Neuroprotective Effect of Astragalus Polysacharin on Streptozotocin (STZ)-Induced Diabetic Rats

Chemical Composition and Therapeutic Effects of Several Astragalus Species (Fabaceae)

The review integrates information on the component composition and biological activity of some Astragalus L. (Fabaceae) species from studies reported over the past 5-7 years. The aerial and underground parts of 34 Astragalus species contain triterpene saponins, flavonoids, polysacharides, tannins, free organic acids, higher fatty acids, vitamins, trace elements, and other constituents. Among the Astragalus species, A. membranaceus (Fisch.) Bunge is the best studied in terms of component composition and biological activity. Anti-inflammatory, immunomodulatory, antioxidant, anticancer, cardioprotective, and hepathoprotective activities have been experimentally detected in total bioactive substances, fractions, and individual compounds extracted from various parts of A. membranaceus and A. membranaceus var. mongholicus in vitro and in vivo. The composition and biological effects of other Astragalus species are still poorly understood. The review summarizes the recent advances in studying new compounds extracted from Astragalus species and their biological activities.

Angiotensin II Type 1 receptor blockade attenuates the neuropathological changes in the spinal cords of diabetic rats with modulation of nuclear factor erythroid 2-related factor 2/ heme oxygenase 1 system

Peripheral and central neuropathies frequently complicate worldwide diabetes. Compared to peripheral neuropathy, central neuropathy didn`t gain a major research interest. Angiotensin II is reported to be involved in diabetic neuropathic pain but its role in the central pathological changes in the spinal cord is not clear. Here, we study the role of Losartan; an Angiotensin II receptor 1 (AT1) antagonist in suppression of the diabetes-induced changes in the spinal cord. Three groups of rats were applied; a negative control group, a streptozotocin (STZ) diabetic group, and a group receiving STZ and Losartan. After two months, the pathological alteration in the spinal cord was investigated, and an immunohistochemical study was performed for neuronal, astrocytic, and microglial markers; nuclear protein (NeuN), Glial fibrillary acidic protein (GFAP), and Ionized calcium-binding adaptor molecule 1 (Iba1), respectively, and for an apoptosis marker; caspase-3, and the inflammatory marker; nuclear factor kappa B (NF-kB) signaling, heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2); physiological antioxidant system. The results showed that Losartan caused recovery of spinal cord changes, by inhibiting the microglial and astrocytic activation, suppressing neuronal apoptosis and NF-kB expression with activation of Nrf2/HO-1 (P<0.0005). It is suggested, herein, that Losartan can suppress diabetes-induced glial activation, inflammation, neuronal apoptosis, and oxidative stress in the spinal cord; the mechanisms that may underlie the role of AT1 antagonism in suppressing diabetic neuropathic pain.

Astragalus polysaccharides promote neural stem cells-derived oligodendrogenesis through attenuating CD8+T cell infiltration in experimental autoimmune encephalomyelitis

Endogenous neural stem cells (NSCs) have the potential to generate remyelinating oligodendrocytes, which play an important role in multiple sclerosis (MS). However, the differentiation of NSCs into oligodendrocytes is insufficient, which is considered a major cause of remyelination failure. Our previous work reported that Astragalus polysaccharides (APS) had a neuroprotective effect on experimental autoimmune encephalomyelitis (EAE) mice. However, it remains unclear whether APS regulate NSCs differentiation in EAE mice. In this study, our data illustrated that APS administration could promote NSCs in the subventricular zone (SVZ) to differentiate into oligodendrocytes. Furthermore, we found that APS significantly improved neuroinflammation and inhibited CD8+T cell infiltration into SVZ of EAE mice. We also found that MOG35-55-specific CD8+T cells suppressed NSCs differentiation into oligodendrocytes by secreting IFN-γ, and APS facilitated the differentiation of NSCs into oligodendrocytes which was related to decreased IFN-γ secretion. In addition, APS treatment did not show a better effect on the NSCs-derived oligodendrogenesis after CD8+T cell depletion. This present study demonstrated that APS alleviated neuroinflammation and CD8+T cell infiltration into SVZ to induce oligodendroglial differentiation, and thus exerted neuroprotective effect. Our findings revealed that reducing the infiltration of CD8+T cells might contribute to enhancing NSCs-derived neurogenesis. And APS might be a promising drug candidate to treat MS.

