Ganoderma lucidum extract ameliorates MPTP-induced parkinsonism and protects dopaminergic neurons from oxidative stress via regulating mitochondrial function, autophagy, and apoptosis.

Neuroprotection targeting mitochondrial dysfunction has been proposed as an important therapeutic strategy for Parkinson's disease. Ganoderma lucidum (GL) has emerged as a novel agent that protects neurons from oxidative stress. However, the detailed mechanisms underlying GL-induced neuroprotection have not been documented. In this study, we investigated the neuroprotective effects of GL extract (GLE) and the underlying mechanisms in the classic MPTP(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced mouse model of PD. Mice were injected with MPTP to induce parkinsonism. Then the mice were administered GLE (400 mg kg-1 d-1, ig) for 4 weeks. We observed that GLE administration significantly improved locomotor performance and increased tyrosine hydroxylase expression in the substantia nigra pars compact (SNpc) of MPTP-treated mice. In in vitro study, treatment of neuroblastoma neuro-2a cells with 1-methyl-4-phenylpyridinium (MPP+, 1 mmol/L) caused mitochondrial membrane potential collapse, radical oxygen species accumulation, and ATP depletion. Application of GLE (800 µg/mL) protected neuroblastoma neuro-2a cells against MPP+ insult. Application of GLE also improved mitochondrial movement dysfunction in cultured primary mesencephalic neurons. In addition, GLE counteracted the decline in NIX (also called BNIP3L) expression and increase in the LC3-II/LC3-I ratio evoked by MPP+. Moreover, GLE reactivated MPP+-inhibited AMPK, mTOR, and ULK1. Similarly, GLE was sufficient to counteract MPP+-induced inhibition of PINK1 and Parkin expression. GLE suppressed MPP+-induced cytochrome C release and activation of caspase-3 and caspase-9. In summary, our results provide evidence that GLE ameliorates parkinsonism pathology via regulating mitochondrial function, autophagy, and apoptosis, which may involve the activation of both the AMPK/mTOR and PINK1/Parkin signaling pathway.

Protective effects of octacosanol on 6-hydroxydopamine-induced Parkinsonism in rats via regulation of ProNGF and NGF signaling.

AIM: To investigate the protective effects of octacosanol in 6-hydroxydopamine-induced Parkinsonian rats and find whether octacosanol has effects on pro nerve growth factor (pro-NGF), NGF and the downstream effector proteins. METHODS: Behavioral tests, enzymatic assay, tyrosine hydroxylase immunohistochemistry, TUNEL and Western blot were used to investigate the effects of octacosanol in this rat model of PD. RESULTS: Oral administration of octacosanol (35-70 mg/kg, po for 14 d) significantly improved the behavioral impairments in rats induced by 6-OHDA and dose-dependently preserved the free radical scavenging capability of the striatum. Octacosanol treatment also effectively ameliorated morphological appearances of TH-positive neuronal cells in nigrostriatal systems and decreased the apoptotic cells induced by 6-OHDA in striatum. In addition, octacosanol strikingly blocked the 6-OHDA-induced increased expression of proNGF-p75NTR-sortilin death signaling complex and its downstream effector proteins. Meantime, octacosanol prevented the decreased levels of NGF, its receptors TrkA and p-Akt which together mediated the cell survival pathway. CONCLUSION: The findings implicated that the anti-parkinsonism effects afforded by octacosanol might be mediated by its neuro-microenvironment improving potency through retrieving the ratios of proNGF:NGF and the respective receptors p75NTR:TrkA in vivo. Due to its excellent tolerability and non-toxicity, octacosanol may be a promising agent for PD treatment.

[Relationship of oxidative DNA damage and expression of mitochondrial apoptotic proteins in rat striatum induced by 6-hydroxydopamine].

