Sulfated Mesona chinensis Benth polysaccharide enhance the immunomodulatory activities of cyclophosphamide-treated mice

Immunostimulatory effects of rhamnogalacturonan-I fraction purified from Glycyrrhiza glabra roots on cyclophosphamide-induced immunosuppressed mice

The present study aimed to investigate the immunostimulatory activities of polysaccharides purified from Glycyrrhiza glabra root. First, five polysaccharide fractions were separated from G. glabra through hot water extraction, ethanol precipitation, enzymatic hydrolysis, and size exclusion chromatography. Among them, G. glabra polysaccharide-enzyme (GRPE)-I showed the potent stimulation effect on cytokine secretion from peritoneal macrophage. Moreover, glycosidic linkage analysis indicated the GRPE-I mainly comprised 4-linked galacturonic acid, 2,4-linked rhamnose, 3,6-linked galactose, 4,6-linked galactose, and 5-linked arabinosef, which are characteristics of rhamnogalacturonan (RG)-I type polysaccharide. Immunostimulatory effect of GRPE-I in vivo was investigated in cyclophosphamide (CTX)-induced immunosuppressed mice model. As a results, the pre-administration of GRPE-I demonstrated significant benefits against reducing body weight and damaging lymphoid tissue. Additionally, GRPE-I affected regulation of various immunocytes population such as macrophage, natural killer cell, CD4+ T cell, CD8+ T cell. Serum and spleen tissue analysis results indicate improvement about immunoglobulin and cytokine levels by GRPE-I. These results are strongly correlated with the activation of the mitogen-activated protein kinase and nuclear factor-kappa B pathways. Furthermore, CTX-induced short chain fatty acid impairment was reversed by GRPE-I. In conclusion, GRPE-I, which is a RG-I type polysaccharide isolated from G. glabra, exhibits significant potential as a novel immunomodulator.

Health Benefits of Monk Fruit under Traditional Dietary Patterns: Perspective on Immunity and Gut Microbiota Modulatory Functions

Monk fruit is the mature fruit of Siraitia grosvenorii (Swingle) C. Jeffrey (SG), which contains mogrosides and various nutrients with diverse benefits as a traditional edible herb. The immunomodulatory effects of the ingredients of monk fruit in daily diets are poorly understood. Monk fruit juice concentrate is a commercial product of monk fruit and in this study, the immune-enhancing activity, immunosuppressive prevention, and gut microbiota modulatory effects of the long-term consumption of its diluent (called SG juice) in daily drinking were investigated in both healthy and cyclophosphamide (CTX)-treated mice. The results indicated that SG juice consumption was beneficial to weight management and improved immunity in mice by enhancing various immune factors. 16S rRNA analysis found that SG juice impacted the diversity and gut microbiota composition with the enrichment of immune-related flora, including Alloprevotella, Bifidobacterium_pseudolongum, Lactobacillus, and Bacteroides_sartorii. Additionally, the daily intake of SG juice exerted preventive effects on immunosuppressive mice with the recovery of reduced body weight and immunoglobulin levels, and restoration of gut microbiota imbalance. These data provide scientific insights into the immunomodulatory effects of monk fruit and foresee its application in functional foods.

Brassica rapa L. (Tibetan Turnip) polysaccharide improves the immune function and regulates intestinal microbiota in immunosuppressive mice

In this paper, active polysaccharides were extracted from Brassica rapa L. polysaccharide (BRP), and structural characterization was preliminarily investigated. Its immunomodulatory activity and molecular biological mechanisms in cyclophosphamide-induced immunosuppressed mice were also explored, as well as its effects on intestinal microbiota. Results indicate that BRP is an acidic heteropolysaccharide with the main components of Ara, GalA, and GlcA and has α- and β-glycosidic linkages with pyranose bonds. The results of the study showed that BRP could effectively improve the thymus and spleen indices and repair Cy-induced immune tissue damage in immunosuppressed mice. Meanwhile, BRP increased the immune cell activity and antioxidant levels in mice. In addition, BRP increased the secretion of cytokines (IL-1β, IL-6, IL-10, and TNF-α) and immunoglobulins (IgA, IgG) in mouse serum. It also regulates the relative expression of genes related to the TLR4/NF-κB signaling pathways as well as regulates the diversity and composition of mouse intestinal microbiota. In conclusion, BRP was able to regulated the immune function in immunosuppressed mice, providing a theoretical basis for the development of immunomodulators.

