Effect of sulfated polysaccharides from Laminaria japonica on vascular endothelial cells in psychological stress rats

Polysaccharides from Laminaria japonica protect memory abilities and neurogenesis in mice after cranial irradiation through ameliorating neuroinflammation and collagen IV degradation

BACKGROUND

Radiation-induced brain injury (RIBI) is one of the most common long-term complications for patients with malignant brain tumors after radiotherapy. At present, there is no effective treatment for RIBI. Recent studies have also confirmed that polysaccharides from laminaria japonica (LJP) display potential neuroprotective function. However, its mechanisms of neuroprotection remain unclear.

AIM

In this study, we aimed to explore the effect and underlying mechanism of LJP on neurogenesis in radiation-induced brain injury mice.

METHODS

SPF two-month-old male mice were randomly divided into control group (Con), LJP treatment group (LJP), irradiation group (IR), and irradiation with LJP treatment group (IR + LJP). LJP (40 mg/kg/day) was intraperitoneally injected at one day before radiation for seven consecutive days (once daily). The mice were exposed to 10 Gy × 2 fractionated doses, once every other day, with a total dose of 20 Gy. Changes in cognitive function of mice following radiation were evaluated by the Morris water maze test. Furthermore, body weight and general status of mice were measured throughout the experiment. Immunohistochemical staining for neural proliferating cells (Ki67+ cells) and immature neurons (DCX + cells) was utilized to assay changes of neurogenesis in hippocampus. Microglial activation and collagen IV deposition within the neurogenic microenvironment were observed respectively by immunohistochemical staining for Iba-1 and Collagen IV in the hippocampus. Levels of pro-inflammatory cytokines (TNF-α and IL-1β) in the hippocampus were detected by ELISA kits post-radiation.

RESULTS

Morris water maze test showed that LJP therapy markedly reduced the escape latency and increased the times of crossing platform and percent time of the target quadrant in the radiated mice. In addition, the decrease of the neural proliferating cells (Ki67+ cells) and immature neurons (DCX + cells) in the hippocampus of mice following irradiation was significantly mitigated by the LJP treatment, suggesting that LJP could prevent from neurogenesis damage after irradiation. LJP injection significantly attenuated degradation of collagen IV, activation of microglia, and increase of pro-inflammatory cytokines (TNF-α and IL-1β) levels in the neurogenic microenvironment of the hippocampus after radiation.

CONCLUSION

These findings suggest that LJP early treatment may mitigate radiation-induced cognitive impairments and that its mechanism may relate to its protection of neurogenesis by alleviating neuroinflammation and collagen IV degradation within the neurogenic microenvironment.

Polysaccharides from Laminaria japonica: an insight into the current research on structural features and biological properties

Laminaria japonica, one of the most widespread seafood consumed in China and many other nations, has been traditionally utilized as an effective therapeutically active substance for treating weight loss, phlegm elimination, and detumescence for more than 2000 years. Numerous studies have found that the polysaccharides play an indispensable role in the nutritional and medicinal value of L. japonica. Water extraction and alcohol precipitation method is the most used method. Approximately 56 LJPs were successfully isolated and purified from L. japonica, whereas only few of them were well characterized. Modern pharmacological studies have shown that L. japonica polysaccharides (LJPs) have high-order structural features and multiple biological activities, including anti-tumor, anti-thrombotic, anti-atherosclerosis, hypolipidemic, hypoglycemic, antioxidant, anti-inflammatory, renoprotective, and immunomodulatory. In addition, the structural characteristics of LJPs are closely related to their biological activity. In this review, the extraction and purification methods, structural characteristics, biological activities, clinical settings, toxicities, and structure-activity relationships of LJPs are comprehensively summarized. The structural characteristics and biological activities as well as the underlying molecular mechanisms of LJPs were also outlined. Furthermore, the clinical settings and structure-activity functions of LJPs were highlighted. Some research perspectives and challenges in the study of LJPs were also proposed.

