Dexmedetomidine Oral Mucosa Patch for Sedation Suppresses Apoptosis in Hippocampus of Normal Rats

The Beneficial Effect of Preoperative dexmedetomidine in controlling postoperative pain, nausea, and Vomiting After Orthognathic Surgery: A Triple-blind Randomized Clinical Trial

PURPOSE

Controlling postoperative pain and nausea (PONV) following orthognathic surgery can be challenging. The aim of the study was to assess the efficacy of dexmedetomidine (DEX) in reducing pain and preventing nausea and vomiting in subjects undergoing orthognathic surgery.

METHODS

The authors implemented a triple-blinded, randomized clinical trial. Healthy adults with class III jaw deformity scheduled for bimaxillary orthognathic surgery were included. Subjects were randomized to the DEX or placebo groups. The DEX group received premedication with DEX 1 μg/kg IV over 10 minutes followed by a maintenance dose (0.2 μg/kg/hour). while the placebo group received normal saline. The primary outcome variables were postoperative pain, postoperative nausea, and postoperative vomiting . Pain was assessed using a visual analog scale at 1, 3, 6, 12, 18, and 24 hours, postoperatively). Nausea and vomiting were recorded throughout the postoperative period. Statistical analysis was performed using χ², t test, and repeated measures ANOVA with a P value < .05 considered significant.

RESULTS

A total of 60 consecutive subjects with a mean age of 24.6 ± 3.5 years completed the study. There were 38 females (63.33%) and 22 males (36.66%). The mean visual analog scalewas significantly lower in the DEX group at all time-points (P < .05). There was a significantly greater demand for rescue analgesics in the placebo group compared to the DEX group (P = .01). Fourteen subjects (46.7%) in the placebo group and one subject (3.3%) in the DEX group reported nausea (P < .001). Postoperative vomiting was not observed in any of the subjects.

CONCLUSION

Premedication with DEX can be considered a viable treatment option for reducing postoperative pain and postoperative nausea after bimaxillary orthognathic surgery.

Berberine Ameliorates Brain Inflammation in Poloxamer 407-Induced Hyperlipidemic Rats

Purpose

Hyperlipidemia, which promotes the development of atherosclerosis, ischemic stroke, and other forms of brain injury, can be induced by poloxamer-407. Berberine is a primary pharmacological active component of Coptidis Rhizoma that has a number of therapeutic activities. This study investigated the effects of berberine on poloxamer-407-induced brain inflammation by evaluating its effects on short-term memory, cell proliferation, inflammation, and apoptosis in the hippocampus.

Methods

To induce hyperlipidemia in a rat model, 500 mg/kg of poloxamer-407 was injected intraperitoneally. Berberine was orally administered to the rats in the berberine-treated groups once a day for 4 weeks. The step-down task avoidance task was performed to measure short-term memory. An analysis of serum lipids, immunohistochemistry for 5-bromo-2′-deoxyuridine, glial fibrillary acidic protein (GFAP), and ionized calcium-binding adapter molecule 1 (Iba1) in the dentate gyrus, and western blot analysis for Bax, Bcl-2, and cytochrome c in the hippocampus were performed.

Results

In hyperlipidemic rats, berberine reduced the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol and increased the level of high-density lipoprotein cholesterol in hyperlipidemic rats. Berberine also increased cell proliferation and short-term memory, as well as decreasing the expression of GFAP, Iba1, Bax, and cytochrome c and increasing Bcl-2 expression.

Conclusions

Berberine treatment improved short-term memory in hyperlipidemia by increasing neuronal proliferation and inhibiting neuronal apoptosis. Berberine treatment also improved lipid metabolism.

Effect of Polydeoxyribonucleotide on Lipopolysaccharide and Sevoflurane-Induced Postoperative Cognitive dysfunction in Human Neuronal SH-SY5Y Cells

Purpose

Postoperative cognitive dysfunction (POCD) is a complication of surgery characterized by acute cognitive dysfunction, memory impairment, and loss of attention. The effect of polydeoxyribonucleotide (PDRN) on the POCD environment induced by lipopolysaccharide (LPS) and sevoflurane exposure were investigated in human neuronal SH-SY5Y cells.