Fecal Microbiota Transplantation Activity of Floccularia luteovirens Polysaccharides and Their Protective Effect on Cyclophosphamide-Induced Immunosuppression and Intestinal Injury in Mice

Floccularia luteovirens polysaccharides (FLP1s) have potential biological activities. Our previous study showed that FLP1s positively regulated gut immunity and microbiota. However, it is still unclear whether FLP1s mediate gut microbiota in immunosuppressed mice. This research aims to explore the relationship between FLP1-mediated gut microbes and intestinal immunity in immunosuppressed mice through fecal microbiota transplantation (FMT). The results demonstrated that FLP1s exhibited prebiotic and anti-immunosuppressive effects on CTX-induced immunosuppressed mice. FFLP1 treatment (microbiota transplantation from the fecal sample) remarkably elevated the production of sIgA and secretion of the anti-inflammatory cytokines IL-4, TNF-α, and IFN-γ in the intestine of CTX-treated mice, inducing activation of the MAPK pathway. Moreover, FFLP1s mitigated oxidative stress by activating the Nrf2/Keap1 signaling pathway and strengthened the intestinal barrier function by upregulating the expression level of tight junction proteins (occludin, claudin-1, MUC-2, and ZO-1). Furthermore, FFPL1s restored gut dysbiosis in CTX-treated immunosuppressed mice by increasing the abundance of Alloprevotella, Lachnospiraceae, and Bacteroides. They also modified the composition of fecal metabolites, leading to enhanced regulation of lipolysis in adipocytes, the cGMP-PKG pathway, the Rap1 signaling pathway, and ovarian steroidogenesis, as indicated by KEGG pathway analysis. These findings indicate that FLP1s could modulate the response of the intestinal immune system through regulation of the gut microbiota, thus promoting immune activation in CTX-treated immunosuppressed mice. FLP1s can serve as a natural protective agent against CTX-induced immune injury.

Hypolipidemic Effects of Mesona chinensis Benth Polysaccharides with Different Structures and Molecular Weights

Four novel Mesona chinensis Benth polysaccharides were isolated using aqueous alcohol precipitation. Their molecular weights were determined using high-performance gel permeation chromatography: MA1 (2.3 kDa), MA2 (80.5 kDa), MA3 (180.9 kDa), and MA4 (635.2 kDa), and their compositions were analyzed using GC-MS. The polysaccharides were mainly D-glucose, D-galactose, L-Rhamnose, D-arabinose, D-xylose, and D-mannose. The structural characteristics were further analyzed using infrared spectrophotometry and were identified as a type of pyrrhic sugar. An insulin-induced insulin resistance model of HepG2 cells and oleic acid-induced fat accumulation model of insulin were established to evaluate the hypolipidemic effects. Three Bacteroides spp. [Bacteroides thetaiotaomicron (BT), B. ovatus (BO), and B. cellulosilyticus (BC)] that were negatively correlated with lipid-lowering activity were used to evaluate the lipid-lowering activity of polysaccharides. The Bacteroides metabolites of MA1 and MA2 exhibited hypolipidemic effects and antioxidant activities and could potentially be used as lipid-lowering supplements.