OBJECTIVE: To study the relationship between oxidative DNA damage and mitochondrial apoptosis relative proteins in rat striatum induced by 6-hydroxydopamine (6-OHDA) during the pathogenesis of Parkinson's disease (PD). METHODS: 6-OHDA was stereotactically injected into the bilateral right striatum of rats to produce PD models. Assays for 8-oxo-dG immunohistochemistry and Western blot for MTH1, Cytochrome c, Cl-caspase 9 and Cl-caspase 3 in right striatum was separately conducted. RESULTS: In 10 successful PD rats, compared with either sham or normal group, there were obvious more 8-oxo-dG positive cells in lesioned striatum while there was a lower expression of MTH1. Furthermore, the expressions of such intrinsic apoptotic pathway factors as cytoplasmic Cytochrome c, Cl-caspase 9 and Cl-caspase 3 were highly up-regulated in lesioned striatum. CONCLUSION: Oxidative DNA damage plays a key role in the pathogenesis of PD. Furthermore Cytochrome c, caspase 9 and caspase 3 are involved in the regulation of apoptosis under oxidative DNA damage induced by 6-OHDA.

Gossypium herbaceam extracts attenuate ibotenic acid-induced excitotoxicity in rat hippocampus.

Excitotoxicity is one of the most extensively studied processes of neuronal death and plays an important role in Alzheimer's disease. In the present study, the protective effects of Gossypium herbaceam extracts (GHE) on learning and memory impairment induced by excitatory neurotoxin ibotenic acid were examined in vivo using Morris water maze. Furthermore, neuroprotective effects of GHE were investigated with methods of immunohistochemistry and biochemistry. Our data showed that oral administration with GHE at the doses of 35, 70 and 140 mg/kg exerted an improved effect on the learning and memory impairment in rats induced by intracerebral injection of ibotenic acid. To confirm the precise mechanism of memory improvement by presence of GHE, we further investigated the potential protection on the hippocampus. Our findings suggest that GHE afforded a beneficial inhibition on pro-apoptosis proteins expression following ibotenic acid. Additionally, calcium pump activity and calbindin-D28k expression were dramatically increased after GHE treatment, implicating that the modulation of calcium homeostasis could be involved in the mechanism underlying neuroprotection of GHE against ibotenic acid-induced excitotoxicity. These data suggested that GHE could be a potential agent for preventing or retarding the development or progression of Alzheimer's disease.

Effects of hormone replacement therapy on magnetic resonance imaging of brain parenchyma hyperintensities in postmenopausal women.

AIM: To apply 3.0 magnetic resonance imaging (MRI) to study the effects of long-term, low dose hormone replacement therapy (HRT) on the brain parenchyma of postmenopausal women. METHODS: A total of 155 postmenopausal healthy female medical staff members from Peking Union Medical College Hospital were enrolled. The HRT group was composed of 71 subjects who had been given a low dose of HRT for over 4 years, while 84 women who had never been given HRT were enrolled in the control group. The Mini-Mental State Examination (MMSE) was used to evaluate mental state, and an Enzyme-Linked ImmunoSorbent Assay (ELISA) was used to detect plasma levels of sex hormones. In addition, all participants were subjected to an MRI, including axial T2 weighted imaging (T2WI), fluid-attenuated inversion recovery (FLAIR), T1 weighted imaging (T1WI, oblique coronal, vertical to the hippocampus, slice thickness 3 mm without gaps), and a 3D image of the whole brain. RESULTS: The ELISA showed that the plasma level of estradiol in the HRT group was significantly higher than that in the control group (P<0.05). No differences were observed in the MMSE between the two groups. In participants older than 70 years of age, the number of deep white matter hyperintensities (DWMHs) in the control group was significantly higher than that in the HRT group (P=0.0013); however, in other age subgroups, no statistical differences were observed. Finally, no significant difference in periventricular hyperintensity (PVH) between the two groups was observed. CONCLUSION: We found that a high plasma level of estradiol in postmenopausal women receiving long-term HRT was correlated with the survival of brain parenchyma.Acta Pharmacologica Sinica (2009) 30: 1065-1070; doi: 10.1038/aps.2009.81.

Effects of long-term low-dose hormone replacement therapy on the binding capacity of platelet peripheral-type benzodiazepine receptor in postmenopausal women.

