Mijung Yeom

Effect of electroacupuncture on the stress-induced changes in brain-derived neurotrophic factor expression in rat hippocampus

Stress induces neuronal atrophy and death especially in the hippocampus. Alterations in the expression of neurotrophic factors are implicated in stress-induced hippocampal degeneration. In the hippocampus, stress decreases brain-derived neurotrophic factor (BDNF) mRNA levels. In oriental medicine, acupuncture has long been employed as a treatment of numerous disorders. The objective of this study was to examine whether electroacupuncture (EA) stimulation can influence BDNF expression in the hippocampus of rats exposed to immobilization stress. Rats were immobilized in plastic bags, and then subjected to EA at ST36 Zusanli. After treatment, the animals were decapitated and the hippocampi were rapidly removed and processed for RNA isolation and reverse transcription. Real-time polymerase chain reaction analysis showed that EA stimulation significantly restored BDNF mRNA expression declined by immobilization stress. The results suggest that EA may relieve neuropathological effects of stress by modulating neurotrophic factor expression.

Effect of wild ginseng on scopolamine‐induced acetylcholine depletion in the rat hippocampus

Objectives The ameliorating effects of wild ginseng on learning and memory deficits were investigated in rats.

Lactoferrin inhibits the inflammatory and angiogenic activation of bovine aortic endothelial cells

ObjectiveLactoferrin (Lf) is known to have anti-cancer and anti-inflammatory activities; however, its therapeutic mechanism has not been defined. In this study, to explain the therapeutic mechanism of Lf, we examined the effect of Lf on endothelial cell activation, leukocyte integration, and angiogenesis in vitro.MethodsEndothelia-leukocyte adhesion assays were used to assess primary cultures of bovine aortic endothelial cells (BAECs) activation following LPS treatment. The mRNA expression of ICAM-1 and proinflammatory cytokines was measured using RT-PCR. Each step of angiogenesis was evaluated in vitro, including endothelial cell proliferation, migration, and tube formation. Proliferation was examined using WST-1 and BrdU incorporation assays, while wound migration assays were used to evaluate cell migration; capillary-like tube formation assays on Matrigel were used to assess tube formation.ResultsLf reduced the adhesion of human monocyte-like THP-1 cells to BAECs by 45%. Lf also reduced mRNA expression of ICAM-1 and proinflammatory cytokines in BAECs. Lf significantly inhibited BAEC proliferation, migration, and tube formation.ConclusionsLf exerted a potent effect on BAEC activation, suggesting that it might function via an endothelia-based mechanism in the treatment of various diseases, including rheumatoid arthritis and cancer.

Effect of Berberine on Depression- and Anxiety-Like Behaviors and Activation of the Noradrenergic System Induced by Development of Morphine Dependence in Rats

The purpose of this study was to evaluate whether berberine (BER) administration could attenuate depression- and anxiety-like behaviors and increase corticotrophin-releasing factor (CRF) and tyrosine hydroxylase (TH) expression following chronic morphine withdrawal in rats. Male rats were exposed to chronic, intermittent, escalating morphine (10~50 mg/kg) for 10 days. After the last morphine injection, depression- and anxiety-like beahvior associated with morphine discontinuation persisted for at least three days during withdrawal without any change in ambulatory activity. Daily BER administration significantly decreased immobility in the forced swimming test and increased open-arm exploration in the elevated plus maze test. BER administration also significantly blocked the increase in hypothalamic CRF expression and TH expression in the locus coeruleus (LC) and the decrease in hippocampal brain-derived neurotrophic factor (BDNF) mRNA expression. Taken together, these findings demonstrated that BER administration significantly reduced morphine withdrawal-associated behaviors following discontinuation of repeated morphine administration in rats, possibly through modulation of hypothalamic CRF and the central noradrenergic system. BER may be a useful agent for treating or alleviating complex withdrawal symptoms and preventing morphine use relapses.