H-Bonds Enhanced Natural Polyphenols Bined Polysaccharide/Gelatin Composites with Controlled Photothermal Stimulation Phase Transition for Wound Care

Severe open wounds should be closed immediately and regularly undergo re-examination and debridement. Therefore, dressings should effectively cover the wound, creating a moist environment for healing while meeting mechanical requirements for daily movement and adaptability. Herein, a low-cost and easy-to-prepare plant polysaccharide hydrogel was reported. The Mesona chinensis Benth polysaccharide strengthened the hydrogel network by hydrogen bonding and changed the phase transition temperature, but retained the thermal response characteristics of the hydrogel. By adjusting the polysaccharide concentration, MepGel(1) can be prepared to remain stable as a semisolid at body temperature and transform into a shear-thinning semifluid state when appropriately heated. The composite hydrogel could be easily shaped, effectively closing wounds of different shapes, while maintaining excellent mechanical properties. Importantly, this composite hydrogel had a near-infrared photothermal effect resulting in excellent antibacterial effect and collided with its own thermal response producing functions conducive to wound care, like accelerating the self-healing of the dressing, achieving re-adhesion, and further covering the wound. Furthermore, the hydrogel had excellent biocompatibility, enhancing immunity and promoting healing of bacterial-infected wounds. The low cost and rich functionality demonstrated by MepGel had the potential to face the enormous challenges and economic burden of clinical wound healing.

Positive effects of extracellular polysaccharides from Paecilomyces hepiali on immune-enhancing properties by regulating gut microbiota in cyclophosphamide-induced mice

Paecilomyces hepiali is a precious health-care edible medicinal fungus with rich polysaccharides and exhibits various biological activities. Polysaccharides from P. hepiali fermentation broth (PHP) exhibits good immunomodulatory activity; however, the mechanism underlying PHP-mediated regulation of immunity and gut microbiota remains unclear. To reveal the mechanisms, PHP of different doses were used to intervene cyclophosphamide (CTX)-induced immunosuppressive model mice. The results revealed that PHP facilitated the secretion of serum cytokines, increased the mRNA and protein expression of TLR4/NF-κB signaling pathway. Furthermore, it improved the physical barrier function of the intestine by upregulating the expression of tight junction proteins. PHP increased the proliferation of beneficial bacteria, including, Actinobacteriota, Alistipes, Candidatus_Saccharimonas and unclassified_Clostridia_vadinBB60_group, and reduced the abundance of Proteobacteria, Deferribacterota, Mucispirillum and Escherichia_Shigella, promoted the production of short-chain fatty acids, which were positively associated with immune traits. Thus, as an immune enhancer, PHP has the potential to regulate the intestinal immune response in immunosuppressed mice through modulating gut microbiota.

Natural polysaccharides and their derivatives targeting the tumor microenvironment: A review

Polysaccharides have gained attention as valuable supplements and natural medicinal resources, particularly for their anti-tumor properties. Their low toxicity and potent anti-tumor effects make them promising candidates for cancer prevention and treatment. The tumor microenvironment is crucial in tumor development and offers potential avenues for novel cancer therapies. Research indicates that polysaccharides can positively influence the tumor microenvironment. However, the structural complexity of most anti-tumor polysaccharides, often heteropolysaccharides, poses challenges for structural analysis. To enhance their pharmacological activity, researchers have modified the structure and properties of natural polysaccharides based on structure-activity relationships, and they have discovered that many polysaccharides exhibit significantly enhanced anti-tumor activity after chemical modification. This article reviews recent strategies for targeting the tumor microenvironment with polysaccharides and briefly discusses the structure-activity relationships of anti-tumor polysaccharides. It also summarises the main chemical modification methods of polysaccharides and discusses the impact of chemical modifications on the anti-tumor activity of polysaccharides. The review aims to lay a theoretical foundation for the development of anti-tumor polysaccharides and their derivatives.

Noni enhances the anticancer activity of cyclophosphamide and suppresses myelotoxicity and hepatotoxicity in tumor-bearing mice

BACKGROUND AND AIM

Morinda citrifolia fruit juice (noni) is an herbal remedy documented to have antioxidant properties. It has been suggested that prevention of carcinogen-DNA adduct formation and the antioxidant activity of NJ may contribute to the cancer preventive effect. In the present study, the antitumor activity of noni was investigated in the presence of cyclophosphamide (CYL) in vitro and in vivo.

