Effects of a traditional Chinese medicine, Qing Nao Yi Zhi Fang, on glutamate excitotoxicity in rat fetal cerebral neuronal cells in primary culture

Traditional Chinese medicine in treating ischemic stroke by modulating mitochondria: A comprehensive overview of experimental studies

Ischemic stroke has been a prominent focus of scientific investigation owing to its high prevalence, complex pathogenesis, and difficulties in treatment. Mitochondria play an important role in cellular energy homeostasis and are involved in neuronal death following ischemic stroke. Hence, maintaining mitochondrial function is critical for neuronal survival and neurological improvement in ischemic stroke, and mitochondria are key therapeutic targets in cerebral stroke research. With the benefits of high efficacy, low cost, and high safety, traditional Chinese medicine (TCM) has great advantages in preventing and treating ischemic stroke. Accumulating studies have explored the effect of TCM in preventing and treating ischemic stroke from the perspective of regulating mitochondrial structure and function. In this review, we discuss the molecular mechanisms by which mitochondria are involved in ischemic stroke. Furthermore, we summarized the current advances in TCM in preventing and treating ischemic stroke by modulating mitochondria. We aimed to provide a new perspective and enlightenment for TCM in the prevention and treatment of ischemic stroke by modulating mitochondria.

Advances in diagnosis, treatments, and molecular mechanistic studies of traumatic brain injury

Traumatic brain injury (TBI) is a main cause of death and disability around the world especially in soldiers, children, and young men. Since its clinical diagnosis and treatment cannot predict its prognosis, novel diagnostic techniques need to be developed, insight into its molecular mechanisms needs to be gleaned, and alternative and complementary medicine (ACM) approaches to its treatment need to be developed. This review summarizes the new diagnostic methods used in clinical practice, such as imaging of structural abnormalities after TBI and measurement of prognosis-related biomarkers. This review also describes the cellular mechanisms of traditional Chinese medicine in terms of intracellular signaling pathways, the extracellular microenvironment, and stem cells. This review concludes by describing experimental and clinical studies of the use of traditional Chinese medicine as a form of ACM to treat TBI. This review helps to understand advances in the field of TBI diagnosis and treatment.

Liuwei Dihuang decoction facilitates the induction of long-term potentiation (LTP) in senescence accelerated mouse/prone 8 (SAMP8) hippocampal slices by inhibiting voltage-dependent calcium channels (VDCCs) and promoting N-methyl-d-aspartate receptor (NMDA) receptors

ETHNOPHARMACOLOGICAL RELEVANCE

Liuwei Dihuang decoction (LW) is a typical traditional Chinese medicine (TCM) prescription and consists of six herbs including Rehmannia glutinosa Libosch. (family: Scrophulariaceae), Cornus officinalis Sieb. (family: Cornaceae), Dioscorea opposite Thunb. (family: Dioscoreaceae), Alisma orientale (G. Samuelsson) Juz (family: Alismataceae), Poria cocos (Schw.)Wolf (family: Polyporaceae) and Paeonia suffruticosa Andrews (family: Paeoniaceae). It has long been used clinically in treatment of many kinds of diseases with the sign of Yin insufficiency of kidney.

AIM OF THE STUDY

Our previous pharmacological studies demonstrated that LW possesses effect of ameliorating the decline of the learning and memory in senescence accelerated mouse/prone 8 (SAMP8), but the mechanism has not been well established. LW-containing serum (LWCS) is used in the current study to elucidate the possible mechanisms.

MATERIALS AND METHODS

6-month-old SAMP8 was used in this study to investigate the effect of LWCS on the induction of long-term potentiation (LTP). Primary cultured hippocampal neurons were used in this study to investigate the effects of LWCS on [Ca(2+)](i), I(Ca) and N-Methyl-d-aspartate (NMDA)-evoked currents. [Ca(2+)](i) was imaged using Fluo-3 and whole-cell patch recordings were applied to study the I(Ca) and NMDA-evoked currents.

RESULTS

We find that LWCS facilitates the induction of LTP in hippocampal slices of 6-month-old SAMP8. In primary cultured hippocampal neurons, LWCS increases intracellular [Ca(2+)](i), the I(Ca) is suppressed by LWCS, and NMDA-evoked currents are promoted.

CONCLUSION

These results indicate that LW improves the synaptic plasticity by inhibiting voltage-dependent calciumchannels (VDCCs) and promoting the function of NMDA receptors. This improvement might be one of the mechanisms contributing to cognitive improvement effect of LW.

