Neuroprotective effect of anthocyanin on experimental traumatic spinal cord injury

Mapping the landscape: A bibliometric perspective on autophagy in spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is a severe condition that often leads to persistent damage of nerve cells and motor dysfunction. Autophagy is an intracellular system that regulates the recycling and degradation of proteins and lipids, primarily through lysosomal-dependent organelle degradation. Numerous publications have highlighted the involvement of autophagy in the secondary injury of SCI. Therefore, gaining a comprehensive understanding of autophagy research is crucial for designing effective therapies for SCI.

METHODS

Dates were obtained from Web of Science, including articles and article reviews published from its inception to October 2023. VOSviewer, Citespace, and SCImago were used to visualized analysis. Bibliometric analysis was conducted using the Web of Science data, focusing on various categories such as publications, authors, journals, countries, organizations, and keywords. This analysis was aimed to summarize the knowledge map of autophagy and SCI.

RESULTS

From 2009 to 2023, the number of annual publications in this field exhibited wave-like growth, with the highest number of publications recorded in 2020 (44 publications). Our analysis identified Mei Xifan as the most prolific author, while Kanno H emerged as the most influential author based on co-citations. Neuroscience Letters was found to have published the largest number of papers in this field. China was the most productive country, contributing 232 publications, and Wenzhou Medical University was the most active organization, publishing 39 papers.

CONCLUSION

We demonstrated a comprehensive overview of the relationship between autophagy and SCI utilizing bibliometric tools. This article could help to enhance the understanding of the field about autophagy and SCI, foster collaboration among researchers and organizations, and identify potential therapeutic targets for treatment.

Nanotechnology as a Tool to Mitigate the Effects of Intestinal Microbiota on Metabolization of Anthocyanins

Anthocyanins are an important group of phenolic compounds responsible for pigmentation in several plants. For humans, a regular intake is associated with a reduced risk of several diseases. However, molecular instability reduces the absorption and bioavailability of these compounds. Anthocyanins are degraded by external factors such as the presence of light, oxygen, temperature, and changes in pH ranges. In addition, the digestion process contributes to chemical degradation, mainly through the action of intestinal microbiota. The intestinal microbiota has a fundamental role in the biotransformation and metabolization of several dietary compounds, thus modifying the chemical structure, including anthocyanins. This biotransformation leads to low absorption of intact anthocyanins, and consequently, low bioavailability of these antioxidant compounds. Several studies have been conducted to seek alternatives to improve stability and protect against intestinal microbiota degradation. This comprehensive review aims to discuss the existing knowledge about the structure of anthocyanins while discussing human absorption, distribution, metabolism, and bioavailability after the oral consumption of anthocyanins. This review will highlight the use of nanotechnology systems to overcome anthocyanin biotransformation by the intestinal microbiota, pointing out the safety and effectiveness of nanostructures to maintain molecular stability.

Effect of curcumin on the inflammatory reaction and functional recovery after spinal cord injury in a hyperglycemic rat model

BACKGROUND CONTEXT

Curcumin has anti-inflammatory and antioxidant activities.

OBJECTIVE

This study aimed to investigate the effects of curcumin on the histological changes and functional recovery following spinal cord injury (SCI).

STUDY DESIGN

One hundred twenty-eight Sprague-Dawley rats were distributed into a sham, SCI only, SCI-hyperglycemia, and SCI-hyperglycemia-curcumin (200 mg/kg/day, i.p.) groups.

METHODS

SCI was induced using a clip at T9-10 and hyperglycemia was induced by streptozotocin (60-70 mg/kg, i.v.). Plasma malondialdehyde levels and superoxide dismutase activity was measured to determine oxidative stress. The activity of macrophages in the spinal cord after SCI was stained by the anti-CD68 antibody (ED-1). The tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 levels were measured by enzyme-linked immunosorbent assay and Western blot was used to verify the levels of mitogen-activated protein kinases and STAT3. The glial fibrillary acidic protein expression was evaluated by immunofluorescence analysis. Functional recovery was assessed according to the Basso, Beattie, and Bresnahan scale and histologic outcome was evaluated by the lesion volume and spared tissue area.