Methods

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and WST-8 assays were performed to determine cell viability. Cyclic adenosine-3,5′-monophosphate (cAMP), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 concentrations were measured using enzyme-linked immunoassay (ELISA). Immunocytochemistry was performed for vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF), and western blotting for TNF-α, IL-1β, IL-6, and cAMP response element-binding protein (CREB).

Results

Induction of the POCD environment reduced cell viability in the MTT and WST-8 assays. PDRN treatment reduced TNF-α, IL-1β, and IL-6 expression in POCD conditions, and significantly increased cAMP concentrations and the p-CREB/CREB ratio. PDRN treatment activated adenosine A2A receptors and then increased the expression of VEGF and BDNF, which had been reduced by LPS and sevoflurane exposure.

Conclusions

PDRN treatment showed a therapeutic effect on the LPS and sevoflurane-induced POCD environment. PDRN was shown to have an excellent therapeutic effect on POCD, not only by promoting rapid anti-inflammatory effects in damaged cells, but also by enhancing the expression of BDNF and VEGF.

Dexmedetomidine ameliorates memory impairment in sleep-deprived mice

The selective α2-adrenergic receptor agonist dexmedetomidine acts as an analgesic, sedative, and anesthetic adjuvant. The most common consequence of sleep deprivation is memory impairment. We investigated whether dexmedetomidine can counteract memory impairment caused by sleep deprivation and suppress the production of inflammatory factors. For inducing sleep deprivation, adult male mice were placed inside a water cage containing 15 platforms immersed in water up to 1 cm for 7 days. One day after sleep deprivation, dexmedetomidine at the respective dosage (5, 10, and 20 μg/kg) and α₂-adrenoceptor antagonist atipamezole (250 μg/kg) were intraperitoneally injected into the mice, once per day for six days. The step-down avoidance task and the Morris water maze test were performed. Western blot analysis was performed to determine the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB), nuclear transcription factor-κB (NF-κB), inhibitor of κBα (IκBα), and ionized calcium binding adapter molecule I (Iba-1) in the hippocampus. Immunohistochemistry was performed for the determination of Ki-67 and glial fibrillary acidic protein (GFAP) expression in the hippocampal dentate gyrus. Dexmedetomidine ameliorated sleep deprivation-induced deterioration of short-term memory and spatial learning ability. Dexmedetomidine inhibited production of inflammatory mediators caused by sleep deprivation. Dexmedetomidine also prevented the decrease in BDNF, TrkB expression, and cell proliferation induced by sleep deprivation. Dexmedetomidine could be used to counteract the neuropathological effects of sleep deprivation.

Treadmill exercise ameliorates nicotine withdrawal-induced symptoms

Nicotine withdrawal symptoms comprise insomnia, depression, anxiety, attention disorders, and increased craving. We evaluated the ameliorating effect of treadmill exercise on nicotine withdrawal symptoms. The rats in the nicotine withdrawal groups received subcutaneous injection with 6-mg/kg nicotine hydrogen tartrate salt for 17 days. And then, the injection of nicotine hydrogen tartrate salt was stopped next for 2 weeks. The rats in the exercise groups performed treadmill running once a day, 5 days per week, for 31 days. In the present results, activity was decreased and anxiety-like behavior was observed in the nicotine withdrawal rats. Treadmill running increased activity and ameliorated anxiety-like behavior in the nicotine-withdrawal rats. Expressions of tryptophan hydroxylase (TPH) and 5-hydroxytryptamine (5-HT) in the dorsal raphe were decreased in the nicotine withdrawal rats, in contrast, treadmill running increased TPH and 5-HT expressions. Impaired short-term memory and deteriorated spatial learning ability were observed in the nicotine withdrawal rats, in contrast, treadmill running ameliorated impairment of short-term memory and spatial learning ability. Expressions of brain-derived neurotrophic factor and tyrosine kinase B (TrkB) were decreased in the nicotine withdrawal rats, in contrast, treadmill running increased brain-derived neurotrophic factor and TrkB expressions. The numbers of the doublecortin (DCX)-positive cells and 5-bromo-2′-deoxyuridine (BrdU)-positive cells in the dentate gyrus were suppressed in the nicotine withdrawal rats, in contrast, treadmill running enhanced the numbers of DCX-positive cells and BrdU-positive cells. The present study demonstrate that treadmill exercise ameliorated nicotine withdrawal-induced anxiety, depression, and memory impairment.

