Protective effect of chitooligosaccharides against cyclophosphamide-induced immunosuppression in mice

Therapeutic effect of notoginseng saponins before and after fermentation on blood deficiency rats

Notoginseng saponins (NS) are the active ingredients in Panax notoginseng (Burk.) F.H. Chen (PN). NS can be transformed depending on how the extract is processed. Fermentation has been shown to produce secondary ginsenosides with increased bioavailability. However, the therapeutic effect of fermented NS (FNS) requires further study. The present study compared the compositions and activities of FNS and NS in blood deficiency rats, which resembles the symptoms of anemia in modern medicine, induced by acetylphenylhydrazine and cyclophosphamide. A total of 32 rats were randomly divided into control, model, FNS and NS groups. A blood deficiency model was established and then treatment was orally administered for 21 days. The results of component analysis indicated that some saponins transformed during the fermentation process resulting in a decrease of notoginsenoside R1, and ginsenosides Rg1, Rb1 and Re, and an increase in ginsenosides Rd, Rh2, compound K, protopanaxadiol and protopanaxatriol. The animal results showed that both FNS and NS increased the number of white blood cells (WBCs), red blood cells, hemoglobin, platelets and reticulocytes, and the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin (EPO) and thrombopoietin (TPO), decreased the G0/G1 phase and increased G2/M phase, and decreased the apoptosis rate of bone marrow (BM) cells, which suggested a contribution to the recovery of hematopoietic function of the BM cells. FNS and NS increased the protein expression levels of the cytokines IL-4, IL-10, IL-12, IL-13, TGF-β, IL-6, IFN-γ and TNF-α, and the mRNA expression levels of transcription factors GATA binding protein 3 and T-box expressed in T cell (T-bet). FNS and NS treatment also increased the number of CD4+ T cells, and decreased the enlargement of the rat spleen and thymus atrophy, which indicated a protective effect on the organs of the immune system. The results of the present study demonstrated that compared with NS, FNS showed an improved ability to increase the levels of WBCs, lymphocytes, GM-CSF, EPO, TPO, aspartate aminotransferase, IL-10, IL-12, IL-13 and TNF-α, and the mRNA expression levels of T-bet, and decrease alanine aminotransferase levels. The differences seen for FNS treatment could arise from their improved bioavailability compared with NS, due to the larger proportion of hydrophobic ginsenosides produced during fermentation.

Enhancing immune response, antioxidant capacity, and gut health in growing beagles through a chitooligosaccharide diet

Chitooligosaccharides (COS) have attracted significant attention due to their unique biological activities, water solubility, and absorbable properties. The objective of the present study was to investigate the impact of COS-supplemented diets on the immune response, antioxidative capacity, hematology, serum biochemistry, and modulation of intestinal microbiota in growing beagles. Twelve weaning male beagles (6 weeks old; weighing 3.6 ± 0.6 kg) were fed either a control diet (food without COS, n = 6) or a COS-supplemented diet (n = 6) twice daily for 7 weeks. Blood samples collected at weeks 4 and 7 indicated that hematology and serum biochemistry remained unaffected by COS supplementation. Compared with the control group, the test group showed higher levels of serum antibodies against the canine distemper virus and parvovirus, higher levels of immunoglobulin A, G, and M, and increased activities of superoxide dismutase, glutathione peroxidase, and catalase. In addition, COS was observed to modulate the intestinal flora by enhancing the presence of probiotics, such as Muribaculaceae, Prevotellaceae_Ga6A1_group, Lactobacillus, Collinsella, Blautia, and Lachnospiraceae_NK4A136_group. In summary, a COS-supplemented diet could effectively improve dog health by regulating immune function and antioxidant responses and modulating intestinal microbiota. This study highlights the potentiality of using COS as a valuable nutraceutical for growing dogs.

Chitosan oligosaccharide suppresses osteosarcoma malignancy by inhibiting CEMIP via the PI3K/AKT/mTOR pathway

Osteosarcoma is a malignant bone tumor that is prone to metastasize early and primarily affects children and adolescents. Cell migration-inducing protein (CEMIP) plays a crucial role in the progression and malignancy of various tumor diseases, including osteosarcoma. Chitosan oligosaccharide (COS), an oligomer isolated from chitin, has been found to have significant anti-tumor activity in various cancers. This study investigates the effects of COS on CEMIP expression in osteosarcoma and explores the underlying mechanism. In present study, in vitro experiments were conducted to confirm the inhibitory activity of COS on human osteosarcoma cells. Our results demonstrate that COS possesses inhibitory effects against human osteosarcoma cells and significantly suppresses CEMIP expression in vitro. Next, we studied the inhibition of the expression of CEMIP by COS and then performed bioinformatics analysis to explore the potential inhibitory mechanism of COS against signaling pathways involved in regulating CEMIP expression. Bioinformatics analysis predicted a close association between the PI3K signaling pathway and CEMIP expression and that the inhibitory effect of COS on CEMIP expression may be related to PI3K signaling pathway regulation. The results of this study show that COS treatment significantly inhibits CEMIP expression and the PI3K/AKT/mTOR signaling pathway, as observed both in vitro and in vivo. This study demonstrates that COS could inhibit the expression of CEMIP, which is closely related to osteosarcoma malignancy. This inhibitory effect may be attributed to the inhibition of the PI3K/AKT/mTOR signaling pathway in vitro and in vivo.