RESULTS

Superoxide dismutase activity increased, the malondialdehyde level decreased, and ED-1 macrophage marker level decreased in the SCI-hyperglycemia-curcumin group than in the SCI-hyperglycemia group at 2 weeks after SCI (p<.01). The SCI-hyperglycemia-curcumin group showed a statistically significant reduction in IL-6, IL-8, and TNF-α levels compared with the SCI-hyperglycemia group after SCI. The phosphorylated-extracellular signal-regulated kinase, phosphorylated-JNK, and phospho-p38 levels were significantly lower in the SCI-hypoglycemia-curcumin group than in the SCI-hypoglycemia group. The SCI-hyperglycemia-curcumin group showed a decrease in glial fibrillary acidic protein expression after SCI compared with the SCI-hyperglycemia group. The SCI-hyperglycemia-curcumin group showed a lower lesion volume, higher spared tissue, and better functional recovery than the SCI-hyperglycemia group.

CONCLUSIONS

Curcumin may have a potential neuroprotective effect in SCI with hyperglycemia.

CLINICAL SIGNIFICANCE

Curcumin decreased the inflammatory response and decreased astrogliosis and improved the functional recovery and histologic outcomes in SCI with hyperglycemia.

A Close Look at Echium amoenum Processing, Neuroactive Components, and Effects on Neuropsychiatric Disorders

Pharmacological researches in the area of herbal medicine have considerably increased over the last two centuries. Echium amoenum (known as Gol-e-Gavzaban in Persian) is a medicinal plant that has been widely used in Iranian folk medicine. In this review, databases including PubMed, Scopus, and Google Scholar were searched up. Data collecting was completed by January 2019 and available scientific reports regarding the processing methods, main chemical constituents, and effects of E. amoenum on different neuropsychiatric disorders are summarized. Thirteen five studies met the inclusion criteria. According to results, the important phytochemicals of the plant was phenolic compounds, fatty acids, rosmarinic acid, anthocyanidins, and flavonoids. Also, experimental and clinical studies demonstrated the effectiveness of E. amoenum in the treatment of several neuropsychiatric disorders such as anxiety, depression, ischemic stroke, seizure, Alzheimer's disease, and pain. Many of these effects are, at least in part, due to its rosmarinic acid or polyphenolic compounds such as flavonoids and natural pigments such as anthocyanins. Also, fatty acids such as gamma-linolenic acid play critical role in neuroactive properties of this herb. Among these effects, only the antidepressant and anxiolytic properties of the plant extract have been examined both experimentally and clinically. There was some controversy over its toxicity effects. It seems that E. amoenum protects neurons via attenuation of oxidative stress and inflammation as well as blocking of apoptosis in the nervous system. However, more studies are necessary for assessing exact mechanisms of action in neuropsychiatric disorders, finding of bioactive ingredients, and processing methods of this plant.

The Impact of O-Glycosylation on Cyanidin Interaction with RBCs and HMEC-1 Cells-Structure⁻Activity Relationships

With the aim of contributing to the knowledge about their potential therapeutic activity, we determined the biological activities of cyanidin and its selected O-glycosides in relation to erythrocytes (RBCs) and human dermal vascular endothelial cells (HMEC-1). Furthermore, on the basis of changes in the physical/functional properties of the cells, the structure–activity relationships of the compounds were determined. Concerning erythrocytes, we analyzed the antioxidant activity of the compounds and their impact on the RBCs’ shape and transmembrane potential. The compounds’ cytotoxic activity, ability to modulate apoptosis, cell cycle, and intracellular ROS generation, as well as inhibitory activity against AAPH-inducted oxidative stress, were determined in relation to HMEC-1 cells. We demonstrated that biological activity of cyanidin and its O-glycosides strongly depends on the number and type of sugar substituents, and varies depending on the extracellular environment and type of cells. The compounds are practically non-cytotoxic, and do not induce apoptosis or disturb the progression of the cell cycle. Additionally, the compounds alter the shape of RBCs, but they do not affect their transmembrane potential. They effectively protect erythrocytes against free radicals and affect intracellular reactive oxygen spices (ROS) generation under physiological and AAPH-induced oxidative stress conditions. Our results suggest a potential beneficial effect of cyanidin on the cardiovascular system.

