Shiping Ma

Curcumin attenuates glutamate neurotoxicity in the hippocampus by suppression of ER stress-associated TXNIP/NLRP3 inflammasome activation in a manner dependent on AMPK.

Curcumin is a natural polyphenolic compound in Curcuma longa with beneficial effects on neuronal protection. This study aims to investigate the action of curcumin in the hippocampus subjected to glutamate neurotoxicity. Glutamate stimulation induced reactive oxygen species (ROS), endoplasmic reticulum stress (ER stress) and TXNIP/NLRP3 inflammasome activation, leading to damage in the hippocampus. Curcumin treatment in the hippocampus or SH-SY5Y cells inhibited IRE1α and PERK phosphorylation with suppression of intracellular ROS production. Curcumin increased AMPK activity and knockdown of AMPKα with specific siRNA abrogated its inhibitory effects on IRE1α and PERK phosphorylation, indicating that AMPK activity was essential for the suppression of ER stress. As a result, curcumin reduced TXNIP expression and inhibited NLRP3 inflammasome activation by downregulation of NLRP3 and cleaved caspase-1 induction, and thus reduced IL-1β secretion. Specific fluorescent probe and flow cytometry analysis showed that curcumin prevented mitochondrial malfunction and protected cell survival from glutamate neurotoxicity. Moreover, oral administration of curcumin reduced brain infarct volume and attenuated neuronal damage in rats subjected to middle cerebral artery occlusion. Immunohistochemistry showed that curcumin inhibited p-IRE1α, p-PERK and NLRP3 expression in hippocampus CA1 region. Together, these results showed that curcumin attenuated glutamate neurotoxicity by inhibiting ER stress-associated TXNIP/NLRP3 inflammasome activation via the regulation of AMPK, and thereby protected the hippocampus from ischemic insult.

Danggui-Shaoyao-San ameliorates cognition deficits and attenuates oxidative stress-related neuronal apoptosis in d-galactose-induced senescent mice

ETHNOPHARMACOLOGICAL RELEVANCE Danggui-Shaoyao-San (DSS), a famous traditional Chinese medicine formula consisting of six herbal medicines, has been used to treat gynecological disorders and neural dysfunctions. AIM OF THE STUDY The present study was carried out to investigate the effects of DSS on cognitive ability and oxidative stress-related neuronal apoptosis in the hippocampus of aging mice induced by d-galactose (d-gal) to elucidate the underlying molecular mechanisms. MATERIALS AND METHODS Ethanol extract of DSS (DE) were orally administered to d-gal-induced senescent mice for six weeks. The cognitive ability was determined by the methods of step-down type passive avoidance test and Morris water maze test. The activities of superoxide dismutase (SOD) and nitric oxide synthase (NOS), and levels of carbonyl protein (CP), glutathione (GSH), malondialdehyde (MDA) and nitric oxide (NO) were also examined. Furthermore, the expression of apoptotic related proteins in hippocampus of d-gal-treated mice, such as Bcl-2, Bax and caspase-3 proteins, were determined by immunohistochemistry. RESULTS DE at the doses of 1.8, 3.6 and 7.2g/kg significantly enhanced the cognitive performances and restored the abnormal activities of SOD and NOS and levels of CP, MDA, GSH and NO induced by d-gal. Moreover, the neural apoptosis in the hippocampus of d-gal-treated mice was improved by DE through regulating the expression of Bcl-2, Bax and caspase-3. CONCLUSION These results demonstrate that DE has neuroprotective effects in d-gal-induced senescent mice by ameliorating oxidative stress induced neuronal apoptosis in the brain.

Curcumin attenuates allergic airway inflammation by regulation of CD4+CD25+ regulatory T cells (Tregs)/Th17 balance in ovalbumin-sensitized mice.