Low-frequency electroacupncture improves locomotor function after sciatic crushed nerve injury in rats

Sciatic crushed nerve injury (SCI) causes pain-related gait and swelling in the affected limb. Electroacupuncture (EA) is a modified acupuncture technique, and analgesic effect of EA on different types of pain has been documented. Scientific functional index (SFI) is a mathematical formula to represent parameters of normal and experimental footprints. We investigated the effect of low-frequency EA on functional recovery following SCI in rats. For this study, immunohistochemistry for c-Fos in the ventral lateral periaqueductal gray (vlPAG) and paraventricular nucleus (PVN) and western blot for neurofilament (NF) and brain-derived neurotrophic factor (BDNF) in the sciatic nerve were conducted. To induce crush injury on the sciatic nerve, sciatic nerve was crushed for 30 sec using a surgical clip. The rats in the acupuncture groups received acupuncture bilaterally at respective site, once a day for 14 days. The rats in the EA group received 100-Hz electrical stimulation for 10 min once a day during 14 days. SCI decreased SFI value, in contrast, EA increased SFI value. c-Fos expression in the vlPAG and PVN was increased following SCI, in contrast, EA suppressed c-Fos expression. NF expression in the sciatic nerve was decreased by SCI, in contrast, EA increased NF expression. BDNF expression in the sciatic nerve was increased by SCI, in contrast, EA suppressed BDNF expression. In the present study, EA showed effectiveness on functional recovery from SCI.

Treadmill exercise and wheel exercise improve motor function by suppressing apoptotic neuronal cell death in brain inflammation rats

Brain inflammation is involved in many brain disorders, such as brain ischemic injury, Alzheimer diseases, and Parkinson disease. Physical exercise has been recommended for the prevention and treatment of many brain inflammatory diseases. In the present study, the effects of exercise on motor function in relation with apoptotic neuronal cell death following neuroinflammation were investigated. Moreover, we compared the effect of forced exercise with voluntary exercise on neuroinflammation-induced motor malfunction. For this study, rota-rod test, vertical pole test, foot fault test, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, immunohistochemistry for caspase-3, and western blot for Bcl-2 and Bax were performed. Lipopolysaccharide was intraventricular infused for induction of brain inflammation. Treadmill exercise and wheel exercise were conducted during 6 weeks. In the present results, Treadmill exercise and wheel exercise alleviated brain inflammation-induced motor impairments by suppressing apoptotic neuronal cell death in the motor cortex. These effects of treadmill exercise and wheel exercise were similarly appeared.

Dexmedetomidine Ameliorates Sleep Deprivation-Induced Depressive Behaviors in Mice

PURPOSE

Sleep deprivation induces depressive symptoms. Dexmedetomidine is a α2-adrenoreceptor agonist and this drug possesses sedative, anxiolytic, analgesic, and anesthetic-sparing effect. In this study, the action of dexmedetomidine on sleep deprivation-induced depressive behaviors was investigated using mice.