Puerarin attenuates glutamate-induced neurofilament axonal transport impairment

AIM OF THE STUDY

Puerarin (Pur) is a primary component of the most functional extracts of Pueraria lobata used in traditional Chinese medicine for centuries. Since it has been postulated that Pur protects the brain against glutamate (Glu) neurotoxicity, we investigated the effects of Pur on Glu-induced axonal transport impairment in primary hippocampal neurons in this study.

MATERIALS AND METHODS

Primary hippocampal cultures were prepared from 2-day-old Sprague-Dawley rats. Intracellular calcium concentration [Ca(2+)](i), neurofilament (NF) phosphorylation and protein kinase activity for Cdk5 were measured. Time-lapse imaging technology was used to capture the NF axonal transport in the cultured neurons with transiently transfected fluorescence protein linked to the N-terminus of NF-M (EGFP-NFM).

RESULTS

The results showed that Pur significantly diminished the Glu-induced elevation of [Ca(2+)](i) in dose-dependent manner and antagonized the Glu-evoked increases in NF phosphorylation at protein levels. The neurons under the Glu treatment displayed the accumulation of immobile NF clusters in the cell body and the reduced rates of axonal transport of NFs by 72.8% compared to the control neurons. Intriguingly, Pur reversed the slowed rate of the axonal transport by 35.6%. Pur also remarkably attenuated Glu-evoked activation of Cdk5.

CONCLUSIONS

Pur may play a role in protecting against Glu-induced NF axonal transport impairment in rat primary hippocampal neurons by inhibiting the increased [Ca(2+)](i) and by impeding the activation of Cdk5.

Achyranthes bidentata Blume extract protects cultured hippocampal neurons against glutamate-induced neurotoxicity

We have prepared an aqueous extract of Achyranthes bidentata Blume, a Chinese medicinal herb commonly prescribed for arthritis treatment or immnopotentiation, and have found that Achyranthes bidentata extract promotes nerve growth and prevents neuronal apoptosis.

AIM OF THE STUDY

To investigate the protective effect of Achyranthes bidentata extract against glutamate-induced neurotoxicity in primary culture of rat hippocampal neurons.

MATERIALS AND METHODS

We accomplished MTT assay for cell viability, Hoechst 33342 staining, and flow cytometry for cell apoptosis analysis to examine the effects of Achyranthes bidentata extract on glutamate-induced neurotoxicity, and also used Fluo 4-AM measurement, RT-PCR and Western blot analysis to determine the changes in intracellular calcium concentration [Ca(2+)](I), and mRNA and protein levels of Bcl-2, respectively, concurrently accompanied with the influences of Achyranthes bidentata extract.

RESULTS

Achyranthes bidentata extract was found to inhibit glutamate-induced neuronal damage in a dose- and time-dependent manner. On the other hand, Achyranthes bidentata extract depressed glutamate-induced elevation of intracellular calcium concentration [Ca(2+)](i), and also antagonized glutamate-evoked decreases in Bcl-2 expression at mRNA and protein levels.

CONCLUSION

The results suggest that Achyranthes bidentata extract prevents glutamate-induced cell damage in primarily cultured hippocampal neurons by inhibiting an increase in [Ca(2+)](i), and reversing the down-regulation of Bcl-2.

Effects of Liuwei Dihuang decoction on ion channels and synaptic transmission in cultured hippocampal neuron of rat

The effect of Liuwei Dihuang decoction (LW), a traditional Chinese medicine (TCM) prescription, on voltage-dependent currents and synaptic transmission were investigated in cultured hippocampal neurons of rat by whole-cell patch clamp recording technique. After application with serum from LW-treated rats, termed LW-containing serum (LWCS) for 48 h, the amplitude of delay rectifying K+ current (IK) and voltage-gated Ca2+ current (ICa) decreased. While the frequency of spontaneous excitatory post-synaptic current (sEPSC) and miniature excitatory post-synaptic current (mEPSC) increased significantly. Yet the amplitude of voltage-depended Na+ current (INa) and transient outward K+ current (IA), membrane capacitance and resistance remained unchanged. The results indicated that LWCS possessed the effect of modulating or improving neuronal and synaptic function, which possibly contribute to the cognition enhancing effect of LW.

The diverse effects of a Chinese medicine, Qing Nao Yi Zhi Fang, on the proliferation of human arterial smooth muscle cells and endothelial cells

Qing Nao Yi Zhi Fang (QNYZ), a Chinese medicine, has been developed as a drug for the prevention and treatment of vascular dementia. We examined the effects of QNYZ-treated serum and QNYZ on the proliferation of human arterial smooth muscle cells (SMCs) and endothelial cells (ECs). SMCs did not grow in a medium containing 10% QNYZ serum. QNYZ also completely inhibited the proliferation of SMCs at higher concentrations (500-1000 microg/ml), although no detectable inhibitory activity on the SMC proliferation was observed at lower concentrations (100-200 microg/ml). In contrast, QNYZ (250-500 microg/ml) significantly stimulated the proliferation of ECs and prostacyclin production in ECs. These results suggest that QNYZ may have suppressive effects on the development of intimal thickening in atherosclerosis and after arterial wall injury.

