Buyang Huanwu decoction increases the expression of glutamate transporter-1 and glutamate synthetase in association with PACAP-38 following focal ischemia

Buyang Huanwu decoction alleviates oxidative injury of cerebral ischemia-reperfusion through PKCε/Nrf2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke is a significant risk factor for human health, and Buyang Huanwu Decoction is a classical and famous Chinese formula for treating it, but without clear pharmacological mechanism.

AIM OF THE STUDY

The aim of this study was to investigate that the molecular mechanism of BYHWD activation of the PKCε/Nrf2 signaling pathway to attenuate cerebral ischemia-reperfusion (I/R) oxidative damage.

MATERIALS AND METHODS

The MCAO method was used to establish a brain I/R injury model in SD rats, and neurological deficits were evaluated by neurological function score. Neuronal damage was observed by Nissl staining and immunofluorescence detection of MAP2 expression. Oxidative damage was observed by ROS, SOD, GSH-PX, MDA, and 8-OHdG. Changes in mitochondrial membrane potential were detected by using the fluorescent probe JC-1. The Western blot analysis detected protein expression of PKCε, P-PKCε, total Nrf2, nuclear Nrf2, HO-1, and NQO1.

RESULTS

BYHWD significantly enhanced neural function, reduced neuronal damage, inhibited the production of ROS, decreased MDA and 8-OHdG levels, increased SOD and GSH-PX activity to reduce oxidative damage, and restored mitochondrial membrane potential. BYHWD and Nrf2 activator TBHQ increased total Nrf2, nucleus Nrf2 protein expression, and its downstream HO-1 and NQO1 proteins, and the administration of the Nrf2 inhibitor brusatol reduced the enhancing effect of BYHWD. Meanwhile, BYHWD increased the expression of PKCε and P-PKCε and the administration of the PKCε inhibitor εV1-2 reduced the effect of BYHWD in increasing the expression of PKCε, P-PKCε, nuclear Nrf2, and HO-1, as well as promoting the effect of Nrf2 translocation to the nucleus.

CONCLUSION

This study marks the first to demonstrate that BYHWD ameliorates oxidative damage and attenuates brain I/R injury by activating the PKCε/Nrf2/HO-1 pathway.

Pituitary Adenylate Cyclase-Activating Polypeptide: A Promising Neuroprotective Peptide in Stroke

The search for viable, effective treatments for acute stroke continues to be a global priority due to the high mortality and morbidity. Current therapeutic treatments have limited effects, making the search for new treatments imperative. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a well-established cytoprotective neuropeptide that participates in diverse neural physiological and pathological activities, such as neuronal proliferation, differentiation, and migration, as well as neuroprotection. It is considered a promising treatment in numerous neurological diseases. Thus, PACAP bears potential as a new therapeutic strategy for stroke treatment. Herein, we provide an overview pertaining to the current knowledge of PACAP, its receptors, and its potential neuroprotective role in the setting of stroke, as well as various mechanisms of neuroprotection involving ionic homeostasis, excitotoxicity, cell edema, oxidative stress, inflammation, and cell death, as well as the route of PACAP administration.

Understanding the multi-herbal composition of Buyang Huanwu Decoction: A review for better clinical use

ETHNOPHARMACOLOGICAL RELEVANCE

Buyang Huanwu Decoction (BHD) is a multi-herbal composition commonly prescribed in the treatment of cerebrovascular diseases such as stroke. Although studies have been conducted at the cellular (in vitro), animal and human (in vivo) level, there was no detailed analysis on how the composition and proportion of BHD is modified according to target diseases.

AIM OF STUDY

The purpose of this study is to investigate the composition and proportion of each herb in BHD to summarize how the original BHD was modified according to the target disease.

MATERIALS AND METHODS

Electronic literature searches were performed in three databases, collecting sixty-eight studies for the final analysis. The studies were divided into three types: cell studies, animal experiments and clinical trial. In the analysis, the decoction formula including the composition and the weight proportion of the herbs in BHD used in the studies and the target diseases were examined.