Review of the UBC Porcine Model of Traumatic Spinal Cord Injury

Traumatic spinal cord injury (SCI) research has recently focused on the use of rat and mouse models for in vivo SCI experiments. Such small rodent SCI models are invaluable for the field, and much has been discovered about the biologic and physiologic aspects of SCI from these models. It has been difficult, however, to reproduce the efficacy of treatments found to produce neurologic benefits in rodent SCI models when these treatments are tested in human clinical trials. A large animal model may have advantages for translational research where anatomical, physiological, or genetic similarities to humans may be more relevant for pre-clinically evaluating novel therapies. Here, we review the work carried out at the University of British Columbia (UBC) on a large animal model of SCI that utilizes Yucatan miniature pigs. The UBC porcine model of SCI may be a useful intermediary in the pre-clinical testing of novel pharmacological treatments, cell-based therapies, and the “bedside back to bench” translation of human clinical observations, which require preclinical testing in an applicable animal model.

Therapeutic potential of flavonoids in spinal cord injury

Spinal cord injury (SCI) is a catastrophic event that can profoundly affect a patient's life, with far-reaching social and economic effects. A consequential sequence of SCI is the significant neurological or psychological deficit, which obviously contributes to the overall burden of this condition. To date, there is no effective treatment for SCI. Therefore, developing novel therapeutic strategies for SCI is highly prioritized. Flavonoids, one of the most numerous and ubiquitous groups of plant metabolites, are the active ingredients of traditional Chinese medicine such as Scutellaria baicalensis Georgi (Huang Qin) or Ginkgo biloba (Ying Xin). Accumulated research data show that flavonoids possess a range of key pharmacological properties such as anti-inflammatory, anti-oxidant, anti-tumor, anti-viral, anti-cardiovascular disease, immunomodulatory, and neuroprotective effects. Based on this, the flavonoids show therapeutic potential for SCI diseases. In this paper, we will review the pharmacological properties of different types of flavonoids for the treatment of SCI diseases, and potential underlying biochemical mechanisms of action will also be described.

Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits

Anthocyanins are colored water-soluble pigments belonging to the phenolic group. The pigments are in glycosylated forms. Anthocyanins responsible for the colors, red, purple, and blue, are in fruits and vegetables. Berries, currants, grapes, and some tropical fruits have high anthocyanins content. Red to purplish blue-colored leafy vegetables, grains, roots, and tubers are the edible vegetables that contain a high level of anthocyanins. Among the anthocyanin pigments, cyanidin-3-glucoside is the major anthocyanin found in most of the plants. The colored anthocyanin pigments have been traditionally used as a natural food colorant. The color and stability of these pigments are influenced by pH, light, temperature, and structure. In acidic condition, anthocyanins appear as red but turn blue when the pH increases. Chromatography has been largely applied in extraction, separation, and quantification of anthocyanins. Besides the use of anthocyanidins and anthocyanins as natural dyes, these colored pigments are potential pharmaceutical ingredients that give various beneficial health effects. Scientific studies, such as cell culture studies, animal models, and human clinical trials, show that anthocyanidins and anthocyanins possess antioxidative and antimicrobial activities, improve visual and neurological health, and protect against various non-communicable diseases. These studies confer the health effects of anthocyanidins and anthocyanins, which are due to their potent antioxidant properties. Different mechanisms and pathways are involved in the protective effects, including free-radical scavenging pathway, cyclooxygenase pathway, mitogen-activated protein kinase pathway, and inflammatory cytokines signaling. Therefore, this review focuses on the role of anthocyanidins and anthocyanins as natural food colorants and their nutraceutical properties for health. Abbreviations: CVD: Cardiovascular disease VEGF: Vascular endothelial growth factor.