Xanthii fructus inhibits inflammatory responses in LPS-stimulated RAW 264.7 macrophages through suppressing NF-κB and JNK/p38 MAPK

ETHNOPHARMACOLOGICAL RELEVANCE Xanthii fructus (XF) has long been used to treat a variety of inflammatory conditions in Korean traditional medicine, but the underlying mechanisms that could explain the anti-inflammatory actions of XF remain largely unknown. AIM OF THE STUDY This study aimed to elucidate the anti-inflammatory effects of X. fructus (XF) and to examine its underlying molecular mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. MATERIALS AND METHODS The effect of XF on LPS-induced mRNA and protein expressions of inflammatory mediators and cytokines were determined. Moreover, the activation of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways and the expression of heme oxygenase-1 (HO-1) were explored to elucidate the anti-inflammatory mechanisms. RESULTS XF significantly inhibited LPS-induced production of inflammatory mediators, interleukin-6 (IL-6), nitric oxide (NO), and prostaglandin E2 (PGE2), without any cytotoxicity. However, it did not affect tissue necrosis factor (TNF)-α or IL-1β production in LPS-stimulated RAW 264.7 cells. Expression levels of inducible nitric oxide synthase (iNOS) mRNA and protein were inhibited dose-dependently by XF in LPS-stimulated RAW 264.7 cells, but there were no changes in cyclooxygenase-2 (COX-2) mRNA and protein. XF significantly attenuated LPS-induced phosphorylation and degradation of inhibitory kappa Bα (IκBα) and consequently reduced the nuclear translocation of p65 NF-κB. Pretreatment with XF also strongly inhibited the LPS-induced phosphorylation of p38 kinase and JNK, whereas the phosphorylation of ERK1/2 was not affected. In addition, XF led to an increase in HO-1 expression. CONCLUSION Taken together, our findings support that XF inhibits LPS-induced inflammatory responses by blocking NF-κB activation, inhibiting JNK/p38 MAPK phosphorylation, and enhancing HO-1 expression in macrophages, suggesting that it could be an attractive therapeutic candidate for various inflammatory diseases.

Oral administration of glucosylceramide ameliorates inflammatory dry-skin condition in chronic oxazolone-induced irritant contact dermatitis in the mouse ear

BACKGROUND Irritant contact dermatitis (ICD) is an inflammatory skin disease triggered by exposure to a chemical that is toxic or irritating to the skin. A major characteristic of chronic ICD is an inflammatory dry-skin condition with associated itching. Although glucosylceramide (GlcCer) is known to improve the skin barrier function, its mechanism of action is unknown. OBJECTIVES Using a mouse model of oxazolone-induced chronic ICD, this study investigated the effects of oral administration of GlcCer on inflammatory dry skin. METHODS Chronic ICD was induced by repeated application of oxazolone in mice. GlcCer was orally administered once daily throughout the elicitation phase. The beneficial efficacy of GlcCer on cutaneous inflammation was evaluated by assessing ear thickness, lymph node weight, histological findings, and mRNA expression of pro-inflammatory cytokines such as IL-1β and IL-6. Additionally, parameters of the itch-associated response, including scratching behavior, water content of the skin, and aquaporin-3 levels in the lesional ear, were measured. RESULTS Oral GlcCer administration significantly suppressed mRNA expression of the pro-inflammatory cytokines IL-1β and IL-6. GlcCer also suppressed ear swelling, lymph node weight gains, and infiltration of leukocytes and mast cells in ICD mice. In oxazolone-induced ICD mice, GlcCer significantly inhibited irritant-related scratching behavior and dehydration of the stratum corneum, and decreased aquaporin-3 expression. CONCLUSIONS Our results indicate that GlcCer suppressed inflammation not only by inhibiting cytokine production but also by repairing the skin barrier function, suggesting a potential beneficial role for GlcCer in the improvement of chronic ICD.

Chronic Administration of Baicalein Decreases Depression-Like Behavior Induced by Repeated Restraint Stress in Rats

Baicalein (BA), a plant-derived active flavonoid present in the root of Scutellaria baicalensis, has been widely used for the treatment of stress-related neuropsychiatric disorders including depression. Previous studies have demonstrated that repeated restraint stress disrupts the activity of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in depression. The behavioral and neurochemical basis of the BA effect on depression remain unclear. The present study used the forced swimming test (FST) and changes in brain neurotransmitter levels to confirm the impact of BA on repeated restraint stress-induced behavioral and neurochemical changes in rats. Male rats received 10, 20, or 40 mg/kg BA (i.p.) 30 min prior to daily exposure to repeated restraint stress (2 h/day) for 14 days. Activation of the HPA axis in response to repeated restraint stress was confirmed by measuring serum corticosterone levels and the expression of corticotrophin-releasing factor in the hypothalamus. Daily BA administration significantly decreased the duration of immobility in the FST, increased sucrose consumption, and restored the stress-related decreases in dopamine concentrations in the hippocampus to near normal levels. BA significantly inhibited the stress-induced decrease in neuronal tyrosine hydroxylase immunoreactivity in the ventral tegmental area and the expression of brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus. Taken together, these findings indicate that administration of BA prior to the repeated restraint stress significantly improves helpless behaviors and depressive symptoms, possibly by preventing the decrease in dopamine and BDNF expression. Thus, BA may be a useful agent for the treatment or alleviation of the complex symptoms associated with depression.