Effect of Momordica charantia polysaccharide on immunomodulatory activity in mice

Momordica charantia polysaccharides (MCPs) have been reported to exert beneficial roles, such as disease healing, in medicine and pharmacy. However, little is known about their effects on immunomodulation. The present study aimed to explore the possible effects of Momordica charantia polysaccharide (MCP) on the immunomodulatory activity of mice lymphocytes. To this aim, male BALB/c mice aged 6-8 weeks were assigned to the following six experimental groups: i) Normal (NG); ii) model (MG); iii) positive (PG); iv) MCP low-dose (MLG); v) MCP medium-dose (MMG); and vi) MCP high-dose (MHG). An immunosuppressive model was established by the intraperitoneal injection of cyclophosphamide in all groups apart from NG. The NG and MG mice were fed with distilled water, whereas the PG mice were administered with levamisole and the MLG, MMG and MHG mice were fed on low, medium and high (100, 200 and 300 mg/kg, respectively) doses of MCP for 21 consecutive days. Subsequently, the mice underwent surgical procedure and were analysed using a range of procedures, including measurement of the thymus index (TI) and spleen index (SI), assessment of the lymphocyte proliferation rate and cell phagocytosis of peritoneal macrophages, lymphocyte proliferation, secretion and mRNA expression of cytokines IFN-γ, IL-6 and IL-12. The mice divided into six groups as mentioned above and treated for 7 days, in the first 6 days, except NG group, mice in each group were desiccated in the abdominal cavity and sensitized by 1% dinitrofluorobenzene (DNFB). On day 6, mice were sensitized with 20 µl DNFB/acetone/olive oil solution behind the right ear and in front of the right ear. Compared with those in the NG mice (not injected with 80 mg/kg cyclophosphamide), the TIs and SIs of the PG, MLG, MMG and MHG mice were increased. In addition, the inhibitory rate of ear swelling and the phagocytic activity of peritoneal macrophages in the PG, MLG, MMG and MHG mice were increased compared with those of MG. Furthermore, the lymphocyte proliferation rate, the secretion and relative mRNA expression levels of cytokines IFN-γ, IL-6 and IL-12 were significantly increased in the PG, MMG and MHG mice compared with those in the NG mice. The results from the present study suggest that treatment with MCP led to an upregulation of the organ indices of immunosuppressed mice, reduced their delayed allergic reaction indicated by the differential cytokine levels, improved the phagocytic activity of peritoneal macrophages, enhanced the proliferation rate of lymphocytes, increased the secretion and expression of IFN-γ, IL-6 and IL-12. Therefore, MCP may improve the immune function of the immunosuppressed mice.

Phosphate-modified cellulose/chitosan with high drug loading for effective prevention of rice leaffolder (Cnaphalocrocis medinalis) outbreaks in fields

The continuous infestation of pests has seriously affected rice growth, yield and quality. How to reduce the use of pesticides and effectively control insect pests is a bottleneck problem. Herein, based on hydrogen bonding and electrostatic interactions, we posed a novel strategy to construct emamectin benzoate (EB) pesticide loading system using self-assembled phosphate-modified cellulose microspheres (CMP) and chitosan (CS). CMP provides more binding sites for EB loading and CS coating further enhances the carrier loading capacity up to 50.75 %, which jointly imparted pesticide photostability and pH-responsiveness. The retention capacity of EB-CMP@CS in rice growth soil reached 101.56-fold that of commercial EB, which effectively improved the absorption of pesticides during rice development. During the pest outbreak, EB-CMP@CS achieved effective pest control by increasing the pesticide content in rice stems and leaves, the control efficiency of the rice leaffolder (Cnaphalocrocis medinalis) reached 14-fold that of commercial EB, and could maintain the effective pest control effect during the booting stage of rice. Finally, EB-CMP@CS-treated paddy fields had improved yields and were free of pesticide residues in the rice grain. Therefore, EB-CMP@CS achieves effective control of rice leaffolder in paddy fields and has potential application value in green agricultural production.

Immunomodulatory effects and mechanisms of Tiepishihu Xiyangshen granules on cyclophosphamide induced immuno-suppression via TLR4/MAPKs and PI3K/AKT/FOXO3a signal pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Tiepishihu Xiyangshen granules (TXG) is a traditional Chinese medicine formula composed of Panax quinquefolius L, Dendrobium officinale Kimura & Migo and Ganoderma lucidum (Curtis) P. Karst. It has long been used as a nutritional supplement and an immune enhancer in China. However, the immunomodulatory effects and the underlying mechanisms of TXG have not been clarified.

AIM OF THE STUDY

This study aims to investigate the immunomodulatory effects of TXG and clarify the underlying mechanism.

MATERIALS AND METHOD

TXG was administered by gavage for 18 days. From the 15th day, the immunosuppression model was induced by intraperitoneally injecting 80 mg/kg CTX for 3 days. The immune regulatory effects of TXG on immune organs were verified by calculating the organ index and observing the spleen tissue structure through HE staining. The effects of TXG on immune cells were examined by recording the PBWC, the proliferation rate of lymphocyte and the T lymphocyte phenotype. The effects of TXG on immune molecules were measured by detecting serum hemolysin and the content of cytokines. In parallel, kit was utilized to detect its antioxidant capacity. RNA seq and Western blot were used to analyze the possible immune regulation mechanism of TXG. HPLC and UPLC-Q-TOF-MS were used to identify the chemical components in TXG.

RESULTS

At the level of immune organs, TXG effectively reduced the adverse reaction to the body and the substantial damage to the spleen after chemotherapy by improving the spleen damage. At the level of immune molecules, TXG upregulated the expression of cytokines and antibodies. At the level of immune cells, TXG antagonized bone marrow suppression by increasing the PBWC of immunosuppressed mice. Meanwhile, TXG upregulated the ratio of CD4⁺/CD8⁺ lymphocytes and ameliorated the proliferation of T and B lymphocytes. And the mechanism of TXG to improve immunity might be through TLR4/MAPKs and PI3K/AKT/FOXO3a signaling pathways.

CONCLUSION

The results of this study confirmed that TXG has prominent immunomodulatory activities, and the immunity regulations of TXG may be achieved by regulating TLR4/MAPKs and PI3K/AKT/FOXO3a signal pathways.

