Terpenoids from Abies holophylla Attenuate LPS-Induced Neuroinflammation in Microglial Cells by Suppressing the JNK-Related Signaling Pathway.

We have previously reported that phytochemicals from Abies holophylla exhibit anti-inflammatory and neuroprotective effects by decreasing nitrite production and increasing nerve growth factor production. However, the exact mechanism underscoring these effects has not been revealed. In the present study, we aimed to explore the underlying anti-inflammatory mechanisms of A. holophylla and its phytochemicals. We studied various solvent fractions of A. holophylla and found the chloroform and hexane sub-fractions showed the most significant anti-neuroinflammatory effects in lipopolysaccharide (LPS)-activated murine microglia. Concomitantly, the terpenoids isolated from chloroform and hexane fractions showed similar anti-neuroinflammatory effects with significant inhibition of NO and reactive oxygen species production, and decreased protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase. Interestingly, these terpenoids inhibited the phosphorylation of c-Jun N-terminal kinase (JNK), which further inhibited the production of pro-inflammatory mediators, including prostaglandin E2, tumor necrosis factor, and interleukins (IL-6 and IL-1ß), with a potency greater than that of the well-known iNOS inhibitor NG-mono-methyl-L-arginine (L-NMMA). These results suggest that the chloroform- and hexane-soluble fraction mediated the mitogen-activated protein kinase (MAPK) inhibition, in particular the JNK pathway, thereby lowering the inflammatory cascades in LPS-activated murine microglia. Thus, our study suggests that the chloroform and hexane fractions of A. holophylla and their terpenoids may be potential drug candidates for drug discovery against LPS-induced neuroinflammation and neuroinflammatory-related neurodegeneration.

Yokukansan, a Japanese Herbal Medicine, Suppresses Substance PInduced Production of Interleukin-6 and Interleukin-8 by Human U373 MG Glioblastoma Astrocytoma Cells.

BACKGROUND: Yokukansan is a traditional Japanese herbal medicine that has an antiallodynic effect in patients with chronic pain. However, the mechanisms by which yokukansan inhibits neuropathic pain are unclear. OBJECTIVE: This study aimed to investigate the molecular effects of yokukansan on neuroinflammation in U373 MG glioblastoma astrocytoma cells, which express a functional high-affinity neurokinin 1 receptor (substance P receptor), and produce interleukin (IL)-6 and IL-8 in response to stimulation by substance P (SP). METHODS: We assessed the effect of yokukansan on the expression of ERK1/2, P38 MAPK, nuclear factor (NF)-κB, and cyclooxygenase-2 (COX-2) in U373 cells by western blot assay. Levels of IL-6 and IL-8 in conditioned medium obtained after stimulation of cells with SP for 24 h were measured by enzyme-linked immunosorbent assay. All experiments were conducted in triplicate. Results were analyzed by one-way ANOVA, and significance was accepted at p < 0.05. RESULTS: Yokukansan suppressed SP-induced production of IL-6 and IL-8 by U373 MG cells, and downregulated SP-induced COX-2 expression. Yokukansan also inhibited phosphorylation of ERK1/2 and p38 MAPK, as well as nuclear translocation of NF-κB, induced by SP stimulation of U373 MG cells. CONCLUSION: Yokukansan exhibits anti-inflammatory activity by suppressing SP-induced production of IL-6 and IL-8 and downregulating COX-2 expression in U373 MG cells, possibly via inhibition of the activation of signaling molecules, such as ERK1/2, p38 MAPK, and NF-κB.

Inflammatory and oxidative mechanisms potentiate bifenthrin-induced neurological alterations and anxiety-like behavior in adult rats.