Pharmacologic Application Potentials of Sulfated Polysaccharide from Marine Algae

With the advent of exploration in finding new sources for treating different diseases, one possible natural source is from marine algae. Having an array of potential benefits, researchers are interested in the components which comprise one of these activities. This can lead to the isolation of active compounds with biological activities, such as antioxidation of free radicals, anti-inflammation, antiproliferation of cancer cells, and anticoagulant to name a few. One of the compounds that are isolated from marine algae are sulfated polysaccharides (SPs). SPs are complex heterogenous natural polymers with an abundance found in different species of marine algae. Marine algae are known to be one of the most important sources of SPs, and depending on the species, its chemical structure varies. This variety has important physical and chemical components and functions which has gained the attention of researchers as this contributes to the many facets of its pharmacologic activity. In this review, recent pharmacologic application potentials and updates on the use of SPs from marine algae are discussed.

Protective effects of a mixed plant extracts derived from Astragalus membranaceus and Laminaria japonica on PTU-induced hypothyroidism and liver damages

Protective effects of a mixed hot water extracts of Astragalus membranaceus (AWE) and Laminaria japonica (LWE), AWE: LWE 85:15 (g/g; AL mix), were investigated against propylthiouracil (PTU)-induced hypothyroidism in rats. Rats were challenged with PTU, resulting in, increased thyroid gland weight, decreased liver weight and antioxidant activities, reduced serum tri-iodothyronine and thyroxine levels with increased thyroid stimulating hormone levels, and elevated serum aspartate aminotransferase level. However, orally administered AL mix with 100, 200, and 400 mg kg-1  day-1 , significantly inhibited such abnormalities, dose-dependently. Moreover, PTU-induced abnormal histological architecture of the rat thyroid gland and liver were also significantly ameliorated by an AL mix. The results suggested that, therapeutic use of AL mix for treating hypothyroidism can be characterized by its diversified active ingredients particularly iodine and ferulic acid as confirmed by phytochemical analyses. PRACTICAL APPLICATIONS: The AL mix has synergistic effects in modulating thyroid hormone synthesis and preventing liver damages in PTU-induced hypothyroid rats. These effects of AL mix are mainly related to its richness specifically in iodine and ferulic acid. The growing interests of iodine and ferulic acid in AL mix are principally due to their beneficial effects in releasing sufficient thyroid hormones in hypothyroid conditions and promoting liver-protective functions through its antioxidant and anti-inflammatory potentials, respectively. Moreover, the results of AL mix are well-matched with the effects of standard drug levothyroxine in the present study. Therefore, appropriate dosage of AL mix will be promising as new medicinal food for preventing thyroid dysfunctions and its related liver damages.

Sargassum hystrix as a Source of Functional Food to Improve Blood Biochemistry Profiles of Rats under Stress

This study was conducted to determine the influence of Sargassum hystrix powder (SHP) as an alternative source of functional food for treating in vivo stress by measuring levels of glucose, triacylglycerol, total cholesterol, and cortisol, and liver histopathology. Wistar rats aged 3 months and weighing 150~200 g were divided into 7 groups: normal control, fasting control, negative control (stress without adaptogen), and 4 experimental conditions (stress+0.18 mg/kg diazepam, stress+450 mg/kg pellet, stress+mixture of pellet with SHP 450 mg/kg, and stress+450 mg/kg of SHP). Intake of liquids and and body weight were measured daily. Blood samples were collected on day 0 (baseline), day 5, and day 10 to analyze levels of glucose, triacylglycerol, cholesterol, and cortisol. On day 10, rats were euthanized and livers were collected to observe the severity of inflammation. The results indicated that rats receiving SHP 450 mg/kg and the mixture of pellet with SHP 450 mg/kg showed a similar ability as those receiving diazepam 0.18 mg/kg to cope with stress, indicated by an improvement in all blood biochemistry parameters. Supplementation with SHP 450 mg/kg can be used as an alternative source of functional food for overcoming oxidative stress, as indicated by its ability to improve levels of blood glucose, triacylglycerol, total cholesterol, and cortisol, and to improve liver histology by decreasing severity of liver inflammation.