Structural characterization of a sulfated polysaccharide from Ishige okamurae and its effect on recovery from immunosuppression

A sulfated polysaccharide from the brown alga Ishige okamurae Yendo, designated IOY, was successfully isolated by anion-exchange and size-exclusion chromatography. Chemical and spectroscopic analyses demonstrated that IOY was a fucoidan, that consisted of →3)-α-l-Fucp-(1→, →4)-α-l-Fucp-(1→, →6)-β-d-Galp-(1 → and →3)-β-d-Galp-(1 → residues with sulfate groups at C-2/C-4 the of (1 → 3)-α-l-Fucp and C-6 the of (1 → 3)-β-d-Galp residues. IOY possessed a potent immunomodulatory effect in vitro as measured by lymphocyte proliferation assay. The immunomodulatory effect of IOY was further investigated in vivo using immunosuppressed mice induced by cyclophosphamide (CTX). The results showed that IOY significantly increased the spleen and thymus indexes and alleviated CTX-induced spleen and thymus damage. Furthermore, IOY had a significant effect on hematopoietic function recovery and promoted the secretion of interleukin-2 (IL-2) and tumor necrosis factor (TNF-α). Notably, IOY reversed CD4+ and CD8+ T cell reduction and improved immune response. These data indicated that IOY had vital in immunomodulatory function and could be used as drug or functional food to lessen chemotherapy-induced immunosuppression.

Immunostimulatory effects of dairy probiotic strains Bifidobacterium animalis ssp. lactis HY8002 and Lactobacillus plantarum HY7717

Previous studies reported that Bifidobacterium animalis ssp. lactis HY8002 (HY8002) improved intestinal integrity and had immunomodulatory effects. Lactobacillus plantarum HY7717 (HY7717) was screened in vitro from among 21 other lactic acid bacteria (LAB) and demonstrated nitric oxide (NO) production. The aims of this study were to investigate the individual and combined ex vivo and in vivo effects of LAB strains HY8002 and HY7717 at immunostimulating mice that have been challenged with an immunosuppressant drug. The combination of HY8002 and HY7717 increased the secretion of cytokines such as interferon (IFN)-γ, interleukin (IL)-12, and tumor necrosis factor (TNF)-α in splenocytes. In a cyclophosphamide (CTX)-induced immunosuppression model, administration of the foregoing LAB combination improved the splenic and hematological indices, activated natural killer (NK) cells, and up-regulated plasma immunoglobulins and cytokines. Moreover, this combination treatment increased Toll-like receptor 2 (TLR2) expression. The ability of the combination treatment to upregulate IFN-γ and TNF-α in the splenocytes was inhibited by anti-TLR2 antibody. Hence, the immune responses stimulated by the combination of HY8002 and HY7717 are associated with TLR2 activation. The preceding findings suggest that the combination of the HY8002 and HY7717 LAB strains could prove to be a beneficial and efficacious immunostimulant probiotic supplement. The combination of the two probiotic strains will be applied on the dairy foods including yogurt and cheese.

Potential Medical Applications of Chitooligosaccharides

Chitooligosaccharides, also known as chitosan oligomers or chitooligomers, are made up of chitosan with a degree of polymerization (DP) that is less than 20 and an average molecular weight (MW) that is lower than 3.9 kDa. COS can be produced through enzymatic conversions using chitinases, physical and chemical applications, or a combination of these strategies. COS is of significant interest for pharmacological and medical applications due to its increased water solubility and non-toxicity, with a wide range of bioactivities, including antibacterial, anti-inflammatory, anti-obesity, neuroprotective, anticancer, and antioxidant effects. This review aims to outline the recent advances and potential applications of COS in various diseases and conditions based on the available literature, mainly from preclinical research. The prospects of further in vivo studies and translational research on COS in the medical field are highlighted.

Blood-Enriching Effects and Immune-Regulation Mechanism of Steam-Processed Polygonatum Sibiricum Polysaccharide in Blood Deficiency Syndrome Mice

Polygonatum sibiricum Red. has been used as a medicinal herb and nutritional food in traditional Chinese medicine for a long time. It must be processed prior to clinical use for safe and effective applications. However, the present studies mainly focused on crude Polygonatum sibiricum (PS). This study aimed to investigate the chemical properties, blood-enriching effects and mechanism of polysaccharide from the steam-processed Polygonatum sibiricum (SPS), which is a common form of PS in clinical applications. Instrumentation analyses and chemistry analyses revealed the structure of SPS polysaccharide (SPSP). A mice model of blood deficiency syndrome (BDS) was induced by acetylphenylhydrazine (APH) and cyclophosphamide (CTX). Blood routine test, spleen histopathological changes, serum cytokines, etc. were measured. The spleen transcriptome changes of BDS mice were detected by RNA sequencing (RNA-seq). The results showed that SPSP consists predominantly of Gal and GalA together with fewer amounts of Man, Glc, Ara, Rha and GlcN. It could significantly increase peripheral blood cells, restore the splenic trabecular structure, and reverse hematopoietic cytokines to normal levels. RNA-seq analysis showed that 122 differentially expressed genes (DEGs) were obtained after SPSP treatment. GO and KEGG analysis revealed that SPSP-regulated DEGs were mainly involved in hematopoiesis, immune regulation signaling pathways. The reliability of transcriptome profiling was validated by quantitative real-time PCR and Western blot, and the results indicated that the potential molecular mechanisms of the blood-enriching effects of SPSP might be associated with the regulating of JAK1-STAT1 pathway, and elevated the hematopoietic cytokines (EPO, G-CSF, TNF-α and IL-6). This work provides important information on the potential mechanisms of SPSP against BDS.