Association of medicinal plant consumption with all-cause mortality and cognitive impairment in older adult: A large prospective cohort study

BACKGROUND

Panax ginseng and other medicinal plants have long been believed to have beneficial effects on health, and there is substantial evidence supporting their mechanisms of action. However, the extent of the health benefits derived from consuming these medicinal plants lacks substantial evidence from large-scale longitudinal population studies. The purpose of this study was to analyze the effect of consuming these medicinal plants on all-cause mortality and cognitive impairment.

METHODS

A population-based cohort study was conducted using the Chinese Longitudinal Healthy Longevity Survey (CLHLS), which was established in 1998 and has been followed up till now. The main exposure was the frequency of eating medicinal plants, including Panax ginseng, Astragalus membranaceus, Lycium barbarum, Angelica sinensis, etc. According to the consumption patterns of medicinal plants, the participants were divided into three groups: frequent use, occasional use, and rarely or never use group. The participants were individually tracked to determine their mortality and cognitive impairment status during the period from 2008 to 2018. Cox proportional hazards regression and competing risk model were used to calculate the hazard ratio (HR) for the association between the use of medicinal plants and the all-cause mortality and cognitive impairment.

RESULTS

Among 13,918 participants, the average age was 87.2 ± 11.3 years old, and 70.1% (9,754/13,918) of the participants died during follow-up. The proportion of those frequently using, occasionally using, and rarely using medicinal plants was 8.4%, 20.7%, and 70.8%, respectively. Compared with the rarely or never use group, the occasional and frequent use groups demonstrated significantly lower risks for all-cause mortality, with HR of 0.75 (95% CI: 0.71 - 0.79) and 0.53 (95% CI: 0.49 - 0.58), respectively. The protective effect of medicinal plants against all-cause mortality decreased with increasing age in the subgroup analysis. Additionally, frequent use of medicinal plants reduced the risk of cognitive impairment in the competing risk model (HR = 0.73, 95% CI: 0.60 - 0.87). However, there was no protective effect on cognitive function for those who occasional use medicinal plants.

CONCLUSION

In elderly individuals, occasional and frequent use of medicinal plants was associated with reductions in risk of all-cause mortality, and frequent use of medicinal plants could reduce the risk of cognitive impairment.

Astragalus Polysaccharide Promotes Doxorubicin-Induced Apoptosis by Reducing O-GlcNAcylation in Hepatocellular Carcinoma

The toxicity and side effects of chemotherapeutic drugs remain a crucial obstacle to the clinical treatment of hepatocellular carcinoma (HCC). Identifying combination therapy from Chinese herbs to enhance the sensitivity of tumors to chemotherapeutic drugs is of particular interest. Astragalus polysaccharide (APS), one of the natural active components in Astragalus membranaceus, has been reported to exhibit anti-tumor properties in diverse cancer cell lines. The aim of this study was to determine the effect of APS on Doxorubicin (Dox)-induced apoptosis in HCC and the underlying mechanism. The results showed that APS dose-dependently promoted Dox-induced apoptosis and enhanced endoplasmic reticulum (ER) stress. Additionally, APS decreased the mRNA level and protein stability of O-GlcNAc transferase (OGT), and increased the O-GlcNAcase (OGA) expression. Furthermore, OGT lentiviral transfection or PugNAc (OGA inhibitor) treatment reversed the ER stress and apoptosis induced by the combination of Dox and APS. A xenograft tumor mouse model confirmed that the combination of APS and Dox showed an advantage in inhibiting tumor growth in vivo. These findings suggested that APS promoted Dox-induced apoptosis in HCC cells through reducing the O-GlcNAcylation, which led to the exacerbation of ER stress and activation of apoptotic pathways.