METHODS

In vitro breast cancer cells (MDA-MB-468) were used to measure the percentage of inhibition and the IC50. The in vivo antitumor activity of noni was studied by monitoring the mean survival time (MST), percentage increase in life span (%ILS), viable and non-viable cell count, tumor volume, body weight, and hematological and serum biochemical parameters in mice. Treatment with noni and CYL exhibited dose- and time-dependent cytotoxicity toward breast cancer cells.

RESULTS

Individual treatment of noni and CYL exhibited dose- and time-dependent cytotoxicity on breast cancer cell lines, while in combination therapy of noni and CYL, noni enhances cytotoxic effect of CYL at 48 h than that at 24 h. Similar result was found in in vivo studies, the results of which revealed that alone treatment of CYL and noni suppressed tumor growth. However, combination treatment with CYL and noni presented better tumor inhibition than that of alone treatment of CYL and noni. On the contrary, CYL alone drastically attenuated hematological parameters, i.e., RBC, WBC, and Hb compared to normal and control groups, and this change was reversed and normalized by noni when given as combination therapy with CYL. Moreover, the levels of serum biochemical markers, i.e., AST, ALP, and ALT, were significantly increased in the control and CYL-treated groups than those in the normal group. In the combination treatment of noni and CYL, the above biochemical marker levels significantly decreased compared to CYL alone-treated group.

CONCLUSIONS

The present study suggested that CYL treatment can cause serious myelotoxicity and hepatic injury in cancer patients. In conclusion, the combined use of noni with CYL potentially enhances the antitumor activity of CYL and suppresses myelotoxicity and hepatotoxicity induced by CYL in tumor-bearing mice.

Antioxidant stability and in vitro digestion of β-carotene-loaded oil-in-water emulsions stabilized by whey protein isolate-Mesona chinensis polysaccharide conjugates

The aim of this study was to investigate the delivery of functional factor β-carotene by emulsion stabilized with whey protein isolate-Mesona chinensis polysaccharide (WPI-MCP) conjugate. Results showed that the WPI-MCP complex had better antioxidant properties than WPI. Correspondingly, the emulsions stabilized by this complex also had better oxidative stability compared with protein emulsions alone. The particle size of WPI-MCP emulsion was smaller and had a better stability when MCP was added at 0.2 % (w/v). The sizes of WPI-MCP and WPI emulsions were 3594.33 and 7765.67 nm at pH 4, indicating improved emulsion stability around isoelectric point of WPI. At different NaCl concentrations, the absolute values of zeta-potential of WPI-MCP emulsions were larger than that of WPI emulsions except 0.1 % (mol/L) NaCl. The sizes of WPI and WPI-MCP emulsions were 2384.32 and 790.12 nm, respectively. During in vitro digestion, WPI-MCP stabilized emulsions slowed down the release of free fatty acids and achieved about 80 % bioaccessibility of β-carotene, indicating that WPI-MCP-stabilized emulsions encapsulating β-carotene can effectively control the release of bioactive substances. These studies have potential significance and value for the construction of food-grade emulsion delivery system.

Unraveling the bioactive interplay: seaweed polysaccharide, polyphenol and their gut modulation effect

Seaweed is rich in many unique bioactive compounds such as polyphenols and sulfated polysaccharides that are not found in terrestrial plant. The discovery of numerous biological activities from seaweed has made seaweed an attractive functional food source with the potential to be exploited for human health benefits. During food processing and digestion, cell wall polysaccharide and polyphenols commonly interact, and this may influence the nutritional properties of food. Interactions between cell wall polysaccharide and polyphenols in plant-based system has been extensively studied. However, similar interactions in seaweed have received little attention despite the vast disparity between the structural and chemical composition of plant and seaweed cell wall. This poses a challenge in extracting seaweed bioactive compounds with intact biological properties. This review aims to summarize the cell wall polysaccharide and polyphenols present in brown, red and green seaweed, and current knowledge on their potential interactions. Moreover, this review gives an overview of the gut modulation effect of seaweed polysaccharide and polyphenol.