Chitin derivatives ameliorate DSS-induced ulcerative colitis by changing gut microbiota and restoring intestinal barrier function

Chitin derivatives (CDs), including chitosan (CS), chitooligosaccharides (COS), and glucosamine (GlcN), were administrated in dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) mice. UC symptoms such as body weight loss, reduced food intake, and increased disease activity index were relieved (except GlcNL group). CDs (except GlcNL) exerted a strong protective effect on colon length and colonic structure. Treatment with CDs (except GlcNL) increased IL-10 level, reduced levels of IL-1β, IL-6, TNF-α, myeloperoxidase, and inducible nitric oxide synthase, and enhanced expression of tight junction proteins significantly. CDs (except GlcNL) significantly upregulated IκB-α level, and downregulated p65 and p38 phosphory lation and TLR-4 mRNA transcription level, indicating inhibition of TRL-4/NF-κB/MAPK signaling pathway activity. CD treatments increased relative abundance of gut microbiota, modulated its composition, and increased the concentrations of SCFAs. Our findings indicate that CDs exert an ameliorative effect on UC by change of gut microbiota composition and restoration of intestinal barrier function.

Expression and Characterization of a Novel Cold-Adapted Chitosanase from Marine Renibacterium sp. Suitable for Chitooligosaccharides Preparation

(1) Background: Chitooligosaccharides (COS) have numerous applications due to their excellent properties. Chitosan hydrolysis using chitosanases has been proposed as an advisable method for COS preparation. Although many chitosanases from various sources have been identified, the cold-adapted ones with high stability are still rather rare but required. (2) Methods: A novel chitosanase named CsnY from marine bacterium Renibacterium sp. Y82 was expressed in Escherichia coli, following sequence analysis. Then, the characterizations of recombinant CsnY purified through Ni-NTA affinity chromatography were conducted, including effects of pH and temperature, effects of metal ions and chemicals, and final product analysis. (3) Results: The GH46 family chitosanase CsnY possessed promising thermostability at broad temperature range (0-50 °C), and with optimal activity at 40 °C and pH 6.0, especially showing relatively high activity (over 80% of its maximum activity) at low temperatures (20-30 °C), which demonstrated the cold-adapted property. Common metal ions or chemicals had no obvious effect on CsnY except Mn2+ and Co2+. Finally, CsnY was determined to be an endo-type chitosanase generating chitodisaccharides and -trisaccharides as main products, whose total concentration reached 56.74 mM within 2 h against 2% (w/v) initial chitosan substrate. (4) Conclusions: The results suggest the cold-adapted CsnY with favorable stability has desirable potential for the industrial production of COS.

Effects of cyclophosphamide on antioxidative and immune functions of Nile tilapia (Oreochromis Niloticus) via the TLR-NF-κB signaling pathway

Intensive aquaculture often results in immunosuppression in fish, which may cause a series of diseases. In this study, to investigate the immunosuppressive mechanisms in fish, tilapia were intrapleural injected cyclophosphamide (CTX) at the doses of 10, 25, 50, 75 and 100 mg·kg^-1 to induce immunosuppression. We determined the viability of immune cells, the content of lysozyme (LZM) and immunoglobulin M (IgM), the levels of nitric oxide (NO) and antioxidant parameters. Meanwhile, the mRNA levels of complement C3 (c3), igm and the genes associated with the TLR-NF-κB signaling pathway in the head kidney (HK) and spleen were also determined. The results showed that CTX had a significant cytotoxic effect on peripheral blood leukocytes, HK macrophages and spleen cells in a dose-dependent manner. The protein and mRNA levels of C3 and IgM were down-regulated with the increase of CTX concentrations in serum, HK and/or spleen. The NO and LZM contents decreased significantly in HK and spleen after CTX treatments with 75 and 100 mg·kg^-1. CTX treatments with 50, 75 and/or 100 mg·kg^-1 markedly decreased the antioxidant ability and enhanced lipid peroxidation in HK and spleen. Furthermore, qPCR data showed that CTX treatments with 50-100 mg·kg^-1 clearly down-regulated the mRNA levels of tlr2, myd88, irak1, traf6, nfκb1, nfκb2, il-6, il-10 and tnf-α in the HK and/or spleen. Overall results suggested that CTX treatment had a cytotoxic effect on immune cells, induced lipid peroxidation, decreased the antioxidant capacity and inhibited immune function. The immunosuppressive mechanisms of CTX may be associated with the TLR-NF-κB signaling pathway.

Fabrication of a Silk Sericin Hydrogel System Delivering Human Lactoferrin Using Genetically Engineered Silk with Improved Bioavailability to Alleviate Chemotherapy-Induced Immunosuppression

Chemotherapy is one of the main treatments for cancer; however, it usually causes severe atrophy of immune organs and self-immunity damage to patients. Human lactoferrin (hLF) is a multiple biofunctional protein in regulating the immune response and thus holds great promise to alleviate chemotherapy-caused immunosuppression. However, a sufficient hLF resource and efficient delivery of hLF remain a challenge. Here, we provide a useful strategy to simultaneously solve these two problems. A silk sericin hydrogel system delivering recombinant hLF (SSH-rhLF) was fabricated to alleviate the chemotherapeutic drug-caused side effects by rhLF-carrying silk cocoons, which were cost-effectively produced by a transgenic silkworm strain as the resource. SSH-rhLF with a uniform porous microstructural morphology, a dominant β-sheet internal structure, adjustable concentration and sustainable release of the rhLF, and non-cytotoxicity properties was demonstrated. Interestingly, the sericin hydrogel showed effective protection of the rhLF from degradation in the stomach and small intestine, thus prolonging the bioactivity and bioavailability of rhLF. As a result, the oral administration of SSH-rhLF with a low rhLF dose showed significant therapeutic effects on enhancing the immune organs of cyclophosphamide (CTX)-treated mice by protecting the splenic follicles, promoting the expression of immunoregulatory factors, and recovering the intestinal flora family from CTX-induced imbalance, which were similar to those achieved by oral administration of a high dose of free hLF in the solution form. The results suggest that the strategy of producing rhLF silk cocoons via feeding transgenic silkworms overcomes well the shortage of rhLF resources, improves the bioavailability of oral rhLF, and alleviates the side effects of chemotherapeutic drugs on immune organs. The oral SSH-rhLF will be promising for applications in cancer chemotherapy and immunity enhancement of patients.

