Effect of oxymatrine on apoptosis of hippocampal neurons by p38/JNK signaling pathway / 中国中药杂志

To investigate the effect and mechanism of oxymatrine(OMT) on hippocampal neurons apoptosis. Effect of OMT on survival of hippocampal neurons was measured by MTT.Effect of OMT on LPS-induced lactate dehydrogenase(LDH) release rate in hippocampal neurons was measured by biochemical methods. Hoechst 33342 staining was used to observe the apoptotic morphology of hippocampal neurons.The mRNA expression levels of Bax, Bcl-2, and Caspase-3 were detected by Real-time quantitative PCR(RT-qPCR), and the protein expression levels of p38, p-p38, JNK, p-JNK, Bax, Bcl-2 and Caspase-3 were detected by Western blot.The results showed that, hippocampal neurons all grew well after treatment by different doses (0.37-6.0 g•L⁻¹) of OMT for 24 h. Stimulation from LPS increased the release of LDH(P<0.01), improved the JNK and p38 phosphorylation levels(P<0.01), increased the proportion of Bax/Bcl-2 and the expression of Caspase-3(P<0.01), and promoted the apoptosis of hippocampal neurons. OMT pretreatment could significantly reduce the release of LDH induced by LPS stimulation(P<0.05 or P<0.01), reduce the p38 and JNK phosphorylation, decrease the expression of Caspase-3 and Bax/Bcl-2(P<0.01), and diminish the apoptosis of hippocampal neurons.In conclusion, OMT could reduce the LPS-induced phosphorylation of p38 and JNK, down-regulate the Bax/Bcl-2 ratio and expression of Caspase-3, thus inhibiting apoptosis of hippocampal neurons. The mechanism may be associated with p38/JNK signaling pathway.

The role of the TLR4/NF-κB signaling pathway in Aβ accumulation in primary hippocampal neurons / 生理学报

The present study aimed to investigate the role of the Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) signaling pathway in the accumulation of amyloid β protein (Aβ) in primary hippocampal neurons of rats. The purity of these cultured neurons was determined by using immunofluorescence techniques. Lipopolysaccharide (LPS, a TLR4 ligand) or CLI-095 (a TLR4 inhibitor) was used to activate or inhibit TLR4 signaling, respectively. Pyrrolidine dithiocarbamate (PDTC), on the other hand, was used to inhibit NF-κB, a downstream effector of the TLR4 signaling pathway. The contents of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and Aβ1-42 in the supernatant were assessed by enzyme-linked immunosorbent assay (ELISA). The mRNA levels of TNF-α, IL-1β, a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10), β-site APP cleaving enzyme 1 (BACE-1), Presenilin-1 (PS-1), and β-amyloid precursor protein (β-APP) were examined by real-time quantitative PCR (RT-qPCR). The protein levels of ADAM10, BACE-1, PS-1 and β-APP were examined by Western blotting. Meanwhile, the levels of TLR4 mRNA and protein in hippocampal neurons were tested by RT-qPCR and Western blotting, respectively, after stimulation with Aβ1-42 at different concentrations. We observed that the purity of cultured hippocampal neurons after being cultured for 7 days was above 95%. Compared with untreated neurons, LPS-treated neurons showed higher expression levels of TNF-α, IL-1β, BACE-1, PS-1, β-APP, and Aβ1-42, but a lower expression level of ADAM10. These effects were reversed upon pre-treatment with CLI-095 or PDTC. Furthermore, TLR4 expression was upregulated in the presence of Aβ1-42. Taken together, these results provide evidence that elevation in the level of inflammatory cytokines accompanies the activation of TLR4 signaling, and that the consequent downregulation of ADAM10 and upregulation of BACE-1/PS-1 are likely responsible for the accumulation of β-APP and Aβ, which in turn increases TLR4 level to create a positive feedback loop that may constitute the basis for the progression of Alzheimer's disease.

The role of Toll-like receptor 4 on inflammation and Aβ formation in cortex astrocytes / 生理学报

To investigate the role and possible molecular mechanism of astrocytes in inflammation and amyloid β-protein (Aβ) formation, in this research, by using LPS to stimulate cultured rat astrocytes in vitro with or without anti-Toll-like receptor 4 (TLR4) antibody pretreatment, we first detected the TLR4, TNF-α, IL-1β, β-amyloid precursor protein (β-APP) and β-site APP clearing enzyme 1 (BACE1) mRNA with real-time PCR, and TLR4, NF-κB/P65 protein in cultured astrocytes by Western blot, and then further probed the translocation of NF-κB/P65 using immunofluorescence and the contents of TNF-α, IL-1β and Aβ in culture supernatant through ELISA. We found that all of these indexes increased at different degrees after LPS-stimulation. However, if pretreatment with anti- TLR4 antibody, such stimulating effects of LPS on the nuclear translocation of NF-κB/P65 and TNF-α, IL-1β, Aβ contents in astrocytic culture supernatant were reduced significantly or disappeared in comparison with the group with only LPS-administration. Our results suggest that TLR4 in astrocytes might play an important role in the inflammation and Aβ formation through the TLR4/NF-κB signaling pathway, thus providing new knowledge and understanding of the inflammatory hypothesis of AD pathogenesis.

