Puerarin attenuates glutamate-induced neurofilament axonal transport impairment

Mechanism of aquaporin 4 (AQP 4) up-regulation in rat cerebral edema under hypobaric hypoxia and the preventative effect of puerarin

AIM

We aim to investigate the mechanism of aquaporin 4 (AQP 4) up-regulation during high-altitude cerebral edema (HACE) in rats under hypobaric hypoxia and preventative effect of puerarin.

METHODS

Rats were exposed to a hypobaric chamber with or without the preventative treatment of puerarin or dexamethasone. Morriz water maze was used to evaluate the spatial memory injury. HE staining and W/D ratio were used to evaluate edema injury. Rat astrocytes and microglia were co-cultured under the condition of hypoxia with the administration of p38 inhibitor, NF-κB inhibitor or puerarin. Interleukin 6 (IL-6) and tumor necrosis factor α (TNF α) of cortex and culture supernatant were measured with ELISA. AQP4, phosphorylation of MAPKs, NF-κB pathway of cortex and astrocytes were measured by Western blot.

KEY FINDINGS

Weakened spatial memory and cerebral edema were observed after hypobaric hypoxia exposure. AQP4, phosphorylation of NF-κB and MAPK signal pathway of cortex increased after hypoxia exposure and decreased with preventative treatment of puerarin. Hypoxia increased TNF-α and IL-6 levels in cortex and microglia and puerarin could prevent the increase of them. AQP4 of astrocytes increased after co-cultured with microglia when both were exposed to hypoxia. AQP4 showed a decrease after administered with p38 inhibitor, NF-κB inhibitor or puerarin.

SIGNIFICANCE

Hypoxia triggers inflammatory response, during which AQP4 of astrocytes can be up regulated through the release of TNF-α and IL-6 from microglia. Puerarin can exert a preventative effect on the increase of AQP4 through inhibiting the release of TNF-α and phosphorylation of NF-κB, MAPK pathway.

Puerarin Ameliorates D-Galactose Induced Enhanced Hippocampal Neurogenesis and Tau Hyperphosphorylation in Rat Brain

Enhanced neurogenesis has been reported in the hippocampus of patients with Alzheimer's disease (AD), the most common neurodegenerative disorder characterized with amyloid-β (Aβ) aggregation, tau hyperphosphorylation, and progressive neuronal loss. Previously we reported that tau phosphorylation played an essential role in adult hippocampal neurogenesis, and activation of glycogen synthase kinase (GSK-3), a crucial tau kinase, could induce increased hippocampal neurogenesis. In the present study, we found that treatment of D-galactose rats with Puerarin could significantly improve behavioral performance and ameliorate the enhanced neurogenesis and microtubule-associated protein tau hyperphosphorylation in the hippocampus of D-galactose rat brains. FGF-2/GSK-3 signaling pathway might be involved in the effects of Puerarin on hippocampal neurogenesis and tau hyperphosphorylation. Our finding provides primary in vivo evidence that Puerarin can attenuate AD-like enhanced hippocampal neurogenesis and tau hyperphosphorylation. Our finding also suggests Puerarin can be served as a treatment for age-related neurodegenerative disorders, such as AD.

Protective effects of puerarin on acute lung and cerebrum injury induced by hypobaric hypoxia via the regulation of aquaporin (AQP) via NF-κB signaling pathway

OBJECTIVE

Hypobaric hypoxia, frequently encountered at high altitude, may lead to lung and cerebrum injury. Our study aimed to investigate whether puerarin could exert ameliorative effects on rats exposed to hypobaric hypoxia via regulation of aquaporin (AQP) and NF-κB signaling pathway in lung and cerebrum.