A branched 2-O sulfated 1,3-/1,4-galactoglucan from Antrodia cinnamomea exhibits moderate antiproliferative and anti-inflammatory activities

A sulfated galactoglucan (3-SS) was discovered in Antrodia cinnamomea with antiproliferative and anti-inflammatory activities. Chemical identification of 3-SS resulted in the determination of a partial repeat unit as a 2-O sulfated 1,3-/1,4-linked galactoglucan with a two-residual 1,6-O-β-Glc branch on the 3-O position of a Glc. by monosaccharide analysis and 1D and 2D NMR spectroscopy. The anti-inflammation effects of 3-SS on RAW264.7 macrophage cells, such as IL-6 inhibition, restoration of LPS-induced IκB protein degradation, and inhibited LPS-induced TGFRII protein degradation, were confirmed to occur via AKT, ERK1/2, and p-38. In addition, 3-SS impaired the proliferation of H1975 lung cancer cells through EGFR/ERK/slug signaling. This is the first finding of 2-O sulfated 1,3-/1,4-galactoglucan with 1,6-β-Glc branches with dual functions of anti-inflammatory and antiproliferative activities.

Anti-Inflammatory Effects of Polyphenols from Plum (Prunus salicina Lindl) on RAW264.7 Macrophages Induced by Monosodium Urate and Potential Mechanisms

Acute gouty arthritis is an acute inflammatory reaction caused by the deposition of monosodium urate (MSU) crystals in joints and surrounding soft tissues. Controlling inflammation is the key to preventing acute gouty arthritis. Anti-inflammatory activities and the possible molecular mechanisms of plum (Prunus salicina Lindl cv. "furong") polyphenols (PSLP) on RAW264.7 macrophage cells induced by monosodium urate were investigated. PPSF significantly inhibited the activity of inflammatory factors such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-18 (IL-18). In addition, PPSF exhibited excellent activation of superoxide dismutase (SOD) activity and reduction of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) levels in RAW264.7 macrophages. The results of global screening of all transcripts by RNA-seq revealed 8585 differentially expressed genes between the PSLP-treated group and the MUS group. From GO analysis, PSLP could affect the occurrence and development of RAW264.7 macrophage inflammation through biological processes, such as organic substance metabolism, intracellular organelles, and binding function. The regulation mechanism of PSLP on MSU-induced RAW264.7 macrophage inflammation may be achieved through the HIF-1 signaling pathway, renal cell carcinoma, the ErbB signaling pathway, and the FoxO signaling pathway. Therefore, PSLP has great prospects in the prevention of gout and similar inflammatory diseases.

Immunomodulatory Effects of Chicken Soups Prepared with the Native Cage-free Chickens and the Commercial Caged Broilers

The objective of this study was to compare the immunomodulatory effects of the chicken soups prepared with the native free-range chickens and the commercial caged broilers in the immunosuppressive mice. The immunosuppressive mice model was established by the intraperitoneal injection of 100 mg of cyclophosphamide (CTX) per kg body weight. The powders of Gushi Chicken Soup (GCS), Honglashan Chicken Soup (HCS), and Cobb Broiler Soup (CBS) were prepared by high-pressure stewing followed by spray drying. The chicken soups' nutrient content and the effects of three chicken soups on the body weight, organ index, blood index, and serum cytokine and immunoglobulin contents in the immunosuppressive mice were determined. The three chicken soups promoted the recovery of immunosuppressive mice, but the expression mechanisms were different. The GCS was more effective than the HCS and CBS in restoring blood index, promoting cytokine secretion, and increasing immunoglobulin content (P < 0.05). The HCS stimulated the Th1-type immune response and promoted immunoglobulin secretion (P < 0.05), while the CBS increased the production of CD4⁺ and promoted the T-cell functions better than other soups (P < 0.05). Although soups from the native free-range chickens and the commercial caged broilers showed distinctly different mechanisms in promoting immunity, both could be used as potential immunomodulators.