Involvement of Toll-like receptor 4 in apoptosis of hippocampal neurons through Akt/FoxO3a/Bim signaling pathways / 生理学报

The present study was to investigate whether Toll-like receptor 4 (TLR4)-mediated Akt/FoxO3a/Bim signaling pathway participated in lipopolysaccharide (LPS)-induced apoptosis in hippocampal neurons. The primarily cultured rat hippocampal neurons were treated with LPS, TLR4 antibody+LPS, and LY294002+LPS, respectively. Cell vitality was assayed by CCK-8. Expressions of p-Akt, Akt, p-FoxO3a, FoxO3a, Bim and active-Caspase-3 of each group were detected by Western blot analysis; the mRNA expression of Bim was detected by real-time quantitative PCR; FoxO3a nuclear translocation was detected by fluorescence microscope. The rate of cell apoptosis was assayed by flow cytometry. The results showed that cell vitality of hippocampal neurons decreased after being treated with LPS in a time-dependent way. Compared with the control group, the expressions of p-Akt and p-FoxO3a decreased significantly, FoxO3a translocated into the nucleus, meanwhile, the expression of Bim and active-Caspase-3, and the apoptotic ratio of hippocampal neurons increased in LPS treated neurons. Pretreatment with TLR4 antibody significantly blocked, while PI3K antagonist LY294002 further strengthened these changes induced by LPS. In conclusion, the present study suggests that Akt/FoxO3a/Bim signaling pathways mediated by TLR4 participate in the apoptotic processes of primarily cultured hippocampal neurons treated with LPS, and the activation of TLR4 causes neuronal apoptosis.

The role of TLR4-mediated MyD88-dependent pathway in neuroinflammation in hippocampal neurons of rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate weather there is a toll-like receptor 4 (TLR4)-mediated myeloid differentiation factor 88 (MyD88)-dependent pathway in hippocampal neurons of rats and the probable role of the pathway in neuroinflammation.</p><p><b>METHODS</b>To establish the proper model, primarily cultured hippocampal neurons were treated with lipopolysaccharides (LPS), or pretreated with TLR4 antibody then co-treated with LPS. The expression of mRNA of MyD88 and TNF-alpha receptor associated factor 6 (TRAF6) were tested by RT-qPCR. The content of MyD88 and TRAF6 were tested by Western blot. The nuclear translocation of nuclear factor-kappaB/P65 (NF-kappaB/p65) was tested by immunofluorescence. The content of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and nitric oxide (NO) were tested by ELISA.</p><p><b>RESULTS</b>LPS could increase MyD88 and TRAF6 mRNA, upregulate protein level of MyD88 and TRAF6 and increase the level of TNF-alpha, IL-1beta and NO in cell culture supernatant. LPS also could promote NF-kappa B/p65 translation to the nucleus. The pretreatment with TLR4 antibody reduced the translocation to nucleus for NF-kappaB/P65 and the contents of TNF-alpha, IL-1beta and NO in the culture supernatant.</p><p><b>CONCLUSION</b>There is a TLR4-mediated MyD88-dependent pathway in hippocampal neurons. The activation of this pathway can increase the level of TNF-alpha, IL-1beta and NO in cell culture supernatant. TLR4-mediated MyD88-dependent pathway in hippocampal neurons participate in neuroinflammation, that means neurons are not passive in inflammation.</p>

The effect of meloxicam on the inflammatory reaction induced by beta amyloid protein in Alzheimer's disease rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effect and mechanism of meloxicam on the inflammatory reaction induced by beta amyloid protein (AB) in Alzheimer's disease (AD) rats.</p><p><b>METHODS</b>The rat model was established by microinjection of Abeta(1-40) into hippocampus. The expression of NF-kappaB p65 and glial fibrillary acidic protein (GFAP) in hippocampus were detected by immunohistochemistry. The content of GFAP in cortex was tested by Western-blot. The content of TNF-alpha in cortex was tested by ELISA. The expression of IL-1beta mRNA was tested by RT-PCR.</p><p><b>RESULTS</b>The expression of NF-kappaB p65, GFAP and TNF-alpha as well as IL-1beta mRNA were decreased by meloxicam.</p><p><b>CONCLUSION</b>Meloxicam can reduce the proliferation of astrocyte by decreasing the expression of GFAP in AD model rat's hippocampus and cortex. And the depression of NF-kappaB p65 may significantly decrease the expression of TNF-alpha1 and IL-1beta to lessen the inflammatory reaction in cerebral tissue.</p>

Protective effect of Naoyikang on the Alzheimer's disease model mice induced by D-galactose and NaNO2 / 中国应用生理学杂志