The present study aimed to determine the protective effects and the underlying mechanisms of curcumin on ovalbumin (OVA)-induced allergic inflammation in a mouse model of allergic asthma. Asthma mice model was established by ovalbumin. A total of 60 mice were randomly assigned to six experimental groups: control, model, dexamethasone (2 mg/kg), and curcumin (50 mg/kg, 100 mg/kg, 200 mg/kg). Airway resistance (Raw) was measured by the forced oscillation technique, differential cell count in BAL fluid (BALF) was measured by Wright-Giemsa staining, histological assessment was measured by hematoxylin and eosin (HE) staining, BALF levels of Treg/Th17 cytokines were measured by enzyme-linked immunosorbent assay, Treg cells and Th17 cells were evaluated by flow cytometry (FCM). Our study demonstrated that curcumin inhibited OVA-induced increases in eosinophil count; interleukin (IL)-17A level were recovered in bronchoalveolar lavage fluid increased IL-10 level in bronchoalveolar lavage fluid. Histological studies demonstrated that curcumin substantially inhibited OVA-induced eosinophilia in lung tissue. Flow cytometry (FCM) studies demonstrated that curcumin remarkably inhibited Th17 cells and significantly increased Treg cells. The results in vivo show ovalbumin-induced significantly broke Treg/Th17 balance; curcumin treatments markedly attenuated the inflammatory in asthma model by regulating Treg/Th17 balance. Our findings support the possible use of curcumin as a therapeutic drug for patients with allergic asthma.

Apigenin ameliorates chronic mild stress-induced depressive behavior by inhibiting interleukin-1β production and NLRP3 inflammasome activation in the rat brain

Increasing evidence suggests that inflammation and oxidative stress may contribute to the development of major depressive disorder (MDD). Apigenin, a type of bioflavonoid widely found in citrus fruits, has a number of biological actions including anti-inflammatory and antioxidant effects. Although apigenin has potential antidepressant activity, the mechanisms of this effect remain unclear. The present study aims to investigate the effects of apigenin on behavioral changes and inflammatory responses induced by chronic unpredictable mild stress (CUMS) in rats. GW9662, a selective peroxisome proliferator-activated receptor gamma (PPARγ) inhibitor, was administered 30 min before apigenin. We found that treatment with apigenin (20mg/kg, intragastrically) for three weeks remarkably ameliorated CUMS-induced behavioral abnormalities, such as decreased locomotor activity and reduced sucrose consumption. In response to oxidative stress, the NLRP3 inflammasome was activated and IL-1β secretion increased in the prefrontal cortex (PFC) of CUMS rats. However, apigenin treatment upregulated PPARγ expression and downregulated the expression of NLRP3, which subsequently downregulated the production of IL-1β. In addition, GW9662 diminished the inhibitory effects of apigenin on the NLRP3 inflammasome. In conclusion, our results demonstrate that apigenin exhibits antidepressant-like effects in CUMS rats, possibly by inhibiting IL-1β production and NLRP3 inflammasome expression via the up-regulation of PPARγ expression.

Thymol produces an antidepressant-like effect in a chronic unpredictable mild stress model of depression in mice.

Thymol, a bioactive monoterpene isolated from Thymus vulgaris, has displayed inspiring neuroprotective properties. The present study was designed to evaluate the antidepressant-like effects of thymol on a chronic unpredictable mild stress (CUMS) model of depression in mice and explore the underlying mechanisms. It was observed that thymol treatment (15 mg/kg and 30 mg/kg) significantly reversed the decrease of sucrose consumption, the loss of body weight, the reduction of immobile time in the tail suspension tests (TST) and forced swimming tests (FST) induced by CUMS paradigm. The levels of norepinephrine (NE) and serotonin (5-HT) in the hippocampus decreased in the CUMS-treated mice. Chronic treatments with thymol significantly restored the CUMS-induced alterations of monoamine neurotransmitters in the hippocampus. Our results further demonstrated that thymol administration negatively regulated the induction of proinflammatory cytokines including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α in CUMS mice. Furthermore, thymol inhibited the activation of nod-like receptor protein 3 (NLRP3) inflammasome and its adaptor, and subsequently decreased the expression of caspase-1. In sum, our findings suggested that thymol played a potential antidepressant role in CUMS mice model through up-regulating the levels of central neurotransmitters and inhibiting the expressions of proinflammatory cytokines, which might provide potential for thymol in the light of opening up new therapeutic avenues for depression.