The functions of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in diabetes progression

The increase in blood glucose causes a myriad of pathways and molecular components to malfunction, leading to diabetes. Diabetes affects each organ differently by activating distinct pathways. It has an impact on the liver, pancreas, kidney (nephropathy), eyes (retinopathy), and nervous system (neuropathy). Understanding the effects of diabetes on each organ is the first step in developing a sustained treatment for the disease. Among the many cellular molecules impacted by diabetes is Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), a complex Ca²⁺/calmodulin-activated serine/threonine-protein kinase. When intracellular [Ca²⁺] rises, it binds to calmodulin (CaM) to produce Ca²⁺/CaM, which activates CaMKIIs. This factor is involved in the pancreas, liver, heart, muscles, and various organs. Thus, Understanding CaMKII action in each organ is critical for gaining a complete picture of diabetic complications. Therefore, this review covers CaMKII's functions in many organs and how it affects and has been affected by diabetes.

Neuroprotective Effect of Barbaloin on Streptozotocin-Induced Cognitive Dysfunction in Rats via Inhibiting Cholinergic and Neuroinflammatory Cytokines Pathway-TNF-α/IL-1β/IL-6/NF-κB

Streptozotocin (STZ) impairs memory in rats through altering the central nervous systems (CNS) as a result of impaired cholinergic dysfunction, oxidative stress, persistent hyperglycemia, and alterations in the glucagon-like peptide (GLP). In this model cholinergic agonist, antioxidant and antihyperglycemic treatment has been shown to have positive effects. Barbaloin has a variety of pharmacological effects. However, there is no evidence on how barbaloin improves memory dysfunction caused by STZ. Thus, we examined its effectiveness against cognitive damage caused by STZ at a dose of 60 mg/kg i.p. in Wistar rats. Blood glucose levels (BGL) and body weight (BW) were assessed. To assess learning and memory skills, the Y-maze test and Morris water maze (MWM) test were utilized. Superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), and glutathione (GSH) as oxidative stress markers were regulated to reverse the cognitive deterioration, and choline-acetyltransferase (ChAT) and acetyl-cholinesterase (AChE) as indicators of cholinergic dysfunction, nuclear factor kappa-B (NF-κB), IL-1β (interleukin-1β), IL-6, and tumor necrosis factor-α (TNF-α) contents were used. Barbaloin treatment thereby significantly decreased the BW and learning and memory capacities, resulting in substantial behavioral improvement in the Y-maze and MWM test. BGL, SOD, CAT, MDA, GSH, AChE, ChAT, NF-κB, IL-6, TNF-α, and IL-1β levels were also altered. In conclusion, the findings revealed that barbaloin had a protective impact against cognitive dysfunction caused by STZ.

Natural products regulate mitochondrial function in cognitive dysfunction-A scoping review

Medicines from natural products can not only treat neurodegenerative diseases but also improve the cognitive dysfunction caused by treatments with western medicines. This study reviews the literature related to the regulation of mitochondrial participation in cognitive function by natural products. In this study, we focused on English articles in PubMed, Web of Science, and Google Scholar, from 15 October 2017, to 15 October 2022. Fourteen studies that followed the inclusion criteria were integrated, analyzed, and summarized. Several studies have shown that natural products can improve or reduce cognitive dysfunction by ameliorating mitochondrial dysfunction. These results suggest that natural products may serve as new therapeutic targets for neurodegenerative diseases.

Astragalus Polysaccharide Relieves Inflammatory Responses in Guinea Pigs with Allergic Rhinitis via Ameliorating NF-kB-Mediated Treg/Th17 Imbalance

BACKGROUND

Allergic rhinitis (AR) is regarded as a prevalent and non-infectious inflammation in nasal mucosa, and astragalus polysaccharide (APS) could mitigate inflammation.

OBJECTIVES

Herein, this study probed the specific mechanism of APS in inflammatory responses in AR.