Effects of Lycium barbarum Polysaccharides on Immunity and the Gut Microbiota in Cyclophosphamide-Induced Immunosuppressed Mice

The mechanism of immunoregulation by Lycium barbarum polysaccharides (LBPs) was assessed by studying the effect of LBP on the immunity and the gut microbiota. LBP isolated and purified in this study was composed of nine monosaccharides, with an Mw 1,207 kDa. LBP showed immunomodulatory activity in cyclophosphamide (Cy)-treated mice by restoring the damaged immune organs and adjusting the T lymphocyte subsets. We also found that LBP increased the diversity of the gut microbiota and the relative abundances of bacteria, such as Rickenellaceae, Prevotellaceae, Bifidobacteriaceae, and so on, which were positively associated with immune traits. In addition, Caco2 cells model was used to explore the intestinal absorption of LBP. Results showed that LBP was hardly absorbed in the intestine, which suggesting that most LBP may interact with gut microbiota. These findings suggest that the immune response induced by LBP is associated with the regulation of the gut microbiota.

Preclinical evaluation of methotrexate-loaded polyelectrolyte complexes and thermosensitive hydrogels as treatment for rheumatoid arthritis

This work proposes new methotrexate (MTX) loaded drug delivery systems (DDS) to treat rheumatoid arthritis via the intra-articular route: a poloxamer based thermosensitive hydrogel (MTX-HG), oligochitosan and hypromellose phthalate-based polyelectrolyte complexes (MTX-PEC) and their association (MTX-PEC-HG). MTX-PEC showed 470 ± 166 nm particle size, 0.298 ± 0.108 polydispersity index, +26 ± 2 mV and 74.3 ± 5.8% MTX efficiency entrapment and particle formation was confirmed by infrared spectroscopy and thermal analysis. MTX-HG and MTX-PEC-HG gelled at 36.7°C. MTX drug release profile was prolonged for MTX-HG and MTX-PEC-HG, and faster for MTX-PEC and free MTX. The in vivo effect of the MTX-DDSs systems was evaluated in induced arthritis rats as single intra-articular dose. The assessed parameters were the mechanical nociceptive threshold, the plasmatic IL-1β level and histological analysis of the tibiofemoral joint. MTX-HG and MTX-PEC-HG performance were similar to free MTX and worse than oral MTX, used as positive control. All DDSs showed some irritative effect, for which further studies are required. MTX-PEC was the best treatment on recovering cartilage damage and decreasing allodynia. Thus, MTX-PEC demonstrated potential to treat rheumatoid arthritis, with the possibility of decreasing the systemic exposure to the drug.

Carbon Source Affects Synthesis, Structures, and Activities of Mycelial Polysaccharides from Medicinal Fungus Inonotus obliquus

The effects of various carbon sources on mycelial growth and polysaccharide synthesis of the medicinal fungus Inonotus obliquus in liquid fermentation were investigated. After 12-d fermentation, mycelial biomass, polysaccharide yield, and polysaccharide content were significantly higher in Glc+Lac group (glucose and lactose used as combined carbon source) than in other groups. Crude polysaccharides (CIOPs) and the derivative neutral polysaccharides (NIOPs) were obtained from mycelia fermented using Glc, fructose (Fru), Lac, or Glc+Lac as carbon source. Molecular weights of four NIOPs (termed as NIOPG, NIOPF, NIOPL, and NIOPGL) were respectively 780.90, 1105.00, 25.32, and 10.28 kDa. Monosaccharide composition analyses revealed that NIOPs were composed of Glc, Man, and Gal at different molar ratios. The NIOPs were classified as α-type heteropolysaccharides with 1→2, 1→3, 1→4, 1→6 linkages in differing proportions. In in vitro cell proliferation assays, viability of RAW264.7 macrophages was more strongly enhanced by NIOPL or NIOPGL than by NIOPG or NIOPF, and proliferation of HeLa or S180 tumor cells was more strongly inhibited by NIOPG or NIOPGL than by NIOPF or NIOPL, indicating that immune-enhancing and anti-tumor activities of NIOPs were substantially affected by carbon source. qRT-PCR analysis revealed that expression levels of phosphoglucose isomerase (PGI) and UDP-Glc 4-epimerase (UGE), two key genes involved in polysaccharide synthesis, varied depending on carbon source. Our findings, taken together, clearly demonstrate that carbon source plays an essential role in determining structure and activities of I. obliquus polysaccharides by regulating expression of key genes in polysaccharide biosynthetic pathway.

Advances in the preparation and assessment of the biological activities of chitosan oligosaccharides with different structural characteristics

Chitosan oligosaccharides (COSs) are widely used biopolymers that have been studied in relation to a variety of abnormal biological activities in the food and biomedical fields. Since different COS preparation technologies produce COS compounds with different structural characteristics, it has not yet been possible to determine whether one or more chito-oligomers are primarily responsible for the bioactivity of COSs. The inherent biocompatibility, mucosal adhesion and nontoxic nature of COSs are well documented, as is the fact that they are readily absorbed from the intestinal tract, but their structure-activity relationship requires further investigation. This review summarizes the methods used for COS preparation, and the research findings with regard to the antioxidant, anti-inflammatory, anti-obesity, bacteriostatic and antitumour activity of COSs with different structural characteristics. The correlation between the molecular structure and bioactivities of COSs is described, and new insights into their structure-activity relationship are provided.