Immunoregulatory effects of glycyrrhizic acid exerts anti-asthmatic effects via modulation of Th1/Th2 cytokines and enhancement of CD4(+)CD25(+)Foxp3+ regulatory T cells in ovalbumin-sensitized mice.

ETHNOPHARMACOLOGICAL RELEVANCE Glycyrrhizic acid (GA) is the main bioactive ingredient of licorice (Glycyrrhiza glabra), and has been found to be associated with multiple therapeutic properties. AIM OF THE STUDY In this study, we investigated immunoregulatory effects of glycyrrhizic acid on anti-asthmatic effects and underlying mechanisms. MATERIALS AND METHODS Asthma model was established by ovalbumin-induced. A total of 60 mice were randomly assigned to six experimental groups: control, model, dexamethasone (2 mg/kg) and GA (10 mg/kg, 20 mg/kg, 40 mg/kg). Airway resistance (Raw) were measured by the forced oscillation technique, histological studies were evaluated by The hematoxylin and eosin (HE) staining, Th1/Th2 and Th17 cytokines were evaluated by enzyme-linked immunosorbent assay (ELISA), and CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) was evaluated by Flow Cytometry (FCM), the forkhead/winged helix transcription factor (Foxp3) was evaluated by western blotting. RESULTS Our study demonstrated that, compared with model group, GA inhibited OVA-induced increases in Raw and eosinophil count; interleukin (IL)-4, IL-5, IL-13 levels were recovered in bronchoalveolar lavage fluid compared; increased IFN-γ level in bronchoalveolar lavage fluid; histological studies demonstrated that GA substantially inhibited OVA-induced eosinophilia in lung tissue and airway tissue compared with model group. Flow cytometry studies demonstrated that GA substantially enhanced Tregs compared with model group. CONCLUSION These findings suggest that GA may effectively ameliorate the progression of asthma and could be used as a therapy for patients with allergic asthma.

Neuroprotective effect of paeonol on cognition deficits of diabetic encephalopathy in streptozotocin-induced diabetic rat

Diabetic encephalopathy (DE) has been characterized by the impaired cognition and the abnormalities of neurochemistry and neurostructure. The study was conducted to evaluate the neuroprotective effect of paeonol on STZ-induced DE rats. Paeonol of 25, 50, 100mg/kg (p.o.) could decrease the latency time and path length, and enhance significantly the spent time in the target quadrant and platform crossings in Morris water maze test. The treatment with paeonol could also increase significantly Na(+)-K(+)-ATP enzyme and ChAT activities, as well as decreasing significantly AchE activity in hippocampal tissue. Immunohistochemistry and TUNEL staining showed that paeonol could attenuate apoptosis of neurons and caspase 3 expression, improve two neurotrophic factors BDNF and IGF expressions, and also ameliorate Aβ deposition in the hippocampus and cerebral cortex. In conclusion, the present study demonstrated diabetic rats treated with paeonol could ameliorate the cognition deficits. These findings indicated paeonol might act as a beneficial agent for the prevention and treatment of DE.

Asiaticoside: attenuation of neurotoxicity induced by MPTP in a rat model of Parkinsonism via maintaining redox balance and up-regulating the ratio of Bcl-2/Bax.

