liver disease by targeting SCD1 in obesity mice

Fatty liver disease is one of the main hepatic complications associated with obesity. To date, there are no therapeutic drugs approved for this pathology. Insulin resistance (IR) is implicated both in pathogenesis of nonalcoholic fatty liver disease (NAFLD) and in disease progression from steatosis to nonalcoholic steatohepatitis. In this study, we have characterized effects of an α2 -adrenoceptor agonist, dexmedetomidine (DEX), which can alleviate IR in hepatocytes in high-fat diet (HFD)-induced NAFLD mice. The NAFLD mice received a daily intraperitoneal administration of DEX (100 μg·kg-1 ) after 16 days exhibited lower body weight, fewer and smaller fat droplets in the liver, markedly reduced the plasma triglyceride levels, accompanied by improvement of liver damage. This inhibition of lipid accumulation activity in obese mice was associated with a robust reduction in the mRNA and protein expression of the lipogenic enzyme stearyl-coenzyme A desaturase 1 (SCD1), which was probably mediated by the inhibition of C/EBP β, PPAR γ and C/EBP α through suppressing α2A -adrenoceptor (α2A -AR) via negative feedback. Additionally, DEX can also improve IR and inflammation by inhibiting the mitogen-activated protein kinases (MAPK) and nuclear factor kappa beta (NFκB) signaling pathway in vivo. Our findings implicate that DEX may act as a potential anti-steatotic drug which ameliorates obesity-associated fatty liver and improves IR and inflammation, probably by suppressing the expression of SCD1 and the inhibition of MAPK/NFκB pathway and suggest the potential adjuvant use for the treatment of NAFLD.

CD200R Is Involved in the Anti-inflammatory Effect of Dexmedetomidine in Lipopolysaccharide-Stimulated Microglia

Dexmedetomidine has been confirmed to have anti-inflammatory effect in numerous diseases. However, the detailed mechanism is still unknown. We explore the hypothesis that CD200R is related to the anti-inflammatory effect of dexmedetomidine. Primary microglia were treated with different concentrations of dexmedetomidine followed with lipopolysaccharide (LPS) for 24 h. Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) were measured by enzyme-linked immunosorbent assay. Arginase 1 (Arg1), IL-6, and TNF-α were measured by TR-PCR. CD200R was observed by Western blot analysis. We found dexmedetomidine reduced LPS-induced IL-6 and TNF-α production and increase Arg1 in primary microglia. CD200R expression was downregulated by LPS and dexmedetomidine can attenuate the effect of LPS. Our results showed that CD200R may be related to the anti-inflammatory effect of dexmedetomidine.

Dexmedetomidine Inhibits Neuroinflammation by Altering Microglial M1/M2 Polarization Through MAPK/ERK Pathway

Neuroinflammation is critical in the pathogenesis of neurological diseases. Microglial pro-inflammatory (M1) and anti-inflammatory (M2) status determines the outcome of neuroinflammation. Dexmedetomidine exerts anti-inflammatory effects in many neurological conditions. Whether dexmedetomidine functions via modulation of microglia M1/M2 polarization remains to be fully elucidated. In the present study, we investigated the anti-inflammatory effects of dexmedetomidine on the neuroinflammatory cell model and explored the potential mechanism. BV2 cells were stimulated with LPS to establish a neuroinflammatory model. The cell viability was determined with MTT assay. NO levels were assessed using a NO detection kit. The protein levels of IL-10, TNF-α, iNOS, CD206, ERK1/2, and pERK1/2 were quantified using Western blotting. LPS significantly increased pro-inflammatory factors TNF-α and NO, and M1 phenotypic marker iNOS, and decreased anti-inflammatory factor IL-10 and M2 phenotypic marker CD206 in BV2 cells. Furthermore, exposure of BV2 cells to LPS significantly raised pERK1/2 expression. Pretreatment with dexmedetomidine attenuated LPS-elicited changes in p-ERK, iNOS, TNF-α, NO, CD206 and IL-10 levels in BV2 cells. However, co-treatment with dexmedetomidine and LM22B-10, an agonist of ERK, reversed dexmedetomidine-elicited changes in p-ERK, iNOS, TNF-α, NO, CD206 and IL-10 levels in LPS-exposed BV2 cells. We, for the first time, showed that dexmedetomidine increases microglial M2 polarization by inhibiting phosphorylation of ERK1/2, by which it exerts anti-inflammatory effects in BV2 cells.