METHODS

Firstly, AR guinea pig models were established through the stimulation and sensitization of ovalbumin (OVA) and received APS treatment. Changes in nasal symptoms were assessed through counting the sneezing and rubbing times of guinea pigs. The change patterns of OVA-specific immunoglobulin-E (OVA-sIgE), OVA-specific immunoglobulin-G1 (OVA-sIgG1), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in guinea pig serum were identified. Meanwhile, the levels of IL-17, transforming growth factor (TGF)-β, IL-10, and forkhead box protein P3 (Foxp3) in the guinea pig tissues or serum were examined, and CD25⁺Foxp3⁺Treg or CD4⁺IL17⁺Th17 cell proportion was detected. Afterwards, nuclear factor-kappa B (NF-kB) expression in guinea pig nasal mucosa tissues were examined. Rescue experiments were designed to probe the role of NF-kB overexpression in inflammatory responses and Treg/Th17 imbalance in AR guinea pigs.

RESULTS

APS treatment reduced sneezing and rubbing times of AR guinea pigs and suppressed OVA-sIgE, OVA-sIgG1, TNF-α, and IL-6 levels in guinea pig serum, and meanwhile, increased CD25⁺Foxp3⁺Treg cell proportion while reduced CD4⁺IL17⁺Th17 cell proportion in AR guinea pig serum or tissues, in a dose-dependent manner. NF-kB was highly-expressed in AR guinea pigs and down-regulated after APS treatment. NF-kB overexpression facilitated inflammatory responses and Treg/Th17 imbalance in AR.

CONCLUSION

APS reduced Treg/Th17 imbalance via suppressing NF-kB expression, thereby ameliorating inflammatory responses in AR.

Effects of Astragalus Polysaccharides on CD8+ Tissue-Resident Memory T Cells in Mice with Herpes Simplex

Objective

This study aimed to explore whether astragalus polysaccharides (APS) could treat herpes simplex by increasing tissue-resident memory CD8+ T cells (CD8+ TRM cells) and analyze its potential mechanism using the network pharmacologic approach.

Methods

C57BL/6J male mice aged 6–8 weeks were divided into a model group with HSV-1 infection treated by saline, a control group without HSV-1 infection but treated by saline, and an APS group with HSV-1 infection treated by APS. Clinical signs were observed, and the disease score was recorded every day. The skin lesions on day 9 after infection were taken for flow cytometric analysis to evaluate CD8+ TRM cells. Network pharmacologic analysis was performed to select the potential protein targets of astragalus associated with herpes simplex. Besides, Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed. The peripheral blood from the retroorbital venous plexus was collected to evaluate the levels of serum interferon-γ (IFN-γ) and interleukin 12 (IL-12). The comparisons of clinical signs, the disease score, CD8+ TRM cells, the serum IFN-γ, and IL-12 levels were performed among the three groups.

Results

Compared with the model group, the disease score in the APS group was significantly lower (p < 0.05). On the day 9 after HSV-1 infection, there was no significant difference in the body weight of mice among the three groups. However, compared with the control group or model group, the spleen weight in the APS group increased significantly (p < 0.05). The surface antigens of CD8+ TRM cells had no significant difference between the control group and the model group, while compared with the model group, the surface antigens of CD8 (p < 0.05), CD69 (p < 0.05), and CD103 (p < 0.05) in the APS group increased significantly. Moreover, the serum IL-12 (p < 0.05) and IFN-γ (p < 0.01) levels in the APS group increased significantly compared with the model group.

Conclusion

Our study suggested that APS could alleviate the symptoms of the mice infected with HSV-1, and CD8+ TRM cells in the skin lesions and the levels of IL-12 and IFN-γ in the serum of mice with HSV-1 infection increased after the APS treatment, of which the specific underlying mechanism requires further experiments to clarify. In addition, the antiviral effect of APS might be worthy of further development and utilization.

[Protective Effects of Akkermansia muciniphila and Amuc_1100 Protein on Rats on High-Fat Diet Combined with Streptozotocin Injection]

OBJECTIVE

To explore the protective effects of live or pasteurized Akkermansia muciniphila and Amuc_1100 protein on a rat model of diabetes mellitus induced by high-fat diet (HFD) combined with streptozotocin (STZ).

