Icariin sustains the proliferation and differentiation of Aß25-35-treated hippocampal neural stem cells via the BDNF-TrkB-ERK/Akt signaling pathway.

OBJECTIVES: Icariin (ICA) can be potentially used to treat Alzheimer's disease (AD), but the mechanism was not clear. The current study explored the effects of ICA on hippocampal neural stem cells, aiming to provide a comprehensive basis for its clinical application. METHODS: Hippocampal neural stem cells were isolated from newborn rats and their differentiation ability was evaluated by performing immunofluorescence staining. Next, Aß cell model was constructed by treating the cells with Aß25-35, and then the model was further treated by ICA or shBDNF or the two in combination. The viability and differentiation of the cells were, respectively, analyzed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide (MTT) and flow cytometry. The expression of BDNF-TrkB-ERK/Akt signaling pathway was assessed by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot (WB). RESULTS: The hippocampal neural stem cells can differentiate into neurons and astrocytes. ICA effectively promoted the viability and differentiation of Aß cell models. The expression levels of BDNF and TrkB in Aß cell models were obviously decreased, which were noticeably increased by ICA. Moreover, BDNF knockdown further inhibited the viability and differentiation of Aß model cells, which could be reversed by ICA. BDNF knockdown not only suppressed the expressions of BDNF and TrkB in Aß cell models but also effectively prevented the phosphorylation of ERK/Akt; however, these phenomena were significantly alleviated by ICA treatment. DISCUSSION: ICA promoted the proliferation and differentiation of Aß25-35-treated hippocampal neural stem cells through BDNF-TrkB-ERK/Akt signaling pathway. The current findings might contribute to the treatment of AD.

Antagonizing effect of icaritin on apoptosis and injury of hippocampal neurocytes induced by amyloid beta via GR/BDNF signaling pathway.

Purpose: Amyloid beta is the main component of senile plaques deposited in the hippocampus of people with Alzheimer's disease (AD), with neurotoxicity and pro-apoptotic characteristics. Icaritin (ICA) has been found to have the properties of plerosis, regeneration, and anti-apoptosis in the neurocytes, its effects on Aß-induced hippocampal neurocytes were studied in this research.Methods: Different concentrations of Aß25-35 were used to treat mouse hippocampal neuron HT22 cells to determine the optimal concentration for constructing AD model; different concentrations of ICA were used to pretreat HT22 cells to explore their effects on cell activity. Cell injury was evaluated by measuring the viability and apoptosis of HT22 cells using MTT assay, and Annexin V/PI and Hoechst 33342 staining, respectively. Western blot and qPCR were performed to detect the expressions of glucocorticoid receptor (GR), brain-derived neurotrophic factor (BDNF), and apoptosis-related factors. Oxidative stress was assessed by the biochemical analysis of Lactate dehydrogenase (LDH) release and superoxidase dismutase (SOD) activity.Results: Aß25-35 inhibited the viability of HT22 cells and the expression of GR and BDNF in HT22 cells in a concentration-dependent manner. ICA at 20 µmol/L (ICA20) the most significantly increased the viability of HT22 cells and the expressions of GR and BDNF in HT22 cells. ICA20 increased viability, inhibited apoptosis and LDH release, promoted SOD activity and the expressions of GR, BDNF and Bcl-2, and inhibited the expressions of Bax and C Caspase-3 in AD. More importantly, shRNA-GR reversed the positive effects of ICA20 on AD.Conclusions: ICA protected hippocampal neurocytes against Aß25-35 via GR/BDNF signaling pathway.

Determination of cyantraniliprole and its major metabolite residues in pakchoi and soil using ultra-performance liquid chromatography-tandem mass spectrometry.

A rapid, simple and reliable analytical method was developed for the determination of cyantraniliprole and its major metabolite J9Z38 in pakchoi and soil by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample preparation approach is known as QuEChERS, which stands for quick, easy, cheap, effective, rugged and safe. Samples were extracted with acetonitrile, and cleaned up with dispersive primary and secondary amine sorbent before analysis by UPLC-MS/MS. The limit of quantitation for cyantraniliprole and J9Z38 was 0.01 mg/kg in both pakchoi and soil. Average recoveries of cyantraniliprole and J9Z38 at three fortified levels (0.01, 0.05, 0.1 mg/kg) ranged from 77.8% to 102.5% with relative standard deviation of 1.6%-8.9%. This method has been applied to the analysis of cyantraniliprole and J9Z38 residues in real pakchoi and soil samples selected from field. The results of the residue dynamic experiment showed that the half-life of cyantraniliprole ranged from 2.9 to 6.4 days in pakchoi and 8.7 to 18.2 days in soil, respectively. The final residual levels of cyantraniliprole in pakchoi and soil from Guangdong and Shanghai were below 0.20 and 0.10 mg/kg, respectively; similarly, the final residual levels of J9Z38 in pakchoi and soil from Guangdong and Shanghai were <0.07 and 0.01 mg/kg. These results will be helpful in setting maximum residue limit guidance for cyantraniliprole in pakchoi in China.

[Study on the determination of total nitrogen (TN) in different types of soil by near-infrared spectroscopy (NIS)].

In the present paper, the feasibility of determination of total nitrogen (TN) content in different types of soil based on NIS technology was studied. Some surface and subsurface soil samples were collected from Jiangsu, Henan, Shanxi, Hebei and Jilin province in China, on behalf of paddy, calcareous, loess, coastal alluvial and black soil types separately. After being air-dried, milled and screened, the scanned spectra were obtained by near-infrared spectrometer using the sample with diameter below 1 millimeter, meantime the content of TN was measured with the traditional Kelvin method. A model between TN content and spectrum was established and also it was modified through some spectrum pretreatment using the OPUS software. Then a best model was chosen with root mean squares of crosscheck (RMSECV) being the lowest. Finally the stability and application of the model was discussed through quantitative analysis. The results showed that a good model can be separately established in each province using the surface soil from the same area on behalf of the same soil type, whose RMSECV were within 0.01% on average, and the correlation efficient was above 0.85 basically. The model established using the surface soil can be well used for analysis of TN content in other surface and subsurface soil from the same area whose TN was within the range of the model. The root mean squares of prediction (RMSEP) and correlation efficient of the quantitative analysis were at about 0.01% and 0.80 separately. However, maybe affected by soil types, the model established in one area had certain limitations in the application to other areas even as its TN content was within the range of the model. Whenas, choosing some data from each area randomly to form a new sample group can establish a good new integrated model with RMSECV and correlation efficient being 0.010 2% and 0.985 6 respectively and that can be well used to predict TN content in soil from each area.