Does Dexmedetomidine Ameliorate Postoperative Cognitive Dysfunction? A Brief Review of the Recent Literature

PURPOSE OF REVIEW

Postoperative cognitive dysfunction (POCD) occurs in 20-50% of postsurgical patients with a higher prevalence in elderly patients and patients with vascular disease and heart failure. In addition, POCD has been associated with many negative outcomes, such as increased hospital length of stay, increased rates of institutionalization, and higher patient mortality. This brief review discusses select evidence suggesting an association between neuroinflammation and POCD and whether the use of dexmedetomidine, a short-acting alpha 2 agonist, may ameliorate the incidence of POCD. We review the recent evidence for neuroinflammation in POCD, dexmedetomidine's properties in reducing inflammatory-mediated brain injury, and clinical studies of dexmedetomidine and POCD.

RECENT FINDINGS

There is evidence to support the anti-inflammatory and immunomodulatory effects of dexmedetomidine in animal models. Several clinical investigations have demonstrated favorable outcomes using dexmedetomidine over placebo for the reduction of postoperative delirium. Few studies have used high-quality endpoints for the assessment of POCD and no demonstrable evidence supports the use of dexmedetomidine for the prevention of POCD. While evidence exists for the neural anti-inflammatory properties of dexmedetomidine, human trials have yielded incomplete results concerning its use for the management of POCD. Dexmedetomidine may reduce acute postoperative delirium, but further studies are needed prior to recommending the use of dexmedetomidine for the direct reduction of POCD.

Dexmedetomidine inhibits inflammatory reaction in the hippocampus of septic rats by suppressing NF-κB pathway

Dexmedetomidine (DEX) is known to provide neuroprotective effect in the central nervous system. However, the detailed mechanism remains far more elusive. This study was designed to investigate the relevant mechanisms of DEX's neuroprotective effect. Sprague-Dawley (SD) rats were injected with dexmedetomidine and/or Lipopolysaccharide (LPS) intraperitoneally, and inflammatory cytokines in serum and in the hippocampus were measured by enzyme linked immunosorbent assay (ELISA). NF-κB in the brain tissue extracts was analyzed with western-blot. Then, we investigated whether NF-κB inhibitor prevents the elevation of inflammatory cytokines in rats injected with LPS. Our results indicated that compared with the control group, the rats exposed to LPS showed significant cognitive dysfunction. When compared to controls, the levels of TNF-α and IL-6 in the serum and hippocampus homogenate were increased in rats treated with LPS. DEX pretreatment inhibited the rats' TNF-α, IL-6 and NF-κB levels induced by LPS. In response to LPS, PDTC pretreatment restrains the production of proinflammatory cytokines (TNF-α and IL-6). Rats treated with PDTC and DEX alongside LPS exhibited less TNF-α and IL-6 than the LPS treated group. In combination, PDTC and DEX showed addictive effects. Our data suggest that DEX exerts a neuroprotective effect through NF-κB in part after LPS-induced cognitive dysfunction.

Reactive Astrogliosis in an Experimental Model of Fibromyalgia: Effect of Dexmedetomidine

To our knowledge, this is the first study which investigates the induction of neuroinflammation in rats using an acidic-saline model of fibromyalgia. It is well known that the hippocampus has a fundamental role in pain perception, and astrocytes play a crucial role in pain signaling. Our aim is to evaluate the ability of dexmedetomidine to attenuate the inflammatory responses induced in astrocytes. In a group of healthy rats, induction of chronic muscle pain by intramuscular injection of 100 µL of acidic saline on days 0 and 5 resulted in peripheral sensitization (measured using the von Frey test) and significant (<i>p</i> &#x3c; 0.05) increases in IL-1β (160.2 ± 1.1 to 335.2 ± 1.8), IL-6 (100.1 ± 1.4 to 202.4 ± 1.1), and TNF-α (60.0 ± 0.7 to 115.5 ± 1). Light and electron microscopy revealed degenerative changes in the hippocampus and reactive astrogliosis. Immunohistochemistry showed increased expression of glial fibrillary acid protein and inducible nitric oxide synthase. Surprisingly, treatment with a single dose of an α₂-adrenergic agonist, dexmedetomidine (5 µg/kg i.p.), attenuated these changes. This trial suggests that dexmedetomidine possibly directly acts on astrocytes, and a peripheral action is also suggested.

Triggering Receptor Expressed on Myeloid Cells 2 Overexpression Inhibits Proinflammatory Cytokines in Lipopolysaccharide-Stimulated Microglia

Microglia play an important role in mediating inflammatory processes in the central nervous system (CNS). Triggering receptor expressed on myeloid cells 2 (TREM2) is a microglia-specific receptor and could decrease neuropathology in Alzheimer's disease (AD). However, the detailed mechanism remains unclear. This study was designed to elucidate the effect of TREM2 on microglia. We showed that lipopolysaccharide (LPS) stimulation significantly increases proinflammatory cytokines and suppressed TREM2 in microglia. In addition, TREM2 overexpression inhibited LPS-induced microglia activation and elevated M2 phenotype of microglia. Together, our results demonstrate that TREM2 overexpression reduced LPS-induced proinflammatory cytokine release in microglia and increased M2 phenotype of microglia. These findings provide novel insights that the regulation of microglia polarization may be an approach for ameliorating microglia inflammation in neurodegenerative diseases.