The regulating effect of Tibet Opuntia ficus-indica (Linn.) Mill. polysaccharides on the intestinal flora of cyclophosphamide-induced immunocompromised mice

The stem of Opuntia species, a traditional medicinal plant, is widely used as food and functional raw material because of its rich polysaccharide content. There have been many studies on the immune function of polysaccharides from Opuntia stem, but only few have examined this function with respect to intestinal microbes. In this study, the effects of different concentrations of Opuntia stem polysaccharides on the immunity and intestinal microflora of cyclophosphamide (CTX)-induced immunocompromised mice were explored. The results showed that Tibet Opuntia ficus-indica (Linn.) Mill. polysaccharides (ODPs) could effectively increase the white blood cells (WBC) count index of mice and improve their thymus and spleen indices, while effectively promoting the secretion of IL-4, IL-1β, TNF-α and IFN-γ, with these effects being dependent on the concentration of crude polysaccharides. The intake of ODPs significantly regulated the relative abundance of Lactobacillus, Bacteroides and Akkermansia, and the new dominant intestinal bacterial species were Deferribacteres, Actinomycetes, Firmicutes, Tenericutes, Actinomycetes and Pasteurella. In addition, the ODPs could effectively enhance the metabolic level of lysine synthesis and decomposition, regulate the gene expression level after immune disorders, and enhance the overall health of the immunodeficient mice.

Sulfated modification enhances the immunomodulatory effect of Cyclocarya paliurus polysaccharide on cyclophosphamide-induced immunosuppressed mice through MyD88-dependent MAPK/NF-κB and PI3K-Akt signaling pathways

The present study investigated the effect of sulfation on the immunomodulatory effect of Cyclocarya paliurus polysaccharide (CP) through a Cyclophosphamide (CTX)-induced immunosuppression mice model. The results showed that sulfated Cyclocarya paliurus polysaccharide (SCP3) had stronger immunomodulatory ability than CP. Administration of SCP3 alleviated immune organ atrophy and restored hematopoiesis in immunosuppressed mice, enhanced splenocyte proliferation, and promoted cytokines and nitric oxide (NO) production in splenocyte supernatants, as well as the number of CD3+, CD4+ and CD8+ T lymphocytes. Meantime, SCP3 significantly improved oxidative stress via increasing the activities of antioxidant enzymes and decreasing the levels of malondialdehyde (MDA) in liver. In addition, SCP3 significantly upregulated the phosphorylation expression of JNK, Erk 1/2, p38 of MAPKs signaling pathway at a dose of 50 mg/kg and accordingly showed increased phosphorylation of Akt, NF-κB (p65), IκB-α, and promoted the degradation of IkB-α. Furthermore, SCP3 significantly increased the expression of the upstream signaling molecule MyD88. All results demonstrated that sulfation can be an effective way to enhance the immunomodulatory effect of polysaccharides. SCP3 has high potential to be a functional food supplement candidate for alleviating chemotherapy drug-induced immunosuppression.

Immunomodulatory Activity of Carboxymethyl Pachymaran on Immunosuppressed Mice Induced by Cyclophosphamide

The effects of immunomodulatory activity of two types of carboxymethyl pachymaran (CMP-1 and CMP-2) on cyclophosphamide (CTX)-induced mice were investigated. Both CMP-1 and CMP-2 were found to restore the splenomegaly and alleviate the spleen lesions and the mRNA expressions of TLR4, MyD88, p65 and NF-κB in spleen were also increased. CMP-1 and CMP-2 could enhance the immunity by increasing the levels of TNF-α, IL-2, IL-6, IFN-γ, Ig-A and Ig-G in serum. In addition, CMP-1 could increase the relative abundance of Bacteroidetes and reduce the relative richness of Firmicutes at the phylum level. CMP-1 and CMP-2 could reduce the relative abundance Erysipelatoclostridum at the genus level. CMP-1 and CMP-2 might enhance the immune function of immunosuppression mice by regulating the gene expression in the TLR4/NF-κB signaling pathway and changing the composition and abundance of the intestinal microbiota. The results suggested that CMP-1 and CMP-2 would be as potential immunomodulatory agents in functional foods.

