Combination of electrical stimulation and bFGF synergistically promote neuronal differentiation of neural stem cells and neurite extension to construct 3D engineered neural tissue.

OBJECTIVE: The construction of in vitro three-dimensional (3D) neural tissue has to overcome two main types of challenges: (1) How to obtain enough number of functional neurons from stem cells in 3D culture; (2) How to wire those lately developed neurons into functional neural networks. Here, we describe the potential of using direct current (DC) electric field (EF) together with basic fibroblast growth factor (bFGF) synergistically in promoting neural stem cell (NSC) neuronal differentiation following by directing neurite outgrowth in the 3D neural tissue construction. APPROACH: By adjusting the electrical stimulation setup in this study, long-term electrical stimulation could be present in vitro. At an EF strength of 150 mV mm-1, cell responses, including cell viability, neuronal differentiation, cell morphology, the length of neuronal processes, synaptic structure and neural network formation, were quantified and analyzed. MAIN RESULTS: Analysis revealed that NSCs showed no significant cell death after certain EF treatments. EF-stimulated NSCs in 3D Matrigel mainly differentiated into neurons, but unlike NSCs in two-dimensional conditions, their processes were flat and stunted. When combined with bFGF, EF stimulation provided appropriate bioactive cues to establish engineered neural tissue with a proper neuronal cell number, highly branched neurites, and a well-developed neuronal network. SIGNIFICANCE: It is for the first time the synergistic effects of EF and bFGF stimulation have been evaluated in inducing the differentiation of NSCs into neurons and the acquisition of long neurites in a culture environment of in vitro 3D model. These optimized conditions may allow a well-developed neuronal network to be established within hydrogel droplets.

Development and validation of an UHPLC-MS/MS approach for simultaneous quantification of five bioactive saponins in rat plasma: Application to a comparative pharmacokinetic study of aqueous extracts of raw and salt-processed Achyranthes bidentata.

A simple, accurate and sensitive ultra high-performance liquid chromatography-tandem mass spectrometry approach was established for the simultaneous determination of ß-ecdysterone, 25S-inokosterone, ginsenoside Ro, chikusetsusaponin IV and chikusetsusaponin IVa in rat plasma after oral administration of raw and salt-processed Achyranthes bidentata extract. The saponins were completely separated on a Waters BEH C18 UHPLC column by using acetonitrile/0.1% formic acid-water as mobile phases. The mass analysis was performed in a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) with negative scan mode. The sample preparations for protein removal were accomplished using a simple acetonitrile precipitation method. The calibration curves displayed good linearity (r2 > 0.9998) with the concentration ranges of 24.4-6100 ng mL-1, 25.6-6400 ng mL-1, 20.4-8500 ng mL-1, 21.6-5400 ng mL-1, 21.6-6100 ng mL-1 for the five saponins, respectively. The intra-day and inter-day precisions (RSD) of the five saponins were less than 3.95% and the bias of the accuracies ranged from -4.50% to 4.84%. The extraction recoveries of the five saponins ranged from 95.2% to 104.8% and the matrix effects were satisfactory. In comparison with the raw group, the parameters of Cmax and AUC0-t of ß-ecdysterone, 25S-inokosterone, ginsenoside Ro, and chikusetsusaponin IVa elevated remarkably (p < 0.05) after oral delivery of the extract of salt-processed Achyranthes bidentata, which revealed that salt-processing could increase bioavailability of ß-ecdysterone, 25S-inokosterone, ginsenoside Ro and chikusetsusaponin IVa.

Integrating UHPLC-MS/MS quantification and DAS analysis to investigate the effects of wine-processing on the tissue distributions of bioactive constituents of herbs in rats: Exemplarily shown for Dipsacus asper.

Wine-processing, which is sauteing with rice wine, will change the inclination and direction of herbs' actions. After being wine-processed, the effects of nourishing liver and kidney of Dipsacus asper will be strengthened. However, the underlying mechanism remains elusive. The following study is to establish and validate an UHPLC-MS/MS approach to determine six bioactive constituents in tissue samples, including loganin, loganic acid, chlorogenic acid, 3,5-dicaffeoylquinic acid, 4-caffeoylquinic acid and asperosaponin VI and apply the approach to a comparative tissue distribution study of raw and wine-processed Dipsacus asper in rats. A Shimadzu UHPLC system coupled with triple quadrupole mass spectrometer was employed for analysis of the six analytes using multiple reaction monitoring (MRM) mode. A one-step protein precipitation by methanol was employed to extract the six analytes from tissues. Chloramphenicol and glycyrrhetinic acid were selected as internal standards. The proposed approach was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery. Our results revealed that all of the calibration curves displayed good linear regression (r2>0.9991). Intra- and inter-assay variability for all analytes ranged from -4.62 to 4.93% and from -4.98 to 4.92%, respectively. The recovery rates for each analytes were determined to be 88.3-100.1%. All the samples showed satisfactory precision and accuracy after various stability tests, including storage at 25°C for 4h, -80°C for 30days, three-freeze-thaw cycles, and 4°C for 24h. Tissue pharmacokinetic parameters including AUC0-t, t1/2, Tmax and Cmax were calculated. Collectively, the parameters of Cmax and AUC0-t of the six analytes in wine-processed group were remarkably elevated (p<0.05) in the rat liver and kidney as compared with those of the raw group. But in the rat heart and spleen, the Cmax and AUC0-t of asperosaponin VI was decreased as compared with those of the raw group. The accumulation of bioactive constituents in liver and kidney tissues after wine-processing will contribute to the enhancement of liver and kidney nourishing effects.

UHPLC-MS/MS quantification combined with chemometrics for the comparative analysis of different batches of raw and wine-processed Dipsacus asper.

A rapid and sensitive ultra-high performance liquid chromatography with tandem mass spectrometry approach was established for the simultaneous determination of 4-caffeoylquinic acid, loganic acid, chlorogenic acid, loganin, 3,5-dicaffeoylquinic acid, dipsacoside B, asperosaponin VI, and sweroside in raw and wine-processed Dipsacus asper. Chloramphenicol and glycyrrhetinic acid were employed as internal standards. The proposed approach was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery. Intra- and interassay variability for all analytes were 2.8-4.9 and 1.7-4.8%, respectively. The standard addition method determined recovery rates for each analytes (96.8-104.6%). In addition, the developed approach was applied to 20 batches of raw and wine-processed samples of Dipsacus asper. Principle component analysis and partial least squares-discriminate analysis revealed a clear separation between the raw group and wine-processed group. After wine-processing, the contents of loganic acid, chlorogenic acid, dipsacoside B, and asperosaponin VI were upregulated, while the contents of 3,5-dicaffeoylquinic acid, 4-caffeoylquinic acid, loganin, and sweroside were downregulated. Our results demonstrated that ultra-high performance liquid chromatography with tandem mass spectrometry quantification combined with chemometrics is a viable method for quality evaluation of the raw Dipsacus asper and its wine-processed products.