METHODS

A total of 96 Sprague-Dawley (SD) rats were randomly assigned to 8 groups, including 6 experimental groups and 2 control groups, with 12 rats in each group. HFD combined with STZ injection was given to the rats to create a simulated model of the progression of diabetes mellitus type 2. In addition, the rats were treated with different doses of live or pasteurized Akkermansia muciniphila or Amuc_1100 protein by way of gavage for 8 weeks simultaneously. Plasma samples were collected to determine the level of parameters related to lipid and glucose metabolism, and inflammation mediators. Colon tissue specimens were collected for HE staining. Stool samples of the rats were collected for 16S rRNA gene sequencing.

RESULTS

Compared with the HFD control group, rats in the group treated with Akkermansia muciniphila exhibited significantly lower body mass gain ( P<0.01) and lower plasma TNF-α level ( P<0.05). Administration of Akkermansia muciniphila or Amuc_1100 protein increased the number of goblet cells and mucin secretion. The β diversity analysis of the samples showed no overall difference in the intervention groups.

CONCLUSION

Oral administration of Akkermansia muciniphila can effectively ameliorate HFD-induced metabolic disorders, including body mass gain and systemic inflammation. Akkermansia muciniphila and Amuc_1100, to a certain degree, improved the gut barrier function. After eight weeks of intervention, there was no significant impact on the structure of the gut microbiota.

Astragalus polysacharin inhibits hepatocellular carcinoma-like phenotypes in a murine HCC model through repression of M2 polarization of tumour-associated macrophages

CONTEXT

Astragalus polysaccharin (APS), an extract of Astragalus propinquus Schischk, exerts antitumor effects in hepatocellular carcinoma (HCC).

OBJECTIVE

This study investigated the mechanism of action of APS in HCC.

MATERIALS AND METHODS

Tumour-associated macrophages (TAMs) were treated with APS (0, 8, 16 mg/mL) for 24 h. APS (16 mg/mL)-treated TAMs were co-cultured with MHCC97H/Huh7 cells for 24 h. Finally, BALB/c nude mice were divided into PBS, APS (50 mg/kg), APS (100 mg/kg), APS (200 mg/kg) groups: mice were inoculated with Huh7 cells to construct tumour xenograft model, followed by administration of APS (50, 100, 200 mg/kg) or PBS daily for 30 days. Cell proliferation, migration, invasion, tumour growth, macrophage markers and proportions were measured.

RESULTS

APS 16 mg/mL treatment enhanced the expression of M1 macrophage markers (iNOS, IL-1β and TNF-α) and M1 macrophage proportions, while reducing the expression of M2 macrophage markers (IL-10, Arg-1) and M2 macrophage proportions in TAMs. Moreover, the APS-mediated M1 phenotype of TAMs significantly repressed cell proliferation, migration and invasion of MHCC97H and Huh7 cells. Moreover, APS (50, 100, 200 mg/kg) enhanced M1 macrophage proportions and reduced M2 macrophage proportions in the tumour tissues, and thus inhibited tumour growth of HCC.

DISCUSSION AND CONCLUSIONS

APS inhibits HCC-like phenotypes in a murine HCC model through repression of M2 polarization of TAMs. This work provides a novel theoretical basis for the application of APS in the clinical treatment of HCC.

Ekakitie L, Kappo AP. Effect of Solanum macrocarpon Linn leaf aqueous extract on the brain of an alloxan-induced rat model of diabetes

Objective

This study was designed to evaluate the protective effect of aqueous extract of Solanum macrocarpon Linn leaf in the brain of an alloxan-induced rat model of diabetes.

Methods

The experimental model of diabetes was induced by a single intraperitoneal injection of freshly prepared alloxan. Rats were then divided into six groups: normal control, diabetes control, diabetes group treated with metformin, and three diabetes groups treated with different concentrations of S. macrocarpon. Rats were sacrificed on day 14 of the experiment and different brain biochemical parameters were assessed and compared between groups.