Digestibility of sulfated polysaccharide from the brown seaweed Ascophyllum nodosum and its effect on the human gut microbiota in vitro

Sulfated polysaccharides from marine algae exhibit various bioactivities with potential benefits for human health and well-being. In this study, the in vitro digestibility and fermentability of polysaccharides from the brown seaweed Ascophyllum nodosum (AnPs) were examined, and the effects of AnPs on gut microbiota were determined using high-throughput sequencing technology. Salivary amylase, artificial gastric juice, and intestinal juice had no effect on AnPs, but the molecular weight of AnPs and reducing sugar decreased significantly after fermentation by gut microbiota. AnPs significantly modulated the composition of the gut microbiota; in particular, they increased the relative abundance of Bacteroidetes and Firmicutes, suggesting the potential for AnPs to decrease the risk of obesity. Furthermore, the total SCFA content after fermentation increased significantly. These results suggest that AnPs have potential uses as functional food components to improve human gut health.

Danshensu, a major water-soluble component of Salvia miltiorrhiza, enhances the radioresponse for Lewis Lung Carcinoma xenografts in mice

The molecule 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoic acid (danshensu), a herbal preparation used in traditional Chinese medicine, has been found to possess potential antitumor and anti-angiogenesis effects. The aim of the present study was to investigate the efficacy of the combination of radiation therapy (RT) with danshensu in the treatment of Lewis lung carcinoma (LLC) xenografts, whilst exploring and evaluating the mechanism involved. In total, 8-week old female C57BL/6J mice were randomly assigned into 3 groups to receive: RT, RT + cisplatin and RT + danshensu, respectively, when LLC reached 100–150 mm³. Each group was divided into 7 subgroups according to the different irradiation doses that were administered. Tumor growth curves were created and the sensitization enhancement ratios of the drugs were calculated. The experiment was then repeated, and the 4 groups of tumor-bearing mice were treated with natural saline, danshensu, RT + danshensu and RT, respectively. The mice were sacrificed on day 7, and tumor tissue and blood were collected to determine microvessel density, the expression of proangiogenic factors, and the levels of blood thromboxane B₂ and 6-keto-prostaglandin-F1α. Tumor hypoxia was also detected using in vivo fluorescence imaging. With respect to LLC xenografts, treatment with danshensu + RT significantly enhanced the effects of tumor growth inhibition (P<0.05). Furthermore, tumor vasculature was remodeled and microcirculation was improved, which significantly reduced tumor hypoxia (P<0.05). The present study demonstrated that danshensu significantly enhanced the radioresponse of LLC xenografts in mice. The mechanism involved may be associated with the alleviation of tumor cell hypoxia following treatment with danshensu + RT, caused by the improvement of tumor microcirculation and the remodeling of tumor vasculature.

In vitro fermentation of sulfated polysaccharides from E. prolifera and L. japonica by human fecal microbiota

In vitro fermentation of the sulfated polysaccharides from seaweeds Enteromorpha prolifera and Laminaria japonica and their prebiotic effects on human fecal microbiota were investigated in this study. The sulfated polysaccharides were fermented in vitro for 48h by human fecal cultures. When 0.8g MWCOL (polysaccharides MWCO<30kD) from L. japonica was fermented, the pH in fecal cultures decreased from 6.5 to 5.1 and the levels of short chain fatty acids, such as acetic, butyric and lactic acids all significantly increased. After 48h fermentation, 0.8g MWCOL showed good effect on modulating the gut microflora balance, because the beneficial strains (Lactobacillus and Bifidobacterium) were both significantly higher than those in control group (p<0.05). As far as we know, this is the first report that consumption of sulfated polysaccharides from E. prolifera and L. japonica is beneficial to the ecosystem of the intestinal tract by increasing the populations of probiotics and short chain fatty acids. Furthermore, our reports indicated that molecular weight of sulfated polysaccharide from marine algae is related to its prebiotic effects.