MATERIALS AND METHODS

40 Sprague Dawley rats were divided into four groups (normal control group, hypobaric hypoxia group, puerarin group and dexamethasone group). Wet/dry ratio, blood gas, pathological changes of lung and cerebrum and spatial memory were observed in each group. Inflammatory cytokines in bronchoalveolar lavage fluid (BALF) were determined with ELISA and expression of AQP1, AQP4, NF-κB signaling pathway in lung and cerebrum with western blot RESULTS: Puerarin showed significant preventative effects on tissue injury and behavioral changes, as evidenced by histopathological findings and Morris water maze. In addition, levels of inflammatory cytokines in BALF decreased in the two preventative groups compared with those of hypobaric hypoxia group. AQP in lung and cerebrum increased under the condition of hypobaric hypoxia while was down regulated in both two preventative groups. NF-κB and IκB was also inhibited by puerarin.

CONCLUSION

Our study suggested that lung and cerebrum injury, increased inflammatory cytokines in BALF and increased AQP1, AQP4 and NF-κB signaling pathway occurred under the condition of hypobaric hypoxia. Moreover, puerarin could prevent lung and cerebrum injury of rats exposed to hypobaric hypoxia via down-regulation of inflammatory cytokines, AQP1 and AQP4 expression and NF-κB signaling pathway.

Puerarin attenuates smoke inhalation injury by regulation of Th1/Th2 expression and inhibition of Th17 cells in rats

OBJECTIVE

Puerarin, a kind of traditional Chinese medicine, possesses immunomodulatory property. However, the immunomodulatory effects of puerarin on smoke inhalation injury have not been determined. The aim of the current study was to investigate the therapeutic efficacy of puerarin on gunpowder smog-induced acute lung injury in rats via regulation of Th1/Th2/Th17 expression.

MATERIALS AND METHODS

Wistar rats were equally randomized to four groups (normal control group, puerarin control group, smoke inhalation injury group, puerarin treatment plus smoke inhalation injury group). The severity of lung injury was evaluated by histopathology, myeloperoxidase (MPO) activity in lung homogenates, cell counting in bronchoalveolar lavage fluid (BALF), and lung vascular permeability parameters including lung wet to dry weight ratio and protein concentration in BALF. Flow cytometry was used to analyze the expression of Th1/Th2/Th17 lymphocytes in blood of rats.

RESULTS

Puerarin showed significant therapeutic effects against neutrophil infiltration and tissue injury, as evidenced by histopathological findings and MPO activity. Lung vascular permeability was also relieved by puerarin administration. Additionally, puerarin significantly decreased the number of neutrophils and lymphocytes in BALF compared with smoke inhalation injury group. Furthermore, puerarin increased Th1 immunity and reduced Th2 and Th17 responses and thereby altering the Th1/Th2/Th17 imbalance induced by smoke inhalation.

CONCLUSIONS

Our findings suggested that puerarin suppressed inflammatory responses in gunpowder smog-induced acute lung injury by regulation of Th1/Th2/Th17 expression, and may be a potential therapeutic agent for smoke inhalation injury.

Protective effects of edaravone combined puerarin on inhalation lung injury induced by black gunpowder smog

OBJECTIVE

The present study aimed to investigate the combined effects of puerarin with edaravone on inhalation lung injury induced by black gunpowder smog.

MATERIALS AND METHODS

Male Wistar rats were divided into five groups (control group, edaravone group, puerarin group, edaravone combined with puerarin group and inhalation group). The severity of pulmonary injuries was evaluated after inducing acute lung injury. Arterial blood gas, inflammatory cytokines, biochemical, parameters, cell counting, W/D weight ratio and histopathology were analyzed. Results in lung tissues, either edaravone or puerarin treatment alone showed significant protective effects against neutrophil infiltration and tissue injury, as demonstrated by myeloperoxidase activity and histopathological analysis (all p<0.05). In addition, combined treatment with both edaravone and puerarin demonstrated additive protective effects on smog-induced lung injury, compared with single treatment.

CONCLUSIONS

Combination of edaravone and puerarin shows promise as a new treatment option for acute lung injury/acute respiratory distress syndrome patients.