The effects of long-term low-dose hormone replacement therapy (HRT) on the level of hormone in plasma and on the binding capacity of peripheral-type benzodiazepine receptor (PBR) on the platelet membranes were investigated among women. This study was a retrospective and case-controlled study where 64 women using long-term low-dose HRT for over 4 years entered the study and 99 women, age and education matched, were enrolled as control. Plasma hormone level and platelet PBR binding capacity of two groups were analyzed. A significant increase in plasma estradiol level in women using HRT was observed, compared to those in the control group. Meanwhile, women in the HRT group displayed higher platelet PBR binding capacity. Further analysis demonstrated that the binding capacity of platelet PBR was closely related to estradiol plasma level in all subjects. These results suggest that long-term low-dose HRT could relieve the decrease of estradiol level in plasma and PBR binding capacity on platelets in postmenopausal women, alleviate the endocrine imbalance process, and might be beneficial for reducing the risks of some diseases.

Effects of ning shen ling granule and dehydroepiandrosterone on cognitive function in mice undergoing chronic mild stress.

OBJECTIVE: To investigate the changes of spontaneous and cognitive behavior, and cholinergic M receptors in the brain of mice subjected to chronic mild stress (CMS), and to determine the effect of Ning Shen Ling Granule (NSL) and dehydroepiandrosterone (DHEA) on them. METHODS: CMS model mice were established by applying stress every day for 3 consecutive weeks with 7 kinds of unforeseeable stress sources, and they were medicated for 1 week beginning at the 3rd week of modeling. The changes in behavior were determined by Morris Water Maze and spontaneous movement test, and M-receptor binding activity in cerebral cortex, hippocampus and hypothalamus were measured by radioactive ligand assay with 3H-QNB. RESULTS: (1) The spontaneous movement in CMS model mice was significantly reduced, with the latency for searching platform in Morris Water Maze obviously prolonged (P<0.01), and these abnormal changes in behavior were improved in those treated with NSL and DHEA. (2) The binding ability of M-receptor in cerebral cortex and hippocampus of CMS mice was significantly decreased as compared with those in the control group (P<0.05), but could be restored to the normal level after intervention with NSL or DHEA. CONCLUSION: The decline of spontaneous movement and spatial learning and memory ability could be induced in animals by chronic mild stress, and that may be related to the low activity of central cholinergic M-receptors. Both NSL and DHEA could effectively alleviate the above-mentioned changes.

M2 Macrophage Transplantation Ameliorates Cognitive Dysfunction in Amyloid-ß-Treated Rats Through Regulation of Microglial Polarization.

Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly population. Neuroinflammation induced by amyloid-ß (Aß) aggregation is considered to be the critical factor underlying AD pathological mechanisms. Alternatively activated (M2) macrophages/microglia have been reported to have neuroprotective effects in neurodegenerative disease. In this study, we characterized the neuroprotective effects of M2 macrophage transplantation in AD model rats and investigated the underlying mechanisms. Intracerebroventricular injection of Aß1 - 42 to rats was used to model AD and resulted in cognitive impairment, neuronal damage, and inflammatory changes in the brain microenvironment. We observed an increased interferon regulatory factor (IRF) 5/IRF4 ratio, resulting in greater production of classically activated (M1) versus M2 microglia. M2 macrophage transplantation attenuated inflammation in the brain, reversed Aß1 - 42-induced changes in the IRF4-IRF5 ratio, drove endogenous microglial polarization toward the M2 phenotype, and ameliorated cognitive impairment. Nerve growth factor (NGF) treatment reduced the IRF5/IRF4 ratio and induced primary microglial polarization to the M2 phenotype in vitro; these effects were prevented by tyrosine Kinase Receptor A (TrkA) inhibition. M2 macrophage transplantation restored the balance of IRF4-IRF5 by affecting the expression of NGF and inflammatory cytokines in the brains of AD model rats. This drove microglial polarization to the M2 phenotype, promoted termination of neuroinflammation, and resulted in improved cognitive abilities.

Lactulose enhances neuroplasticity to improve cognitive function in early hepatic encephalopathy.