Health benefits of anthocyanins and molecular mechanisms: Update from recent decade

Anthocyanins are one of the most widespread families of natural pigments in the plant kingdom. Their health beneficial effects have been documented in many in vivo and in vitro studies. This review summarizes the most recent literature regarding the health benefits of anthocyanins and their molecular mechanisms. It appears that several signaling pathways, including mitogen-activated protein kinase, nuclear factor κB, AMP-activated protein kinase, and Wnt/β-catenin, as well as some crucial cellular processes, such as cell cycle, apoptosis, autophagy, and biochemical metabolism, are involved in these beneficial effects and may provide potential therapeutic targets and strategies for the improvement of a wide range of diseases in future. In addition, specific anthocyanin metabolites contributing to the observed in vivo biological activities, structure-activity relationships as well as additive and synergistic efficacy of anthocyanins are also discussed.

SYSTEMATIC REVIEW OF RECOVERY OF SPINAL CORD INJURY WITH ANTIOXIDANT THERAPY

ABSTRACT The objective of the paper is to analyze the frequency and efficacy of experimental studies with antioxidant therapy. A search was conducted in the pubmed.gov database using the keywords "antioxidants" AND "spinal cord injury", from January 2000 to December 2015, resulting in 686 articles. Studies of non-traumatic injuries, non-antioxidant therapies, absence of neurological and functional evaluation, and non-experimental studies were excluded, leaving a total of 43 articles. The most used therapies were melatonin (16.2%), quercetin (9.3%), epigallocatechin and edaravone (6.9%). The most frequent route of administration was intraperitoneal (72.09%). The dose and mode of administration varied greatly, with a single dose being the most commonly used (39.53%). The time elapsed from trauma to treatment was 0-15 minutes (41.8%), 15-60 minutes (30%) and over 60 minutes (10.6%). Histological analysis was performed in 32 studies (74.41%). The BBB scale was the main functional measure applied (55.8%), followed by the inclined plane test (16.2%) and the Tarlov scale (13.9%). Positive outcomes were observed in 37 studies (86.04%). The heterogeneity of antioxidant therapy, with different types, doses, and measurements observed, limits the comparison of efficacy. Standardized protocols are required to make clinical translation possible.

Red Raspberries and Their Bioactive Polyphenols: Cardiometabolic and Neuronal Health Links

Diet is an essential factor that affects the risk of modern-day metabolic diseases, including cardiovascular disease, diabetes mellitus, obesity, and Alzheimer disease. The potential ability of certain foods and their bioactive compounds to reverse or prevent the progression of the pathogenic processes that underlie these diseases has attracted research attention. Red raspberries (Rubus idaeus L.) are unique berries with a rich history and nutrient and bioactive composition. They possess several essential micronutrients, dietary fibers, and polyphenolic components, especially ellagitannins and anthocyanins, the latter of which give them their distinctive red coloring. In vitro and in vivo studies have revealed various mechanisms through which anthocyanins and ellagitannins (via ellagic acid or their urolithin metabolites) and red raspberry extracts (or the entire fruit) could reduce the risk of or reverse metabolically associated pathophysiologies. To our knowledge, few studies in humans are available for evaluation. We review and summarize the available literature that assesses the health-promoting potential of red raspberries and select components in modulating metabolic disease risk, especially cardiovascular disease, diabetes mellitus, obesity, and Alzheimer disease-all of which share critical metabolic, oxidative, and inflammatory links. The body of research is growing and supports a potential role for red raspberries in reducing the risk of metabolically based chronic diseases.