Progress on the pharmacological research of puerarin: a review

Contemporary pharmacological research has demonstrated that puerarin, the most important phytoestrogen extracted from Pueraria lobata(Willd.) Ohwi, has protecting functions on the cardiovascular system, nervous system, osteoporosis, liver injury, and inflammation in vivo and in vitro. Most of these research studies focused on inhibiting oxidative stress and apoptosis through regulating various bioactivators and signal pathways. Among these, superoxide dismutase (SOD), endothelial nitric oxide synthase (eNOS) and malondialdehyde (MDA), and PI3K/Akt, MAPK, and NF-κB are of great importance. The data cited in this review were mainly obtained from articles listed in PubMed and Elsevier SDOL published from 1959 to 2013, and the search term used was "puerarin".

The anti-apoptotic and anti-inflammatory properties of puerarin attenuate 3-nitropropionic-acid induced neurotoxicity in rats

Puerarin (Pur), an isoflavonoid extracted from the dried roots of Pueraria lobata, has been reported to be useful in the treatment of various diseases. This study was designed to evaluate the anti-apoptotic and anti-inflammatory activities of Pur against 3-nitropropionic acid (3-NP) induced neurotoxicity. For 5 consecutive days, male Wistar rats were given Pur (200 mg/kg body mass) 30 min before treatment with 20 mg/kg body mass of 3-NP. The striata, hippocampi, and cortices of the 3-NP treated group showed apoptotic damage, inflammation, and energy deficit as well as histopathological lesions. The 3-NP-induced alteration in apoptotic biomarkers (caspase-3 activity/level, cytosolic cytochrome c, Bax/Bcl-2 levels) were significantly ameliorated by Pur treatment. Moreover, Pur pretreatment blocked 3-NP-induced inflammatory biomarkers (NF-κB, TNF-α, and iNOS) and prevented the energy deficit (ATP reduction). Nissl staining further confirmed Pur's neuroprotective effect. These results indicate that Pur may be a useful preventive approach to various neurodegenerative diseases with underlying apoptosis and neuroinflammation.

Puerarin attenuates ovalbumin-induced lung inflammation and hemostatic unbalance in rat asthma model

Aim. We aimed to investigate and evaluate the preventive activity of puerarin on the ovalbumin-induced asthma rat model. Materials and Methods. Male Wistar rats were sensitized intraperitoneally on days 0, 7, and 14 and challenged to ovalbumin intratracheally on day 21. Groups of sensitized rats were treated randomly either with placebo, puerarin, dexamethasone, or puerarin combined with dexamethasone, from days 15 to 20. Inflammatory markers, including cell counts in bronchoalveolar lavage fluid (BALF), inflammatory cytokines, histopathology, and coagulation parameters, such as coagulation tests and the activity of coagulation factors, were analyzed. Results. Puerarin significantly inhibited the recruitment of inflammatory cells in BALF and lung tissue. At the same time, the release of IL-4, IL-10, and IFN-γ in serum and the expression of mRNAs in lung tissue homogenate were changed by puerarin. Administration of puerarin also effectively rectified the coagulation disorder in asthmatic rats, such as prothrombin time (PT) (P < 0.01), thrombin time (TT) (P < 0.05), fibrinogen (FIB) (P < 0.01),the activity of factor II (FII) (P < 0.01), the activity of factor V (FV) (P < 0.05), the activity of factor VII (FVII) (P < 0.05), the activity of factor X (FX) (P < 0.05), the activity of factor VIII (FVIII) (P < 0.01), the activity of factor IX (FIX) (P < 0.05), and the activity of factor XII (FXII) (P < 0.05). Conclusions. Our results provide a clue that puerarin was useful for the preventive of allergic airway disease in rodents.