Targeting the TLR2 Receptor With a Novel Thymopentin-Derived Peptide Modulates Immune Responses

The innate and adaptive immune systems act in concert to protect us from infectious agents and other harmful substances. As a state of temporary or permanent immune dysfunction, immunosuppression can make an organism more susceptible to infection, organ injury, and cancer due to damage to the immune system. It takes a long time to develop new immunomodulatory agents to prevent and treat immunosuppressive diseases, with slow progress. Toll-like receptor 2 (TLR2) agonists have been reported as potential immunomodulatory candidates due to their effective activation of immune responses. It has been demonstrated that thymopentin (TP5) could modulate immunity by binding to the TLR2 receptor. However, the fairly short half-life of TP5 greatly reduces its pharmacological potential for immunosuppression therapy. Although peptide cathelicidin 2 (CATH2) has a long half-life, it shows poor immunomodulatory activity and severe cytotoxicity, which seriously hampers its clinical development. Peptide hybridization is an effective approach for the design and engineering of novel functional peptides because hybrid peptides combine the advantages and benefits of various native peptides. In this study, to overcome all these challenges faced by the parental peptides, six hybrid peptides (CaTP, CbTP, CcTP, TPCa, TPCb, and TPCc) were designed by combining the full-length TP5 with different active fragments of CATH2. CbTP, the most potent TLR2 agonist among the six hybrid peptides, was effectively screened through in silico analysis and in vitro experiments. The CbTP peptide exhibited lower cytotoxicity than either CATH2 or TP5. Furthermore, the immunomodulatory effects of CbTP were confirmed in a CTX-immunosuppressed mouse model, which showed that CbTP has increased immunopotentiating activity and physiological stability compared to the parental peptides. CbTP successfully inhibited immunosuppression and weight loss, increased immune organ indices, and improved CD4⁺/CD8⁺ T lymphocyte subsets. In addition, CbTP significantly increased the production of the cytokine TNF-α and IL-6, and the immunoglobulins IgA, IgM, and IgG. The immunoenhancing effects of CbTP were attributed to its TLR2-binding activity, promoting the formation of the TLR2 cluster, the activation of the TLR2 receptor, and thus activation of the downstream MyD88-NF-кB signaling pathway.

Chitosan and Derivatives: Bioactivities and Application in Foods

Chitosan is a biodegradable, biocompatible, and nontoxic aminopolysaccharide. This review summarizes and discusses the structural modifications, including substitution, grafting copolymerization, cross-linking, and hydrolysis, utilized to improve the physicochemical properties and enhance the bioactivity and functionality of chitosan and related materials. This manuscript also reviews the current progress and potential of chitosan and its derivatives in body-weight management and antihyperlipidemic, antihyperglycemic, antihypertensive, antimicrobial antioxidant, anti-inflammatory, and immunostimulatory activities as well as their ability to interact with gut microbiota. In addition, the potential of chitosan and its derivatives as functional ingredients in food systems, such as film and coating materials, and delivery systems is discussed. This manuscript aims to provide up-to-date information to stimulate future discussion and research to promote the value-added utilization of chitosan in improving the safety, quality, nutritional value and health benefits, and sustainability of our food system while reducing the environmental hazards.

Design and Immunological Evaluation of a Hybrid Peptide as a Potent TLR2 Agonist by Structure-Based Virtual Screening

Immunity is a versatile defensive response that is involved in protecting against disease by identifying and destroying self and non-self harmful substances. As a state of temporary or permanent immune dysfunction, immunosuppression can make an organism more susceptible to infection, organ injury, and cancer due to damage to the immune system. It has taken a long time to develop new immunomodulatory agents to prevent and treat immunosuppressive diseases. In recent years, Toll-like receptor 2 (TLR2) agonists have been reported to have profound effects on the immune system, and they are regarded as potent immunomodulatory candidates. TP5 and LL-37, the potent immunomodulatory agents, have been reported to produce a robust innate immune response by binding to TLR2. However, their development has been weakened by several concerns, such as potential cytotoxicity, weak physiological stability and poor immunomodulatory activity. To overcome these challenges, hybridization has been proposed. Therefore, six hybrid peptides (LTPa, LTPb, LTPc, TPLa, TPLb, and TPLc) were designed by combining the full-length TP5 with a characteristic fragment of LL-37 that included LL-37 (13-36), LL-37 (17-29), and LL-37 (13-31). LTPa, the most potent TLR2 agonist, was simply and effectively screened by molecular docking and in vitro experiments. Furthermore, the immunomodulatory effects of LTPa were confirmed by a CTX-immunosuppressed murine model, which demonstrated that LTPa successfully inhibit immunosuppression, increased immune organ indices, enhanced DC maturation, regulated T lymphocyte subsets, and increased cytokine and Ig contents. Our study also revealed that the immunomodulatory effects of LTPa are associated with binding to TLR2, forming TLR2 clusters, and activating the NF-κB signaling pathway.

Antithrombin III-mediated blood coagulation inhibitory activity of chitosan sulfate derivatized with different functional groups

Acylated chitosan sulfate (ChS1), a sulfated polysaccharide with high anticoagulant activity, was chemically synthesized and structurally characterized using FT-IR analysis. The beneficial structural properties and high availability of the sulfate group in ChS1 led to greater anticoagulant activity through both the intrinsic and common pathways with antithrombin III (AT III)-mediated inhibition, particularly involving coagulation factors FXa and FIIa. The analysis of the binding affinities using surface plasma resonance found that the equilibrium dissociation constant (K_D) of ChS1 for FXa and FIIa in the presence of AT III was 67.4 nM and 112.6 nM, respectively, indicating the stronger interaction of the AT III/ChS1 complex with the ligands and the inhibition of activated FX and FII. The results of amidolytic assays further demonstrated the stronger inhibition of the proteolytic conversion of factor X by the intrinsic FXase complex and of FII by the prothrombinase complex. Molecular docking analysis further validated the protein-ligand interactions of ChS1 with AT III and their binding affinity.