Protective effects of Danshensu from the aqueous extract of Salvia miltiorrhiza (Danshen) against homocysteine-induced endothelial dysfunction

Homocysteine (Hcy) is a by-product of methionine metabolism. An imbalance of Hcy in the body may lead to hyperhomocysteinemia, a condition with elevated Hcy concentration in blood that may be one of the risk factors responsible for the development of several vascular diseases (thromboembolism, atherosclerosis, stroke, vascular diseases and dementia). Radix Salvia miltiorrhiza (Danshen), a well-known Chinese medicinal herb that can activate and improve blood microcirculation, is noticeable for its beneficial effect in treating cardiovascular diseases. The present study is to demonstrate the protective effect of Danshen extract against the homocysteine-induced adverse effect on human umbilical vein endothelial cell (HUVEC). Homocysteine (5 mM) not only decreased the cell viability but also caused the disruption of capillary-like structure formation in vitro. The protective effect of Danshen aqueous extract and its active compounds on endothelial cell function were demonstrated through an in vitro tube formation assay, which mimics the new blood vessel formation. To identify the active components in the aqueous extract of Danshen, the content was characterized by instrumental analysis using high performance liquid chromatography with diode array detector (DAD) and electrospray tandem mass spectrometry (ESI-MS/MS). Interestingly, Danshen extract and its pure compounds showed different effectiveness in protecting HUVEC against Hcy-induced injury according to the following descending order: Danshen aqueous extract, 3-(3,4-dihydroxy-phenyl)-2-hydroxy-propionic acid (Danshensu), protocatechuic acid, catechin and protocatechualdehyde. We believed that such findings might provide evidence in understanding the beneficial effects of Danshen on the cardiovascular system.

Neurotoxicity of amphetamine derivatives is mediated by caspase pathway activation in rat cerebellar granule cells

The neurotoxic action of the abuse drugs methamphetamine (METH) and 3,4-methylenedioxymethamphetamine (MDMA) on cerebellar granule neurones (CGNs) culture was examined. Treatment for 48 h with METH or MDMA (1-5 mM) induced a higher decrease in viability than 24 h treatment. z.VAD.fmk (100 microM) but not MK-801 nor NBQX recovered control viability values. In both cases, cell death was characterised as apoptotic rather than necrotic by morphology cell observation. Apoptosis measured by flow cytometry indicated an increase in the hypodiploid population after 48 h treatment with METH and MDMA. Apoptosis was reverted by the presence of z.VAD.fmk (100 microM) but not by 10 microM MK-801 or NBQX. Similar results were obtained by analysing nuclear chromatine condensation. These results ruled out excitotoxic participation in amphetamine derivative-induced neurotoxicity in CGNs. Participation of radical oxygen species (ROS) was evaluated using alpha-tocopherol (1-15 microM) and cytometric studies. The co-treatment with 4 mM METH or MDMA for 48 h partially reverted neurotoxic action and apoptotic features, indicating ROS implication in CGNs death by amphetamine derivatives. Alteration of mitochondrial function induced cytochrome C (Cyt C) release after 48-h treatment with METH and MDMA (4 mM). There was also indication of caspase-3-like activation, measured by immunoanalysis and biochemically. Finally, neurodegenerative action caused by amphetamine derivatives may be prevented by using caspase inhibitors.

Neuroprotective effect of Alpinia oxyphylla Miq. fruits against glutamate-induced apoptosis in cortical neurons

The protective effect of ethanol extract from the fruits of Alpinia oxyphylla on glutamate-induced neuronal apoptosis was examined in primary cultured mouse cortical neurons. After exposure of cortical neurons to 30 microM glutamate for 24 h, cortical neurons exhibited remarkable apoptotic-like death as evidenced by multi-indices including morphological features, cell viability assay, DNA fragmentation on agarose gel and flow cytometric analysis. Co-treatment of the neurons with A. oxyphylla fruits extract (AFEx) (80-200 microg/ml) in the presence of glutamate significantly elevated cell viability, reduced the number of apoptotic cells and decreased the intensity of glutamate-induced DNA fragmentation. These results suggest the neuroprotective potential of A. oxyphylla fruits against glutamate-induced neuronal apoptosis.