RESULTS

The result showed that in cell studies, the targets were mostly cell differentiation, cell injury and immune activation. In animal studies, cerebrovascular diseases such as cerebral ischemia were the most identified target diseases followed by nervous system and cardiovascular diseases. While the proportions of the herbs in BHD used in these studies were in general similar to the original formula, some studies reduced the amount of Astragali Radix to half of the original amount. Modified BHDs were used in four studies for cerebrovascular and peripheral nerve diseases. However, no significant correlation has been observed between the target diseases and the change of the proportion of the herbs in BHD.

CONCLUSIONS

The most commonly used formula was the original composition of BHD, and modified BHDs were reported to be used to treat cerebrovascular and nervous diseases. Further studies about the effects of BHD by composition and proportion of herbs are needed in the future.

Buyang Huanwu Decoction () Attenuates Glial Scar by Downregulating the Expression of Leukemia Inhibitory Factor in Intracerebral Hemorrhagic Rats

OBJECTIVE

To evaluate the effect of Buyang Huanwu Decoction (, BYHWD) on glial scar after intracerebral hemorrhage (ICH) and investigate the underlying mechanism.

METHODS

Collagenase type VII (0.5 U) was injected stereotaxically into right globus pallidus to induce ICH model. One hundred and twenty Sprague-Dawley rats were randomly divided into 3 groups according to a random number table, including normal group (n=40), ICH model group (n=40) and BYHWD group (n=40), respectively. After ICH, the rats in the BYHWD group were intragastrically administered with BYHWD (4.36 g/kg) once a day for 21 days, while the rats in ICH group were administered with equal volume of distilled water for 21 days, respectively. Double immunolabeling was performed for proliferating cell nuclear antigen (PCNA)⁺/glial fibrillary acidic protein (GFAP)⁺ nuclei. The expression of GFAP and leukemia inhibitory factor (LIF) was evaluated by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The astrocytes with hypertrophied morphology around the hematoma was observed on day 3 after ICH. The number of GFAP positive cells and GFAP mRNA levels increased notably on day 3 and reached the peak on day 14 post-ICH (P<0.01). PCNA+/GFAP+ nuclei were observed around the hematoma and reached the peak on day 14 post-ICH (P<0.01). In addition, LIF-positive astrocytes and LIF mRNA level in the hemorrhagic region increased significantly till day 14 post-ICH (P<0.01). However, BYHWD not only reduced the number of PCNA⁺/GFAP⁺ nuclei, but also decreased GFAP and LIF levels (P<0.05).

CONCLUSIONS

BYHWD could attenuate ICH-induced glial scar by downregulating the expression of LIF in the rats.

Upregulation of glutamate metabolism by BYHWD in cultured astrocytes following oxygen-glucose deprivation/reoxygenation in part depends on the activation of p38 MAPK

Recent studies have demonstrated that Buyang Huanwu Decoction (BYHWD) decreased glutamate levels subsequent to cerebral ischemia. Glutamate transporter-1 (GLT-1) and glutamine synthetase (GS), which are located in astrocytes, mainly contribute to glutamate transportation, thus reducing glutamate concentration. BYHWD has previously been demonstrated to upregulate GLT-1 and GS following ischemia in vivo. However, whether BYHWD can directly influence astrocytic GLT-1/GS levels remains unknown. In the present study, the effect of BYHWD containing serum (BYHWD-CS) on GLT-1/GS levels in astrocytes following oxygen-glucose deprivation/reoxygenation (OGD/R) was investigated. The results revealed that BYHWD-CS enhanced the expression levels of GLT-1 and GS in cultured astrocytes, which reduced glutamate concentration in the culture medium. Meanwhile, increased p38 mitogen-activated protein kinase (p38 MAPK) was phosphorylated (activation form) by BYHWD-CS in cultured astrocytes, and the specific p38 inhibitor SB203580 blocked the increase of GLT-1/GS accompanied by decreased cell viability. Furthermore, SB203580 suppressed the effect of BYHWD-CS on the level of glial fibrillary acidic protein (an astrocytic marker), thus confirming that astrocytes are directly involved in the protective role of BYHWD after OGD/R. These findings suggest that BYHWD upregulates GLT-1 and GS via p38 MAPK activation, and protects cultured astrocytes from death caused by OGD/R (typical in vitro model), which complemented the role of astrocytes in the protective effect of BYHWD.