<p><b>AIM</b>To investigate the mechanisms of Naoyikang (Traditional Chinese Medicine) on the Alzheimer's Disease (AD) model mice induced by D-galactose (D-gal) and NaNO2.</p><p><b>METHODS</b>The mouse model was established by intraperitoneal injection of D-gal and NaNO2. The capacity of learning and memory was tested on mice with electrical maze; the content of nitric oxide (NO) and the activity of monoamine oxidase-B (MAO-B), glutathione peroxidase (GSH-PX), Na(+) -K(+) -ATP enzyme and Ca(2+) -ATP enzyme in cerebral cortex and hippocampus were assayed by biochemical methods; expression of Bax and Bcl-2 mRNA was detested by RT-PCR.</p><p><b>RESULTS</b>Naoyikang could ameliorate the capacity of learning and memory of AD model mice and reduce MAO-B activity in the brain tissue and activate the activity of Na(+) -K(+) -ATP enzyme and Ca(2+) -ATP enzyme in the brain tissue and decrease the expression of Bax mRNA, but increase the expression of Bcl-2 mRNA in the model brain tissue.</p><p><b>CONCLUSION</b>Naoyikang could protect AD model mice induced by D-gal and NaNO2. It could modify the metabolism of monoamine neurotransmitter in brain through reducing MAO-B activity and protect neurons by activating the activity of Na(+) -K(+) -ATP enzyme and Ca(2+) -ATP enzyme and decrease Bax expression and increase Bcl-2 expression in the model brain tissue.</p>

Effects of Chinese herb compound Naoyikang on expression of choline acetyltransferase in brain of rats with Alzheimer's disease / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effects of Naoyikang (NYK) on expression of choline acetyltransferase (ChAT) in brain of rats with Alzheimer' s disease (AD).</p><p><b>METHOD</b>Bilateral infusions of Ibotenic acid (IBO) into nucleus basalis of Meynert (NBM) using hamilton syringe and stereotaxic apparatus were adopted to establish the rat model of AD. After intragastrically administrated with different solution for 28 days, immunohistochemistry and Western-blot were adopted to study the expression of ChAT in frontal cortex of AD rats.</p><p><b>RESULT</b>NYK could improve the morphology and increase the number of ChAT immunoreactive neurons, and significantly promote ChAT protein expression.</p><p><b>CONCLUSION</b>NYK may be able to increase the synthesis of acetylcholine (ACh) through elevating the expression of ChAT protein, thus improving the level of brain ACh so as to protect central cholinergic neurons.</p>

Effect of acupoint-injection of oxymatrine on experimental hepatic carcinoma and study on the mechanism / 中国针灸

<p><b>OBJECTIVE</b>To investigate the effect of acupoint injection of oxymatrine (OM) on experimental hepatocellular carcinoma and the mechanism.</p><p><b>METHODS</b>The rats of hepatocellular carcinoma induced by 2-acetoaminoflurence (2-AAF) were randomly divided into a normal control group (group N), a model group (group M), a control group of oxymatrine intraperitoneal injection (OM ip group) and a treatment group of small dose oxymatrine injection into Zusanli (OM ZSL group). At the end of 12h week, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (gamma-GT) were determined. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expressions of cyclin D1 and cyclin-dependent kinase 4 (CDK4) mRNA in hepatocellular carcinoma tissues.</p><p><b>RESULTS</b>The number of cancer nodes on the surface of liver in th Om ip group and the Om ZSL group was lower than in the group M, with the serum ALT, AST, and gamma-GT levels significantly decreased (P<0. 01), and significantly inhibited expressions of cyclin D1, CDK4 mRNA (P<0. 01).</p><p><b>CONCLUSION</b>OM ip and small dose oxymatrine injection into ZSL can treat or delay hepatocarcinogenisis of hepatocellular carcinoma induced by 2-AAF. Partial mechanism of this anti-carcinoma is protecting hepatocytes possibly through improving hepatic functions, and inhibiting excessive proliferation of liver cancer cells via inhibiting the expressions of cyclin Dl, CDK4 mRNA.</p>

Protective effect of Naoyikang on the damage induced by glutamate in hippocampal neuron / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effect of Naoyikang serum on the damage induced by glutamate in hippocampal neuron.</p><p><b>METHODS</b>Morphological observation, MTT assay and nuclear DNA-associated fluorescence with DAPI dye were applied to evaluate the viability of hippocampal neuron, immunocytochemistry and RT-PCR were used to determine the expression of PTEN.</p><p><b>RESULTS</b>A decreased viability and increased expression of PTEN were shown in hippocampal neuron in response to the treatment with glutamate. It was shown that the percentage of cell death and the expression of PTEN were reduced by the treatment with Naoyikang serum.</p><p><b>CONCLUSION</b>These results suggest that Naoyikang may prevent the toxicity of glutamate by suppressing the expression of PTEN.</p>