Puerarin: a review of pharmacological effects

Puerarin is the major bioactive ingredient isolated from the root of the Pueraria lobata (Willd.) Ohwi, which is well known as Gegen (Chinese name) in traditional Chinese medicine. As the most abundant secondary metabolite, puerarin was isolated from Gegen in the late 1950s. Since then, its pharmacological properties have been extensively investigated. It is available in common foods and is used in alternative medicine. It has been widely used in the treatment of cardiovascular and cerebrovascular diseases, diabetes and diabetic complications, osteonecrosis, Parkinson's disease, Alzheimer's disease, endometriosis, and cancer. The beneficial effects of puerarin on the various medicinal purposes may be due to its wide spectrum of pharmacological properties such as vasodilation, cardioprotection, neuroprotection, antioxidant, anticancer, antiinflammation, alleviating pain, promoting bone formation, inhibiting alcohol intake, and attenuating insulin resistance. However, the direct molecular mechanisms and targets remain unclear. This review provides a comprehensive summary of the pharmacological effects of puerarin.

Puerarin Accelerates Peripheral Nerve Regeneration

This study investigates the effect of puerarin (PR) on peripheral nerve regeneration in vitro and in vivo. PR at concentrations of 1, 10, and 100 μM significantly promoted survival and outgrowth of cultured Schwann cells, as compared to the controls treated with culture medium only. in vivo study, peripheral nerve regeneration was evaluated across a 15-mm gap in the sciatic nerve of rats using a silicone rubber nerve chamber filled with PR solution. The control group chambers were filled with normal saline only. At the end of eight weeks, animals in the PR groups, especially at a concentration of 1 μM, had a significantly higher density of myelinated axons, greater evoked action potential area, and a larger nerve conductive velocity, as compared to the controls. All experimental results indicate that PR treatment promotes nerve growth and is a promising herbal medicine for recovery of regenerating peripheral nerves.

ALS genetic modifiers that increase survival of SOD1 mice and are suitable for therapeutic development

Amyotrophic lateral sclerosis (ALS) is a frequently fatal motor neuron disease without any cure. To find molecular therapeutic targets, several studies crossed transgenic ALS murine models with animals transgenic for some ALS target genes. We aimed to revise the new discoveries and new works in this field. We selected the 10 most promising genes, according to their capability when down-regulated or up-regulated in ALS animal models, for increasing life span and mitigating disease progression: XBP-1, NogoA and NogoB, dynein, heavy and medium neurofilament, NOX1 and NOX2, MLC-mIGF-1, NSE-VEGF, and MMP-9. Interestingly, some crucial modifier genes have been described as being involved in common pathways, the most significant of which are inflammation and cytoskeletal activities. The endoplasmic reticulum also seems to play an important role in ALS pathogenesis, as it is involved in different selected gene pathways. In addition, these genes have evident links to each other, introducing the hypothesis of a single unknown, common pathway involving all of these identified genes and others to be discovered.

Kudzu root: traditional uses and potential medicinal benefits in diabetes and cardiovascular diseases

Kudzu root (Gegen in Chinese) is the dried root of Pueraria lobata (Willd.) Ohwi, a semi-woody, perennial and leguminous vine native to South East Asia. It is often used interchangeably in traditional Chinese medicine with thomson kudzu root (Fengen in Chinese), the dried root of P. thomsonii, although the Chinese Pharmacopoeia has separated them into two monographs since the 2005 edition. For more than 2000 years, kudzu root has been used as a herbal medicine for the treatment of fever, acute dysentery, diarrhoea, diabetes and cardiovascular diseases. Both English and Chinese literatures on the traditional applications, phytochemistry, pharmacological activities, toxicology, quality control and potential interactions with conventional drugs of both species have been included in the present review. Over seventy phytochemicals have been identified in kudzu root, with isoflavonoids and triterpenoids as the major constituents. Isoflavonoids, in particular puerarin, have been used in most of the pharmacological studies. Animal and cellular studies have provided support for the traditional uses of kudzu root on cardiovascular, cerebrovascular and endocrine systems, including diabetes and its complications. Further studies to define the active phytochemical compositions, quality standards and clinical efficacy are warranted. Strong interdisciplinary collaboration to bridge the gap between traditional medicine and modern biomedical medicine is therefore needed for the development of kudzu root as an effective medicine for the management of diabetes and cardiovascular diseases.