Bifenthrin (BF) is a synthetic pyrethroid pesticide widely used in several countries to manage insect pests on diverse agricultural crops. Growing evidence indicates that BF exposure is associated with an increased risk of developing neurodegenerative disorders. However, the mechanisms by which BF induces neurological and anxiety alterations in the frontal cortex and striatum are not well known. The present in vivo study was carried out to determine whether reactive oxygen species (ROS)-mediated oxidative stress (OS) and neuroinflammation are involved in such alterations. Thirty-six Wistar rats were thus randomly divided into three groups and were orally administered with BF (0.6 and 2.1 mg/kg body weight, respectively) or the vehicle (corn oil), on a daily basis for 60 days. Results revealed that BF exposure in rats enhanced anxiety-like behavior after 60 days of treatment, as assessed with the elevated plus-maze test by decreases in the percentage of time spent in open arms and frequency of entries into these arms. BF-treated rats also exhibited increased oxidation of lipids and carbonylated proteins in the frontal cortex and striatum, and decreased glutathione levels and antioxidant enzyme activities including superoxide dismutase, catalase and glutathione peroxidase. Treatment with BF also increased protein synthesis and mRNA expression of the inflammatory mediators cyclooxygenase-2 (COX-2), microsomal prostaglandin synthase-1 (mPGES-1) and nuclear factor-kappaBp65 (NF-kBp65), as well as the production of tumor necrosis factor-α (TNF-α) and ROS. Moreover, BF exposure significantly decreased protein synthesis and mRNA expression of nuclear factor erythroid-2 (Nrf2) and acetylcholinesterase (AChE), as well as gene expression of muscarinic-cholinergic receptors (mAchR) and choline acetyltransferase (ChAT) in the frontal cortex and striatum. These data suggest that BF induced neurological alterations in the frontal cortex and striatum of rats, and that this may be associated with neuroinflammation and oxidative stress via the activation of Nrf2/NF-kBp65 pathways, which might promote anxiety-like behavior.

Astaxanthin offers neuroprotection and reduces neuroinflammation in experimental subarachnoid hemorrhage.

BACKGROUND: Neuroinflammation has been proven to play a crucial role in early brain injury pathogenesis and represents a target for treatment of subarachnoid hemorrhage (SAH). Astaxanthin (ATX), a dietary carotenoid, has been shown to have powerful anti-inflammation property in various models of tissue injury. However, the potential effects of ATX on neuroinflammation in SAH remain uninvestigated. The goal of this study was to investigate the protective effects of ATX on neuroinflammation in a rat prechiasmatic cistern SAH model. METHODS: Rats were randomly distributed into multiple groups undergoing the sham surgery or SAH procedures, and ATX (25 mg/kg or 75 mg/kg) or equal volume of vehicle was given by oral gavage at 30 min after SAH. All rats were sacrificed at 24 h after SAH. Neurologic scores, brain water content, blood-brain barrier permeability, and neuronal cell death were examined. Brain inflammation was evaluated by means of expression changes in myeloperoxidase, cytokines (interleukin-1ß, tumor necrosis factor-α), adhesion molecules (intercellular adhesion molecule-1), and nuclear factor kappa B DNA-binding activity. RESULTS: Our data indicated that post-SAH treatment with high dose of ATX could significantly downregulate the increased nuclear factor kappa B activity and the expression of inflammatory cytokines and intercellular adhesion molecule-1 in both messenger RNA transcription and protein synthesis. Moreover, these beneficial effects lead to the amelioration of the secondary brain injury cascades including cerebral edema, blood-brain barrier disruption, neurological dysfunction, and neuronal degeneration. CONCLUSIONS: These results indicate that ATX treatment is neuroprotective against SAH, possibly through suppression of cerebral inflammation.

Furanodien-6-one from Commiphora erythraea inhibits the NF-κB signalling and attenuates LPS-induced neuroinflammation.

We investigated the in vitro anti-inflammatory activity of 1(10),4-furanodien-6-one, one the most active compounds of the hexane extract of Commiphora erythraea (Ehrenb.) Engl., by exposing microglial BV-2 cells to lipopolysaccharide. We showed that furanodien-6-one pre-treatment restored cell viability and ROS to control levels while halving NO generation. Production of pro-inflammatory IL-6, IL-23, IL-17, TGF-ß, and INF-γ, significantly induced by LPS, was also markedly reduced by furanodien-6-one treatment. We further showed that furanodien-6-one protects primary neuronal cultures against the inflammatory/toxic insults of LPS-treated BV-2 conditioned media, indicating that furanodien-6-one exerts anti-inflammatory/cytoprotective effects in neuronal cells. We then investigated whether furanodien-6-one exerts anti-inflammatory properties in an in vivo model of microglial activation. In adult mice ip-injected with LPS we found that furanodien-6-one had strong cerebral anti-inflammatory properties by inhibiting liver and brain TNFα as well as IL-1ß expression. Results were not unexpected since FTIR-metabolomic analyses showed that furanodien-6-one-treated mice had a reduced dissimilarity to control animals and that the response to LPS treatment was markedly modified by furanodien-6-one. In conclusion our data provide strong evidence of the anti-inflammatory properties of furanodien-6-one that could be exploited to counteract degenerative pathologies based on neuroinflammation.

Anti-inflammatory and analgesic effects of yaotuitong capsules in experimental rats with chemically induced radicular neuritis.