Acupuncture manipulation enhances anti-nociceptive effect on formalin-induced pain in rats

Abstract Objectives: In order to apply appropriate acupuncture stimulation, different needle manipulation techniques are required. These manipulations are performed in many ways such as twirling the needle, varying the insertion angle, etc. The present study was designed to evaluate the antinociceptive effect of these manipulations to the acupuncture point ST36 on formalin-induced pain in rats. Methods: Animals were divided into four groups: non-treated control (CON), acupuncture without manipulation (AT), acupuncture with twirling manipulation (TM) and acupuncture with lifting–thrusting manipulation (LM) group. Level of pain was measured in formalin-injected rats in the early (0–10 minutes) and the late (10–60 minutes) phase. Several pain-related gene expressions were investigated in the spinal cord using reverse transcriptase-polymerase chain reaction analysis. Results: Formalin-induced pain was significantly reduced in the TM and the LM groups, compared with the CON and the AT groups. TM was more effective than LM in both phases. Needle manipulation was also effective in suppressing the mRNA expression of pain-related genes such as Fos, opioid receptor-like 1, tachykinin 1, tachykinin receptor 1, μ-opioid receptor and 5-hydroxytryptamine receptor 2A in the spinal cord. Discussion: The TM and the LM groups showed enhanced analgesia, compared with the AT group. This effect might be related to the suppression of the transcription of pain-related genes.

Effects of systemic administration of ibuprofen on stress response in a rat model of post-traumatic stress disorder

Pro-inflammatory cytokine and brain-derived neurotrophic factor (BDNF) are modulated in post-traumatic stress disorder (PTSD). This study investigated the effects of ibuprofen (IBU) on enhanced anxiety in a rat model of PTSD induced by a single prolonged stress (SPS) procedure. The effects of IBU on inflammation and BDNF modulation in the hippocampus and the mechanisms underlying for anxiolytic action of IBU were also investigated. Male Sprague-Dawley rats were given IBU (20 or 40 mg/kg, i.p., once daily) for 14 days. Daily IBU (40 mg/kg) administration signifi cantly increased the number and duration of open arm visits in the elevated plus maze (EPM) test, reduced the anxiety index in the EPM test, and increased the time spent in the center of an open fi eld after SPS. IBU administration signifi cantly decreased the expression of pro-inflammatory mediators, such as tumor necrosis factor-α, interleukin-1β, and BDNF, in the hippocampus, as assessed by reverse transcription-polymerase chain reaction analysis and immunohistochemistry. These fi ndings suggest that IBU exerts a therapeutic effect on PTSD that might be at least partially mediated by alleviation of anxiety symptoms due to its anti-inflammatory activity and BDNF expression in the rat brain.

L-Tetrahydropalmatine Ameliorates Development of Anxiety and Depression-Related Symptoms Induced by Single Prolonged Stress in Rats

Abnormal adaptation of the stress-response system following traumatic stress can lead to alterations in the hypothalamic-pituitary-adrenal (HPA) axis that may contribute to the development of post-traumatic stress disorder (PTSD). The present study used several behavioral tests to investigate the anxiolytic-like and antidepressant activity of L-tetrahydropalmatine (L-THP) in an experimental rat model of anxiety and depression induced by single prolonged stress (SPS), an animal model of PTSD. Male rats were treated intraperitoneally (i.p.) with vehicle or varied doses of THP 30 min prior to SPS for 8 consecutive days. Daily THP (50 mg/kg) administration significantly increased the number and duration of open arm visits in the elevated plus maze (EPM) test, reduced the anxiety index, increased the risk assessment, and increased the number of head dips over the borders of the open arms after SPS. THP was also associated with increased time spent at the center of the open field, reduced grooming behaviors in the EPM test, and reduced time spent immobile in the forced swimming test (FST). It also blocked the decrease in neuropeptide Y (NPY) and the increase in corticotrophin-releasing factor (CRF) expression in the hypothalamus. This is the first study to determine that THP exerts pronounced anxiolytic-like and antidepressant effects on the development of the behavioral and biochemical symptoms associated with PTSD, indicating its prophylactic potential. Thus, THP reversed several behavioral impairments triggered by the traumatic stress of SPS and is a potential non-invasive therapeutic intervention for PTSD.