Dexmedetomidine May Produce Extra Protective Effects on Sepsis-induced Diaphragm Injury

OBJECTIVE

The objective was to evaluate the protective effects of dexmedetomidine (DEX), a selective agonist of α2-adrenergic receptor, on sepsis-induced diaphragm injury and the underlying molecular mechanisms.

DATA SOURCES

The data used in this review were mainly from PubMed articles published in English from 1990 to 2015.

STUDY SELECTION

Clinical or basic research articles were selected mainly according to their level of relevance to this topic.

RESULTS

Sepsis could induce severe diaphragm dysfunction and exacerbate respiratory weakness. The mechanism of sepsis-induced diaphragm injury includes the increased inflammatory cytokines and excessive oxidative stress and superfluous production of nitric oxide (NO). DEX can reduce inflammatory cytokines, inhibit nuclear factor-kappaB signaling pathways, suppress the activation of caspase-3, furthermore decrease oxidative stress and inhibit NO synthase. On the basis of these mechanisms, DEX may result in a shorter period of mechanical ventilation in septic patients in clinical practice.

CONCLUSIONS

Based on this current available evidence, DEX may produce extra protective effects on sepsis-induced diaphragm injury. Further direct evidence and more specific studies are still required to confirm these beneficial effects.

Dexmedetomidine Modulates Histamine-induced Ca(2+) Signaling and Pro-inflammatory Cytokine Expression

Dexmedetomidine is a sedative and analgesic agent that exerts its effects by selectively agonizing α2 adrenoceptor. Histamine is a pathophysiological amine that activates G protein-coupled receptors, to induce Ca(2+) release and subsequent mediate or progress inflammation. Dexmedetomidine has been reported to exert inhibitory effect on inflammation both in vitro and in vivo studies. However, it is unclear that dexmedetomidine modulates histamine-induced signaling and pro-inflammatory cytokine expression. This study was carried out to assess how dexmedetomidine modulates histamine-induced Ca(2+) signaling and regulates the expression of pro-inflammatory cytokine genes encoding interleukin (IL)-6 and -8. To elucidate the regulatory role of dexmedetomidine on histamine signaling, HeLa cells and human salivary gland cells which are endogenously expressed histamine 1 receptor were used. Dexmedetomidine itself did not trigger Ca(2+) peak or increase in the presence or absence of external Ca(2+). When cells were stimulated with histamine after pretreatment with various concentrations of dexmedetomidine, we observed inhibited histamine-induced [Ca(2+)]i signal in both cell types. Histamine stimulated IL-6 mRNA expression not IL-8 mRNA within 2 hrs, however this effect was attenuated by dexmedetomidine. Collectively, these findings suggest that dexmedetomidine modulates histamine-induced Ca(2+) signaling and IL-6 expression and will be useful for understanding the antagonistic properties of dexmedetomidine on histamine-induced signaling beyond its sedative effect.

Neuroprotective effect of dexmedetomidine on hyperoxia-induced toxicity in the neonatal rat brain

Dexmedetomidine is a highly selective agonist of α2-receptors with sedative, anxiolytic, analgesic, and anesthetic properties. Neuroprotective effects of dexmedetomidine have been reported in various brain injury models. In the present study, we investigated the effects of dexmedetomidine on neurodegeneration, oxidative stress markers, and inflammation following the induction of hyperoxia in neonatal rats. Six-day-old Wistar rats received different concentrations of dexmedetomidine (1, 5, or 10 µg/kg bodyweight) and were exposed to 80% oxygen for 24 h. Sex-matched littermates kept in room air and injected with normal saline or dexmedetomidine served as controls. Dexmedetomidine pretreatment significantly reduced hyperoxia-induced neurodegeneration in different brain regions of the neonatal rat. In addition, dexmedetomidine restored the reduced/oxidized glutathione ratio and attenuated the levels of malondialdehyde, a marker of lipid peroxidation, after exposure to high oxygen concentration. Moreover, administration of dexmedetomidine induced downregulation of IL-1β on mRNA and protein level in the developing rat brain. Dexmedetomidine provides protections against toxic oxygen induced neonatal brain injury which is likely associated with oxidative stress signaling and inflammatory cytokines. Our results suggest that dexmedetomidine may have a therapeutic potential since oxygen administration to neonates is sometimes inevitable.