OBJECTIVE: The aims of this study were to determine the anti-inflammatory and analgesic effects of Yaotuitong (translation: low back and leg pain) capsules, a Chinese herbal preparation, and the histological changes it induces in experimental rats with chemically induced radicular neuritis. METHODS: Wistar rats were randomly divided into normal, model, Western medicine, and traditional Chinese medicine groups (n=24 per group). We surgically duplicated a chemical radicular neuritis model to simulate lumbar intervertebral disc protrusion. Granuloma formation was measured on postoperative days (PODs) 3, 7, 14, and 21. Prostaglandin E2 and 5-hydroxytryptamine (inflammation mediators) levels in the surrounding tissue and the histology of the nerve root were determined on PODs 7 and 14. RESULTS: Yaotuitong capsules significantly reduced prostaglandin E2 (P<0.01) and 5-hydroxytryptamine (P<0.01) levels in tissue surrounding the nerve root. It also inhibited granuloma formation (P<0.05). CONCLUSION: Yaotuitong capsules have anti-inflammatory and analgesic effects that can alleviate the discomfort of lumbar intervertebral disc protrusion.

Augmented expression of daintain/allograft inflammatory factor-1 is associated with clinical disease: dynamics of daintain/allograft inflammatory factor-1 expression in spleen, peripheral nerves and sera during experimental autoimmune neuritis.

Experimental autoimmune neuritis (EAN) is an animal model of Guillain-Barré syndrome, characterized by inflammation and demyelination of the peripheral nervous system (PNS). Daintain/allograft inflammatory factor-1 (daintain/AIF-1) is a novel interferon-gamma-inducible protein expressed by macrophages during organ specific autoimmune diseases. To study the involvement of daintain/AIF-1 in EAN we induced EAN in Lewis rats by immunizing with bovine PNS myelin (BPM) and complete Freund's adjuvant (CFA). The expression of daintain/AIF-1 was examined in the spleen, peripheral nerves and sera during the course of EAN by immunohistochemistry and radioimunoassay (RIA). The expression of daintain/AIF-1 in the spleen and in the sciatic nerves peaked at the preclinical stage (day 7 post immunization (p.i.)) and at the height (day 15 p.i.) of clinical EAN, consistent with a disease promoting role for daintain/AIF-1. Daintain/AIF-1 expressing cells represented a subset of ED1+ or CD11b/c+ mononuclear cells. A significant increase of daintain/AIF-1-like immunoreactivity in sera occurred at the preclinical stage of EAN. Taken together, these data indicate that daintain/AIF-1 may play a proinflammatory role in the pathogenesis of EAN.

[Effect electroacupuncture on the neurogenic inflammation].

The neurogenic inflammation caused by antidromic stimulation of the saphenous nerve was taken as an index of peripheral release of substance P. Electroacupuncture could reduce the plasma extravasation from the neurogenic inflammation by 69.7%, but electroacupuncture per se did not cause obvious plasma extravasation. In rats pretreated with capsaicin the plasma extravasation could be markedly reduced, in consistent with the reduction of substance P-like immunoreactivity in dorsal horn. It is referred that electroacupuncture might block the conveying the signals induced by nerve stimulation along the C-fibers and the axo-axonal reflex, leading to the reduction of peripheral release of substance P. Besides the mediation by different central structures, acupuncture might have direct effects on regulating peripherally the release of some inflammatory and painful mediators.

Experimental allergic neuritis in the Lewis rat: characterization of the activity of peripheral myelin and its major basic protein,P2.

Experimental allergic neuritis has been produced in the inbred Lewis rat in the absence of experimental allergic encephalomyelitis (EAE) using bovine intradural root myelin. The lack of EAE is probably because P1 is only weakly encephalitogenic in the rat. One of the basic proteins of bovine peripheral myelin, P2, was isolated and demonstrated to be pure by amino acid analysis and SDS PAGE. It was found to have a molecular weight of 15,400 and contained 4 mol 1/2-cystine/mol. This P2 was found to be highly neuritogenic and is probably the sole neuritogenic antigen in this system. The successful demonstration of its neuritogenicity must be due in large part to the use of the inbred Lewis rat and bovine P2, but an explanation could also involve the omission of denaturing organic solvents, the prevention of oxidative denaturation and presumably the fact that any changes which may occur are not sufficient to prevent recognition of the active site by the immune system of the inbred Lewis rat. P2 was neuritogenic down to 5 micrograms/animal. Its activity was enhanced by but not dependent on the presence of Mycobacterium in the adjuvant. This suggested that release of P2 could possibly break tolerance and produce an auto-immune disease such as the Guillain--Barre syndrome.