Chemically Sulfated Polysaccharides from Agaricus blazei Murill: Synthesis, Characterization and Anti-HIV Activity

AIDS, caused by HIV-1, is one of the most dangerous infectious diseases in the world. Therefore, it is necessary to develop new drugs with more potent bioactivities, less toxicity and higher tolerability for controlling the viral load, particularly by using the raw materials that are widely available. Agaricus blazei Murill (AbM), known in China as jisongrong, is of great importance as a food source and as a health-promoting supplement for immunomodulation. The polysaccharides of AbM exhibit various biological activities, such as regulating cellular immunity and providing anti-oxidative, anti-infective, and anti-inflammatory effects. At present, to our knowledge, no report has explored the chemically sulfated and anti-HIV-1 activity of AbM polysaccharides. Herein, the sulfated AbM polysaccharides with different sulfur contents were prepared by the chlorosulfonic acid-pyridine method. The characteristics of sulfated derivatives were established by the determination of the sulfur content, the relative molecular weight, and the Fourier-transform infrared spectroscopy. The anti-HIV activities of the sulfated AbM polysaccharides were evaluated by CCK-8 and the single-cycle pseudovirus infection (TZM-bl) assay. The sulfated AbM polysaccharides had strong antiviral properties, and the half-maximal inhibitory concentrations approached that of the positive control, azidothymidine. Sulfated modification of AbM polysaccharides can increase their anti-HIV pharmacological activity, which makes them promising alternative candidates as bioactive macromolecules for biomedical applications in HIV/AIDS.

Antidiabetic and Nephroprotective Effects of Polysaccharide Extract from the Seaweed Caulerpa racemosa in High Fructose-Streptozotocin Induced Diabetic Nephropathy

BACKGROUND

Nephropathy is a frontline complication of diabetes mellitus (DM) associated with impaired redox-inflammatory networks. The study investigated the antidiabetic and nephroprotective potentials of PCR against diabetic nephropathy (DN) in rats.

METHODS

DN was induced in rats using a combination of a high fructose solution for 4 weeks and an intraperitoneal injection of streptozotocin (35 mg/kg). Diabetic rats were treated with PCR (100 and 400 mg/kg body weight) for 8 weeks. Serum biochemical parameters as well as renal oxidative stress parameters, proinflammatory cytokines, Western blot and histopathological analyses were evaluated.

RESULTS

There were significant increases in fasting blood glucose, urinary albumin, serum creatinine, blood urea nitrogen (BUN), total cholesterol (TC), triglycerides (TG), and low-density lipoproteins (LDL-C) levels in diabetic rats compared to the non-diabetic control rats. DM-induced DN prominently depressed renal superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities, whereas renal malondialdehyde (MDA) level was markedly increased. Furthermore, renal inflammatory cytokines, IL-1β, IL-6, TNF-α and TGF-β, were considerably elevated compared to non-diabetic control rats. Additionally, DN rats showed a significant increase in renal fibrosis, as evidenced by increased expression of TGF-β1, collagen-1, fibronectin and alpha-smooth muscle actin (α-SMA) in the kidneys. Histopathological lesions were consistent with tubule thickening and glomerular hypertrophy. Conversely, PCR treatment exerted significant attenuation of hyperglycemia, dyslipidemia and renal oxidative stress indicators. The increased renal levels of IL-1β, IL-6, TNF-α and TGF-β were also notably reversed dose-dependently with alleviation of nephropathic histology. Furthermore, PCR reduced the expression of α-SMA, fibronectin, collagen-1 and TGF-β1 in the renal tissues.

CONCLUSION

Our results suggest that PCR displayed antidiabetic and nephroprotective effects against DN by impeding oxidative stress and inflammation. As such, PCR has potentials as a food supplement for alleviating renal dysfunction caused by diabetes.