METHODS

For the inducing of sleep deprivation, the mice were placed inside a water cage containing 15 platforms and filled with water up to 1 cm below the platform surface for 7 days. One day after sleep deprivation, dexmedetomidine at the respective dosage (0.5, 1, and 2 μg/kg) was intraperitoneally treated into the mice, one time per a day during 6 days. Then, forced swimming test and tail suspension test were conducted. Immunohistochemistry for tyrosine hydroxylase (TH), 5-hydroxytryptamine (5-HT; serotonin), tryptophan hydroxylase (TPH) and western blot for D1 dopamine receptor were also performed.

RESULTS

Sleep deprivation increased the immobility latency in the forced swimming test and tail suspension test. The expressions of TPH, 5-HT, and D1 dopamine receptor were decreased, whereas, TH expression was increased by sleep deprivation. Dexmedetomidine decreased the immobility latency and increased the expressions of TPH, 5-HT, and D1 dopamine receptor, whereas, HT expression was decreased by dexmedetomidine treatment.

CONCLUSION

In our results, dexmedetomidine alleviated sleep deprivation-induced depressive behaviors by increasing 5-HT synthesis and by decreasing dopamine production with up-regulation of D1 dopamine receptor.

Dexmedetomidine Ameliorates Acute Stress-Induced Kidney Injury by Attenuating Oxidative Stress and Apoptosis through Inhibition of the ROS/JNK Signaling Pathway

Acute stress induces tissue damage through excessive oxidative stress. Dexmedetomidine (DEX) reportedly has an antioxidant effect. However, protective roles and related potential molecular mechanisms of DEX against kidney injury induced by acute stress are unknown. Herein, rats were forced to swim 15 min followed by restraint stress for 3 h with/without DEX (30 μg/kg). Successful model establishment was validated by an open-field test. Assessment of renal function (creatinine, urea nitrogen), histopathology, oxidative stress (malondialdehyde, glutathione, and superoxide dismutase), and apoptosis (transferase-mediated dUTP nick end labeling) was performed. Localization of apoptosis was determined by immunohistochemistry of cleaved caspase 3 protein. In addition, key proteins of the death receptor-mediated pathway, mitochondrial pathway, endoplasmic reticulum stress (ERS) pathway, and ROS/JNK signaling pathway were measured by Western blot. We found that DEX significantly improved renal dysfunction, ameliorated kidney injury, reduced oxidative stress, and alleviated apoptosis. DEX also inhibited the release of norepinephrine (NE), decreased the production of reactive oxygen species (ROS), and inhibited JNK phosphorylation. Additionally, DEX downregulated the expression of Bax, cytochrome C, cleaved caspase 9, and cleaved caspase 3 proteins in mitochondria-dependent pathways. In summary, DEX protects against acute stress-induced kidney injury in rats by reducing oxidative stress and apoptosis via inhibition of the ROS/JNK pathway.

Diosgenin improves functional recovery from sciatic crushed nerve injury in rats

Peripheral nerve injuries are commonly encountered clinical problem and often result in chronic pain and severe functional deficit. Diosgenin is a plant steroidal saponin and has anti-inflammatory and anticancer effects. In the present study, we investigated the effect of diosgenin on functional recovery following sciatic crushed nerve injury in rats. Walking track analysis for the functional recovery which can be quantified with the sciatic function index (SFI) was conducted. Immunohistochemistry for c-Fos in the ventrolateral periaqueductal gray (vlPAG) and paraventricular nucleus (PVN) and western blot for brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthesis (iNOS) in the sciatic nerve were performed. The right sciatic nerve was crushed for 30 sec using a surgical clip. The animals in the diosgenin-treated groups received orally once a day at the respective doses for 7 consecutive days, starting one day after surgery. Sciatic crushed nerve injury showed characteristic gait changes showing decrease of SFI value. Diosgenin treatment increased the SFI value and suppressed nerve injury-induced c-Fos expression in the vlPAG and PVN. Diosgenin treatment inhibited nerve injury-induced increase of BDNF, TrkB, COX-2, and iNOS expressions. It is possible that diosgenin can be used as the new therapeutic agent for pain control and functional recovery following peripheral nerve injury.