Research Advances in Chitosan Oligosaccharides: From Multiple Biological Activities to Clinical Applications

Chitosan oligosaccharides (COS), hydrolysed products of chitosan, are low-molecular weight polymers with a positive charge and good biocompatibility. COS have recently been reported to possess various biological activities, including hypoglycaemic, hypolipidaemic, antioxidantantioxidant, immune regulation, anti-inflammatory, antitumour, antibacterial, and tissue engineering activities, exhibiting extensive application prospects. Currently, the biological processes and mechanisms of COS are attractive topics of study, ranging from the genetic, molecular and protein levels. This article reviews the recent discoveries about COS, especially in metabolic regulation, immune function and tissue repair, providing important insights into their multiple biological activities, medical benefits, and therapeutic mechanisms.

Chitosan oligosaccharide combined with running benefited the immune status of rats

Chitosan oligosaccharide (COS) degraded by chitosan, is an easily accessible and biocompatible natural molecule, which can facilitate the immune system. Running is one of the most effective forms of exercise. Persistence in running can effectively improve the body's resistance against pathogens. However, whether the combination of COS and running could benefit immune status still remains to be elucidated. We used Sprague-Dawley (SD) rats to explore the combinatory effect of COS and running. The organs and blood of the rats were collected after four weeks and the organ body mass index, biochemical and blood routine examination, cytokines, and T cells in the spleen and blood were detected and analyzed. In the group intragastric administration of COS only, the level of blood lactate dehydrogenase was increased, while the blood creatinine, red blood cells, lymphocytes, and serum TNF were decreased. Furthermore, COS combined with running promoted the development of spleen and lung, the level of lymphocytes, T cell and CD8⁺ T cell ratio in the blood, and serum TNF level. At the same time, the level of lactate dehydrogenase, serum IL-2, and T cell ratio in spleen were decreased. Therefore, our study indicated that COS combined with running could improve the immune status of rats.

Poplar bark lipids enhance mouse immunity by inducing T cell proliferation and differentiation

Research on the composition and application of immune enhancers in livestock and poultry breeding has been gaining interest in recent years. Poplar bark lipids (PBLs), which are extracted from poplar tree bark, are natural substances known to efficiently enhance the immune response. To understand the chemical makeup of PBLs and their underlying mechanism for enhancing the immune system, we extracted PBLs from poplar bark using petroleum ether and subjected these extracts to chemical analysis. To evaluate PBLs effect on the immune system mice were treated with different doses of PBL via gavage and sacrificed 4 weeks later. PBLs were shown to be rich in vitamin E, unsaturated fatty acids, and other immune-potentiating compounds. Treatment with PBLs increased the spleen index and stimulated spleen and thymus development. In addition, PBLs increased the number of CD3+CD4+ cells in the peripheral blood and the ratio of CD4+/CD8+ cells while decreasing the number of CD3+CD8+ cells. Moreover, PBLs significantly increased IL-4 and IFN-γ levels in mouse serum and TLR4 mRNA and protein expression in the spleen. Taken together these results demonstrate that PBLs exert their immune-potentiating effects by promoting spleen and thymus development, T lymphocyte proliferation and differentiation, and immune factor expression. These immune-potentiating effects may be related to the activation of TLR4. This study provides a theoretical basis for the development of PBLs as an immune adjuvant or feed additive in the future.

Immunomodulatory Activity of Lactococcus lactis GCWB1176 in Cyclophosphamide-Induced Immunosuppression Model

Recently, Lactococcus lactis subsp. lactis has been reported to have immunostimulating properties in an immunosuppressed-animal model. However, the immunological activities of Lactococcus lactis and the molecular mechanisms remain unclear. In this report, we evaluated the immunostimulating activity and associated mechanisms of Lactococcus lactis subsp. lactis GCWB1176 (GCWB1176) in macrophages and cyclophosphamide (CTX)-induced immunosuppressed mice. In a series of safety tests, GCWB1176 was found to have a negative response to hemolysis, as well as susceptibility to antibiotics. Administration of GCWB1176 elevated natural killer (NK) cell activities; concanavalin A-induced T cell proliferation; and serum levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-10 and IL-12 in CTX-induced immunosuppressed mice. In RAW264.7 macrophages, treatment with GCWB1176 induced phagocytic activity and increased the production of nitric oxide (NO) and expression of inducible NO synthase. Simultaneously, GCWB1176 increased the production of TNF-α, IFN-γ, IL-1β, IL-10 and IL-12 from mouse splenocytes and RAW264.7 cells. In addition, GCWB1176 significantly increased the transcriptional activities of NF-κB and iNOS. Taken together, GCWB1176 improved immune function through the activation of macrophages and NK cells. These findings suggest that dietary supplementation of GCWB1176 may be used to enhance immunity.

Novel antifungal mechanism of oligochitosan by triggering apoptosis through a metacaspase-dependent mitochondrial pathway in Ceratocystis fimbriata

The antifungal effects of oligochitosan (OCS) against Ceratocystis fimbriata that causes black rot disease in sweet potato and its apoptosis mechanism were evaluated. OCS restrained the mycelial growth and spores germination of C. fimbriata, and decreased the ergosterol content of cell membrane. Transmission electron microscopy observation and flow cytometry analysis revealed that OCS induced morphology changes with smaller size and increased granularity of C. fimbriata, which was the typical feature of apoptosis. To clarify the apoptosis mechanism induced by OCS, a series of apoptosis-related parameters were analyzed. Results showed that OCS induced reactive oxygen species accumulation, Ca²⁺ homeostasis dysregulation, mitochondrial dysfunction and metacaspase activation, coupled with hallmarks of apoptosis including phosphatidylserine externalization, DNA fragmentation, and nuclear condensation. In summary, OCS triggered apoptosis through a metacaspase-dependent mitochondrial pathway in C. fimbriata. These findings have important implications for the application of OCS to control pathogens in food and agriculture.