Results

Administration of different doses of S. macrocarpon leaf aqueous extract was associated with significantly reduced levels of fasting blood glucose, lipid peroxidation, neurotransmitters, cholinesterases, cyclooxygenase-2 and nitric oxide compared with diabetes control rats. In addition, antioxidant enzyme activities were significantly increased in diabetes rats administered 12.45, 24.9 and 49.8 mg/kg body weight of S. macrocarpon versus diabetes control rats.

Conclusion

Aqueous extract of S. macrocarpon Linn leaf may be useful in the management of diabetic neuropathy.

Network Pharmacology-Based Identification of the Mechanisms of Shen-Qi Compound Formula in Treating Diabetes Mellitus

Aim

The purpose of this research is to identify the mechanisms of Shen-Qi compound formula (SQC), a traditional Chinese medicine (TCM), for treating diabetes mellitus (DM) using system pharmacology.

Methods

The active components and therapeutic targets were identified, and these targets were analyzed using gene ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and protein-protein interaction (PPI) analysis. Finally, an integrated pathway was constructed to show the mechanisms of SQC.

Results

A total of 282 active components and 195 targets were identified through a database search. The component-target network was constructed, and the key components were screened out according to their degree. Through the GO, PPI, and KEGG analyses, the mechanism network of SQC treating DM was constructed.

Conclusions

This study shows that the mechanisms of SQC treating DM are related to various pathways and targets. This study provides a good foundation and basis for further in-depth verification and clinical application.

The neuroprotective effect and action mechanism of polyphenols in diabetes mellitus-related cognitive dysfunction

BACKGROUND

Diabetes mellitus (DM) is a complex and prevalent metabolic disorder worldwide. Strong evidence has emerged that DM is a risk factor for the accelerated rate of cognitive decline and the development of dementia. Though traditional pharmaceutical agents are efficient for the management of DM and DM-related cognitive decrement, long-term use of these drugs are along with undesired side effects. Therefore, tremendous studies have focused on the therapeutic benefits of natural compounds at present. Ample evidence exists to prove that polyphenols are capable to modulate diabetic neuropathy with minimal toxicity and adverse effects.

PURPOSE

To describe the benefits and mechanisms of polyphenols on DM-induced cognitive dysfunction. In this review, we introduce an updated overview of associations between DM and cognitive dysfunction. The risk factors as well as pathological and molecular mechanisms of DM-induced cognitive dysfunction are summarized. More importantly, many active polyphenols that possess preventive and therapeutic effects on DM-induced cognitive dysfunction and the potential signaling pathways involved in the action are highlighted.

CONCLUSIONS

The therapeutic effects of polyphenols on DM-related cognitive dysfunction pave a novel way for the management of diabetic encephalopathy.

Review of the Effect of Natural Compounds and Extracts on Neurodegeneration in Animal Models of Diabetes Mellitus

Diabetes mellitus is a chronic metabolic disease with a high prevalence in the Western population. It is characterized by pancreas failure to produce insulin, which involves high blood glucose levels. The two main forms of diabetes are type 1 and type 2 diabetes, which correspond with >85% of the cases. Diabetes shows several associated alterations including vascular dysfunction, neuropathies as well as central complications. Brain alterations in diabetes are widely studied; however, the mechanisms implicated have not been completely elucidated. Diabetic brain shows a wide profile of micro and macrostructural changes, such as neurovascular deterioration or neuroinflammation leading to neurodegeneration and progressive cognition dysfunction. Natural compounds (single isolated compounds and/or natural extracts) have been widely assessed in metabolic disorders and many of them have also shown antioxidant, antiinflamatory and neuroprotective properties at central level. This work reviews natural compounds with brain neuroprotective activities, taking into account several therapeutic targets: Inflammation and oxidative stress, vascular damage, neuronal loss or cognitive impairment. Altogether, a wide range of natural extracts and compounds contribute to limit neurodegeneration and cognitive dysfunction under diabetic state. Therefore, they could broaden therapeutic alternatives to reduce or slow down complications associated with diabetes at central level.