Lactulose is known to improve cognitive function in patients with early hepatic encephalopathy; however, the underlying mechanism remains poorly understood. In the present study, we investigated the behavioral and neurochemical effects of lactulose in a rat model of early hepatic encephalopathy induced by carbon tetrachloride. Immunohistochemistry showed that lactulose treatment promoted neurogenesis and increased the number of neurons and astrocytes in the hippocampus. Moreover, lactulose-treated rats showed shorter escape latencies than model rats in the Morris water maze, indicating that lactulose improved the cognitive impairments caused by hepatic encephalopathy. The present findings suggest that lactulose effectively improves cognitive function by enhancing neuroplasticity in a rat model of early hepatic encephalopathy.

Neuroprotective effects of Aceglutamide on motor function in a rat model of cerebral ischemia and reperfusion.

PURPOSE: To investigate the effect and underlying mechanism of Aceglutamide on motor dysfunction in rats after cerebral ischemia-reperfusion. METHODS: Adult male Sprague-Dawley rats were subjected to 2 h transient middle cerebral artery occlusion (MCAO). Aceglutamide or vehicle was intraperitoneally given to rats at 24 h after reperfusion and lasted for 14 days. Subsequently functional recovery was assessed and number of tyrosine hydroxylase (TH)-positive neurons in substantia nigra (SN) was analyzed. Tumor necrosis factor receptor-associated factor 1(TRAF1), P-Akt and Bcl-2/Bax were determined in mesencephalic tissue by Western blot method. PC12 cells and primary cultured mesencephalic neurons were employed to further investigate the mechanism of Aceglutamide. RESULTS: Aceglutamide treatment improved behavioral functions, reduced the infarction volume, and elevated the number of TH-positive neurons in the SN. Moreover, Aceglutamide significantly attenuated neuronal apoptosis in the SN. Meanwhile Aceglutamide treatment significantly inhibited the expression of TRAF1 and up-regulated the expression of P-Akt and Bcl-2/Bax ratio both in vitro and in vivo. CONCLUSIONS: Aceglutamide ameliorated motor dysfunction and delayed neuronal death in the SN after ischemia, which involved the inhibition of pro-apoptotic factor TRAF1 and activation of Akt/Bcl-2 signaling pathway. These data provided experimental information for applying Aceglutamide to ischemic stroke treatment.

[Effects of 7-oxo-DHEA treatment on the immunoreactivity of BALB/c mice subjected to chronic mild stress].

AIM: To determine whether 7-oxo-dehydroepiandrosterone (7-oxo-DHEA) can reverse the hypoimmunity in BALB/c mice exposed to chronic mild stress. METHODS: A chronic mild stress animal model was established by subjecting BALB/c mice to a stressful regimen arranged in an unpredicted manner for 4 consecutive weeks. Immunological function alternations under chronic mild stress were assessed by lymphocytes proliferative response to mitogens and NK cell lysis activity test. RESULTS: The studies showed the correlation between the state of depression and abnormalities in the immune response, such as a decrease of T lymphocytes proliferative response to Con A and suppression of cytotoxic of NK cell. Meanwhile, significant decrease of T3 and T4 levels was also observed. When stressed mice were daily given 7-oxo-DHEA 15 mg.kg-1, lymphocyte proliferative response and the NK cell activity were significantly enhanced and the decreased levels of T3 and T4 were restored in the stressed mice. CONCLUSION: 7-oxo-DHEA can improve the depressive symptoms and hypoimmunity of BALB/c mice induced by chronic mild stress as its parent DHEA.

Propofol may protect PC12 cells from ß-amyloid25₋35 induced apoptosis through the GSK-3ß signaling pathway.