Optimization of extraction parameters by using response surface methodology, purification, and identification of anthocyanin pigments in Melastoma malabathricum fruit

Anthocyanins not just have various benefits in food industry but also have been used as natural colourants in cosmetic, coating products and as potential natural photosensitizers in solar cell. Thus, the main purpose of this study was to obtain information on the maximum yield of anthocyanin that can be recovered from Melastoma malabathricum fruit. Factors such as extraction temperature, extraction time, and solid to liquid ratio were identified to be significantly affecting anthocyanin extraction efficiency. By using three-level three-factor Box-Behnken design, the optimized conditions for anthocyanin extraction by acidified methanol (R² = 0.972) were temperature of 60°C, time of 86.82 min, and 0.5 : 35 (g/mL) solid to liquid ratio while the optimum extraction conditions by acidified ethanol (R² = 0.954) were temperature of 60°C, time of 120 min, and 0.5 : 23.06 (g/mL) solid to liquid ratio. The crude anthocyanin extract was further purified by using Amberlite XAD-7 and Sephadex LH-20 column chromatography. Identification of anthocyanins revealed the presence of cyanidin dihexoside, cyanidin hexoside, and delphinidin hexoside as the main anthocyanins in M. malabathricum fruit.

Comparative analysis between thoracic spinal cord and sacral neuromodulation in a rat spinal cord injury model: a preliminary report of a rat spinal cord stimulation model

Objective

The purpose of this study is to compare a neuroprotective effect of thoracic cord neuromodulation to that of sacral nerve neuromodulation in rat thoracic spinal cord injury (SCI) model.

Methods

Twenty female Sprague Dawley rats were randomly divided into 4 groups: the normal control group (n=5), SCI with sham stimulation group (SCI, n=5), SCI with electrical stimulation at thoracic spinal cord (SCI + TES, n=5), and SCI with electrical stimulation at sacral nerve (SCI + SES, n=5). Spinal cord was injured by an impactor which dropped from 25mm height. Electrical stimulation was performed by the following protocol: pulse duration, 0.1ms; frequency, 20 Hz; stimulation time, 30 minutes; and stimulation duration at thoracic epidural space and S2 or 3 neural foramina for 4 weeks. Locomotor function, urodynamic study, muscle weights, and fiber cross sectional area (CSA) were investigated.

Results

All rats of the SCI + TES group expired within 3 days after the injury. The locomotor function of all survived rats improved over time but there was no significant difference between the SCI and the SCI + SES group. All rats experienced urinary retention after the injury and recovered self-voiding after 3-9 days. Voiding contraction interval was 25.5±7.5 minutes in the SCI group, 16.5±5.3 minutes in the SCI+SES group, and 12.5±4.2 minutes in the control group. The recovery of voiding contraction interval was significant in the SCI + SES group comparing to the SCI group (p<0.05). Muscle weight and CSA were slightly greater in the SCI + SES than in the SCI group, but the difference was not significant.

Conclusion

We failed to establish a rat spinal cord stimulation model. However, sacral neuromodulation have a therapeutic potential to improve neurogenic bladder and muscle atrophy.

Neuroprotective effects of sacral epidural neuromodulation following spinal cord injury : an experimental study in rats

Objective

The purpose of this study is to evaluate neuroprotective effect of sacral neuromodulation in rat spinal cord injury (SCI) model in the histological and functional aspects.

Methods

Twenty-one female Sprague Dawley rats were randomly divided into 3 groups : the normal control group (CTL, n=7), the SCI with sham stimulation group (SCI, n=7), and the SCI with electrical stimulation (SCI+ES, n=7). Spinal cord was injured by dropping an impactor from 25 mm height. Sacral nerve electrical stimulation was performed by the following protocol : pulse duration, 0.1 ms; frequency, 20 Hz; stimulation time, 30 minutes; and stimulation duration, 4 weeks. Both locomotor function and histological examination were evaluated as scheduled.