In this study, we investigated the neuroprotective effects of asiaticoside, a triterpenoid saponin isolated from the Chinese medicinal herb Centella asiatica, in the rats model of Parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Rats were first injected with MPTP. One day after surgery, asiaticoside was administered and the behavioral tests were assessed. On 14th day, the rats were sacrificed, substantia nigra (SN) and striatum were dissected, and then dopamine (DA) and its metabolites in striatum and malonyldialdehyde (MDA) contents, reduced glutathione (GSH) level and gene expression level in SN were estimated. Treatment with asiaticoside was found to protect dopaminergic neuron by antagonizing MPTP induced neurotoxicity and to improve locomotor dysfunction. Asiaticoside significantly attenuated the MPTP-induced reduction of dopamine in the striatum. The content of MDA was significantly decreased while the GSH level was significantly increased in asiaticoside-treated groups. In addition, asiaticoside increased the Bcl-2/Bax ratio. These results indicated that asiaticoside was effective in reversing MPTP induced Parkinsonism via its neuroprotective effects including antioxidant activity, maintaining the metabolic balance of DA, and increasing ratio of Bcl-2/Bax.

Effects of perillaldehyde on alternations in serum cytokines and depressive-like behavior in mice after lipopolysaccharide administration.

Perillaldehyde (PAH), a major component of essential oil of Perilla Frutescens, has antidepressant-like effects and anti-inflammatory effects. The present study was designed to determine whether PAH is effective in treating lipopolysaccharide (LPS)-induced depression-like behavior in mice and to explore the possible mechanism between its antidepressant-like effect and anti-inflammatory activity. PAH (60 and 120 mg/kg) and fluoxetine (20mg/kg) were administered intragastrically once daily for 7 consecutive days. In the 7th day, LPS (0.5mg/kg) was injected intraperitoneally 30 min after drug administration. Blood samples were collected 90 min after LPS injection to evaluate serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels by enzyme-linked immunosorbent assay (ELISA). Behavioral tests were measured 24h after LPS injection. After the behavioral tests the prefrontal cortex was rapidly dissected from the brain of the sacrificed mice, then the 5-hydroxytryptamine (5-HT) and norepinephrine (NE) levels in prefrontal cortex were determined by HPLC-MS, and IL-6 and TNF-α mRNA expression was measured using quantitative real-time PCR. Our results showed that a single administration of LPS significantly increased the levels of TNF-α and IL-6 in both the serum and the prefrontal cortex and decreased 5-HT and NE levels in the prefrontal cortex in mice. Pretreatment with fluoxetine (20mg/kg) or PAH (60 and 120 mg/kg) could effectively reverse the alterations in the concentrations of 5-HT and NE, and attenuate LPS-induced increases in TNF-α and IL-6 levels. Besides, LPS administration increased the immobility time in tail suspension test (TST) and forced swimming test (FST) without affecting spontaneous locomotor activity. Fluoxetine (20mg/kg) or PAH (60 and 120 mg/kg) significantly shortened LPS-induced increases of immobility time in both TST and FST. In conclusion, PAH exhibited significant antidepressant-like effects in mice with LPS-induced depression. The antidepressant activity of PAH might be related to the alteration of monoaminergic responses and the anti-inflammatory effects.

Neuroprotective effects of madecassoside in early stage of Parkinson's disease induced by MPTP in rats.

In this study, we investigated the neuroprotective effects of madecassoside, isolated from the Chinese medicinal herb Centella asiatica, in the rat model of early phase of parkinsonism. During intragastric administrations of madecassoside for 7 days, the rats were injected with MPTP on the 7th day. And for the following 14 days, madecassoside were also administered. On the 14th day, the behavioral tests were assessed after 1h of administration. And then, the rats were sacrificed, substantia nigra and striatum were dissected. The content of DA, MDA, GSH, and Bcl-2/Bax gene expression levels and BDNF protein level was determined. Treatment with madecassoside was found to improve locomotor dysfunction and to protect dopaminergic neuron by antagonizing MPTP induced neurotoxicity. Madecassoside significantly attenuated the MPTP-induced reduction of dopamine in the striatum. The MDA contents were significantly decreased while the GSH levels, Bcl-2/Bax ratio and protein expression of BDNF were significantly increased in madecassoside treated groups. These results indicated that madecassoside was effective in recovering MPTP-induced early signs of parkinsonism via its neuroprotective effects including reversing the depletion of DA, antioxidant activity, increasing ratio of Bcl-2/Bax, increasing protein expression of BDNF.