BACKGROUND: There are two major pathological hallmarks of Alzheimer's disease. One is the progressive accumulation of beta-amyloid (Aß) in the form of senile plaques; the other is hyperphosphorylated tau, causing neuronal apoptosis. Some inhalation anesthetics, such as isoflurane and desflurane, have been suggested to induce Aß accumulation and cause AD-like neuropathogenesis. Whether intravenous anesthetics have similar effects is still unclear. We therefore set out to determine the relationship between propofol and AD-like pathogenesis. METHODS: PC12 cells were cultured in serum-free medium for 12 hours prior to drug treatment. Various concentrations from 5 µmol/L to 80 µmol/L of aggregated Aß25-35 were added to determine a proper concentration for further study. After exposure to 10 µmol/L Aß25-35 alone or with 20 µmol/L propofol for 6 hours, PC12 cell viability was determined by MTT assay. Western blotting and immunocytochemical staining were performed to observe the protein expression of the Bcl-2 family, tau phosphorylation at different sites, and tau protein kinases and phosphatases. RESULTS: Aß25-35 induced a decrease in PC12 cell viability in a dose-dependent manner. Exposure to 10 µmol/L Aß25-35 for 6 hours resulted in the mild cell survival, accompanied by a decline in Bcl-2, and an increase in phosphorylation of GSK-3ß and tau at different sites. Compared with the Aß25-35 group, cells treated with propofol alone showed no significant difference, while cells co-incubated with propofol and Aß25-35 showed a significantly higher survival rate (P < 0.01 or P < 0.05). Tau phosphorylation at Ser396, Ser404 and Thr231 and the level of GSK-3ß in PC12 cells increased after exposure to 10 µmol/L Aß25-35. Co-incubation with propofol attenuated cellular apoptosis by inhibiting tau phosphorylation. CONCLUSIONS: These data indicate that propofol may protect PC12 cells from Aß25-35-induced apoptosis and tau hyperphosphorylation through the GSK-3ß pathway, therefore it may be a safer anesthesia for AD and elderly patients.

Gossypium herbaceam L. extracts ameliorate disequilibrium of IL-1RA/IL-1ß ratio to attenuate inflammatory process induced by amyloid ß in rats.

A chronic inflammatory response possibly mediated by Amyloid ß (Aß) is believed to be a major factor in the pathology of Alzheimer's disease (AD). Studies suggest that the mediators of the inflammatory response, which might contribute to brain damage, involve cytokines, such as IL-1ß. IL-1ß could play an important part in the development of pathologic conditions. There is also an endogenous interleukin-1 receptor antagonist (IL-1RA) in IL-1 family, which could prevent the actions of IL-1ß by competing for receptor binding without inducing any signal transduction. Therefore, the balance of IL-1ß vs IL-1RA is a critical parameter in determining not only whether excessive host inflammation will occur, but also the degree of subsequent host cell damage and associated toxicity. In our previous study, it has been determined that the anti-inflammatory action of Gossypium herbaceam L. extracts (GHE) was involved in its neuroprotection. However, the effects of GHE on IL-1ß and IL-1RA have not been clearly defined in the experimental rat model of AD induced by Aß. Therefore, the current study is performed to evaluate whether GHE could affect the disequilibrium of IL-1RA/IL-1ß ratio in the hippocampus of rats after Aß treatment. Subsequently, we further identify that GHE could efficaciously promote Akt and GSK3ß phosphorylation, and thereby contribute to IL-1ß release decrease as well as a concurrent increase in the level of IL-1RA through NF-κB and MAPK pathways. As a consequence, GHE is potentially beneficial to maintain the endogenous IL-1RA/ IL-1ß balance in the hippocampus of rats and it might be a potential agent to ameliorate inflammatory process in AD.

Gene expression profile of amyloid beta protein-injected mouse model for Alzheimer disease.

AIM: To investigate the gene expression profile changes in the cerebral cortex of mice injected icv with amyloid beta-protein (Abeta) fragment 25-35 using cDNA microarray. METHODS: Balb/c mice were randomly divided into a control group and Abeta-treated group. The Morris water maze test was performed to detect the effect of Abeta-injection on the learning and memory of mice. Atlas Mouse 1.2 Expression Arrays containing 1176 genes were used to investigate the gene expression pattern of each group. RESULTS: The gene expression profiles showed that 19 genes including TBX1, NF-kB, AP-1/c-Jun, cadherin, integrin, erb-B2, and FGFR1 were up-regulated after 2 weeks of icv administration of Abeta; while 12 genes were down-regulated, including NGF, glucose phosphate isomerase 1, AT motif binding factor 1, Na+/K+-ATPase, and Akt. CONCLUSIONS: The results provide important leads for pursuing a more complete understanding of the molecular events of Abeta-injection into mice with Alzheimer disease.