Polysaccharide Extracted from Laminaria japonica Delays Intrinsic Skin Aging in Mice

This study aimed to determine the effect of topically applied Laminaria polysaccharide (LP) on skin aging. We applied ointment containing LP (10, 25, and 50 μg/g) or vitamin E (10 μg/g) to the dorsal skin of aging mice for 12 months and young control mice for 4 weeks. Electron microscopy analysis of skin samples revealed that LP increased dermal thickness and skin collagen content. Tissue inhibitor of metalloprotease- (TIMP-) 1 expression was upregulated while that of matrix metalloproteinase- (MMP-) 1 was downregulated in skin tissue of LP-treated as compared to untreated aging mice. Additionally, phosphorylation of c-Jun N-terminal kinase (JNK) and p38 was higher in aging skin than in young skin, while LP treatment suppressed phospho-JNK expression. LP application also enhanced the expression of antioxidative enzymes in skin tissue, causing a decrease in malondialdehyde levels and increases in superoxide dismutase, catalase, and glutathione peroxidase levels relative to those in untreated aging mice. These results indicate that LP inhibits MMP-1 expression by preventing oxidative stress and JNK phosphorylation, thereby delaying skin collagen breakdown during aging.

Looking Beyond the Terrestrial: The Potential of Seaweed Derived Bioactives to Treat Non-Communicable Diseases

Seaweeds are a large and diverse group of marine organisms that are commonly found in the maritime regions of the world. They are an excellent source of biologically active secondary metabolites and have been shown to exhibit a wide range of therapeutic properties, including anti-cancer, anti-oxidant, anti-inflammatory and anti-diabetic activities. Several Asian cultures have a strong tradition of using different varieties of seaweed extensively in cooking as well as in herbal medicines preparations. As such, seaweeds have been used to treat a wide variety of health conditions such as cancer, digestive problems, and renal disorders. Today, increasing numbers of people are adopting a "westernised lifestyle" characterised by low levels of physical exercise and excessive calorific and saturated fat intake. This has led to an increase in numbers of chronic Non-communicable diseases (NCDs) such as cancer, cardiovascular disease, and diabetes mellitus, being reported. Recently, NCDs have replaced communicable infectious diseases as the number one cause of human mortality. Current medical treatments for NCDs rely mainly on drugs that have been obtained from the terrestrial regions of the world, with the oceans and seas remaining largely an untapped reservoir for exploration. This review focuses on the potential of using seaweed derived bioactives including polysaccharides, antioxidants and fatty acids, amongst others, to treat chronic NCDs such as cancer, cardiovascular disease and diabetes mellitus.

Maturation of mouse bone marrow dendritic cells (BMDCs) induced by Laminaria japonica polysaccharides (LJP)

The seaweed Laminaria japonica has been investigated in a laboratory research for its medical significance and LJP has been purified now. The objective of present study was to look at effect of LJP on structural, phenotypic and functional maturation of murine BMDCs. The structural maturation of BMDCs induced by LJP was evaluated by transmission electron microscopy (TEM); The phenotypic maturation of BMDCs was studied by flow cytometry(FCM) and functional maturation of BMDCs was analyzed by FITC-dextran, acid phosphatase (ACP) activity and enzyme linked immunosorbent assay (ELISA). We hereby proved that LJP markedly induced maturation of BMDCs with the data of decreased the number of lysosomes, upregulated expression of CD80, CD83, CD86, CD40 and MHC II key membrane molecules on BMDCs, downregulated phagocytosis, enriched production of IL-12 and TNF-α secreted by BMDCs. Therefore it should be concluded that LJP was with strong ability to induce maturation of BMDCs. Our data provided direct evidence to suggest that LJP could be considered as an immune stimulant in improving immune handicapped situation and as a useful adjuvant in vaccine designing.