Results

The number of anterior horn cell was 12.3±5.7 cells/high power field (HPF) in the CTL group, 7.8±4.9 cells/HPF in the SCI group, and 6.9±5.5 cells/HPF in the SCI+ES group, respectively. Both the SCI and the SCI+ES groups showed severe loss of anterior horn cells and myelin fibers compared with the CTL group. Cavitation and demyelinization of the nerve fibers has no significant difference between the SCI group and the SCI+ES group. Cavitation of dorsal column was more evident in only two rats of SCI group than the SCI+ES group. The locomotor function of all rats improved over time but there was no significant difference at any point in time between the SCI and the SCI+ES group.

Conclusion

In a rat thoracic spinal cord contusion model, we observed that sacral neuromodulation did not prevent SCI-induced myelin loss and apoptosis.

Anthocyanins extracted from black soybean seed coat protect primary cortical neurons against in vitro ischemia

The present study investigated the neuroprotective effects of anthocyanins extracted from black soybean (cv. Cheongja 3, Glycine max (L.) MERR.) seed coat against oxygen-glucose deprivation (OGD) and glutamate-induced cell death in rat primary cortical neurons. Lactate dehydrogenase (LDH) release and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assays were employed to assess cell membrane damage and viability of primary neurons, respectively. OGD-induced cell death in 7 d in vitro primary cortical neurons was found to be OGD duration-dependent, and approximately 3.5 h of OGD resulted in ≈60% cell death. Treatment with black soybean anthocyanins dose-dependently prevented membrane damage and increased the viability of primary neurons that were exposed to OGD. Glutamate-induced neuronal cell death was dependent on the glutamate concentration at relatively low concentrations and the number of days the cells remained in culture. Interestingly, black soybean anthocyanins did not protect against glutamate-induced neuronal cell death. They did, however, inhibit the excessive generation of reactive oxygen species (ROS) and preserve mitochondrial membrane potential (MMP) in primary neurons exposed to OGD. In agreement with the neuroprotective effect of crude black soybean anthocyanins, purified cyanidin-3-glucoside (C3G), the major component of anthocyanins, also offered dose-dependent neuroprotection against OGD-induced neuronal cell death. Moreover, black soybean C3G markedly prevented excessive generation of ROS and preserved MMP in primary neurons that were exposed to OGD. Collectively, these results suggest that the neuroprotection of primary rat cortical neurons by anthocyanins that were extracted from black soybean seed coat might be mediated through oxidative stress inhibition and MMP preservation but not through glutamate-induced excitotoxicity attenuation.

The Neuroprotective Potential of Cyanidin-3-glucoside Fraction Extracted from Mulberry Following Oxygen-glucose Deprivation

In this study, cyanidin-3-glucoside (C3G) fraction extracted from the mulberry fruit (Morus alba L.) was investigated for its neuroprotective effects against oxygen-glucose deprivation (OGD) and glutamate-induced cell death in rat primary cortical neurons. Cell membrane damage and mitochondrial function were assessed by LDH release and MTT reduction assays, respectively. A time-course study of OGD-induced cell death of primary cortical neurons at 7 days in vitro (DIV) indicated that neuronal death was OGD duration-dependent. It was also demonstrated that OGD for 3.5 h resulted in approximately 50% cell death, as determined by the LDH release assay. Treatments with mulberry C3G fraction prevented membrane damage and preserved the mitochondrial function of the primary cortical neurons exposed to OGD for 3.5 h in a concentration-dependent manner. Glutamate-induced cell death was more pronounced in DIV-9 and DIV-11 cells than that in DIV-7 neurons, and an application of 50µM glutamate was shown to induce approximately 40% cell death in DIV-9 neurons. Interestingly, treatment with mulberry C3G fraction did not provide a protective effect against glutamate-induced cell death in primary cortical neurons. On the other hand, treatment with mulberry C3G fraction maintained the mitochondrial membrane potential (MMP) in primary cortical neurons exposed to OGD as assessed by the intensity of rhodamine-123 fluorescence. These results therefore suggest that the neuroprotective effects of mulberry C3G fraction are mediated by the maintenance of the MMP and mitochondrial function but not by attenuating glutamate-induced excitotoxicity in rat primary cortical neurons.