Quality control and immunological activity of lentinan samples produced in China

Lentinan is widely used as a therapeutic agent for treatment of malignant tumors in clinical practice. The chemical structure of lentinan is highly associated with its biological activity. In this study, the correlation between the structure of lentinan and its immune activity was investigated to assess the function of key parameters that can influence quality control of lentinan. The results showed that the batch-to-batch consistency of two lentinan samples was satisfactory, indicating the stability of production process of lentinan. However, although the chemical composition and triple-helical conformation (THC) of the tested samples were relatively similar, their Mw, polydispersity index (PDI), and Rg_z remarkably varied due to different production processes. In vitro immunomodulatory assay reflects that lentinan could stimulate the macrophages phagocytic capacity. Meanwhile, lentinan samples could improve the spleen and thymus indices, promote the proliferation of lymphocytes and adjust for the percentages of CD4+ and CD8+ T cells in vivo. Furthermore, the immunomodulatory effect of lentinan sample B (Mw: 650,700 g/mol) was superior than that of the sample A (Mw: 4,818,700 g/mol). It was noted that the Mw should be detected as a necessary index for quality control of lentinan to ensure stability and effectiveness of the production process.

Zwitterionic chitooligosaccharide-modified ink-blue titanium dioxide nanoparticles with inherent immune activation for enhanced photothermal therapy

Photothermal therapy (PTT) can trigger massive apoptosis of cancer cells, and this sharply increasing local apoptotic rate may recruit plenty of tumor-associated macrophages (TAMs). Although TAMs are recognized to display an M2-like subtype, which encourages tumor ontogenesis, they can be re-educated to a tumoricidal M1-like subtype by immunomodulatory reagents. Chitooligosaccharides (COSs) are endowed with immunomodulatory ability, but the positive electrical property limits their application; besides, their re-educating ability on TAMs is uncertain. Therefore, we proposed whether the combination of zwitterionic COS with a photothermal material can impair the undesirable tumor promotion of TAMs, thus enhancing the PTT treatment outcome. Herein, zwitterionic COS was obtained via the carboxymethylate method and then, the obtained COS was modified on the surface of ink-blue titanium dioxide (BTiO2) with photothermal ability to synthesize BTC NPs. In vitro, the immunofluorescence staining and cell survival assays indicated that BTC NPs could re-educate 87% of the M2-like RAW264.7 macrophages stimulated by apoptotic tumor cell secretion and significantly inhibit the liver tumor cell proliferation. Notably, in a mouse H22 liver cancer model, compared with mono PTT with BTiO2, the PTT treatment of BTC could reverse the ratio of M2 : M1 from 3.3 : 1 to 0.5 : 1, thus leading to 20.7% increase in the tumor inhibition rate. In general, our study demonstrated that zwitterionic COS can act as a potent immune activator to re-educate TAMs to M1. Furthermore, equipping the photothermal material with zwitterionic COS can be a potential treatment paradigm to achieve more forceful PTT.

Mesona chinensis Benth polysaccharides protect against oxidative stress and immunosuppression in cyclophosphamide-treated mice via MAPKs signal transduction pathways

In this study, the immune responses of Mesona chinensis Benth polysaccharides (MP) in vitro and in vivo were investigated. Results showed that MP presented immunomodulatory activities on macrophages and T lymphocytes in vitro. Compared with the cyclophosphamide (Cy)-induced immunosuppressive mice, the body weights, spleen indexes (3.45 to 4.91) and thymus indexes (0.78 to 1.04) of the mice treated with MP were increased, and the peripheral blood levels were recovered. MP treatment also increased superoxide dismutase, glutathione peroxidase and catalase activities, and reduced malondialdehyde levels to enhance the total antioxidant capacity of Cy-treated mice. In addition, MP significantly elevated IL-2, NO, and IFN-γ secretions of splenic lymphocytes and spleen, while MP mainly exerts an immune effect by regulating T lymphocytes. Furthermore, MP possessed the immunomodulatory activity by up-regulating the phosphorylation levels of proteins factors (c-Jun N-terminal kinase, extracellular regulated protein kinase and p38 kinase) in mitogen activated protein kinases signaling pathways. This study suggested that MP may be explored as a natural immune stimulant for functional food and nutraceutical industries.

Development of a Highly Efficient Hybrid Peptide That Increases Immunomodulatory Activity Via the TLR4-Mediated Nuclear Factor-κB Signaling Pathway

Immunity is a defensive response that fights disease by identifying and destroying harmful substances or microbiological toxins. Several factors, including work-related stress, pollution, and immunosuppressive agents, contribute to low immunity and poor health. Native peptides, a new class of immunoregulatory agents, have the potential for treating immunodeficiencies, malignancies, and infections. However, the potential cytotoxicity and low immunoregulatory activity and stability of native peptides have prevented their development. Therefore, we designed three hybrid peptides (LTA_a, LTA_b, and LTA_c) by combining a characteristic fragment of LL-37 with an active Tα1 center that included Tα1 (17-24), Tα1 (20-25), and Tα1 (20-27). The best hybrid peptide (LTA_a), according to molecule docking and in vitro experiments, had improved immunoregulatory activity and stability with minimal cytotoxicity. We investigated the immunoregulatory effects and mechanisms of LTA_a using a cyclophosphamide-immunosuppressed murine model. LTA_a effectively reversed immunosuppression by enhancing immune organ development, activating peritoneal macrophage phagocytosis, regulating T lymphocyte subsets, and increasing cytokine (tumor necrosis factor-alpha, interleukin-6, and interleukin-1β) and immunoglobulin (IgA, IgG, and IgM) contents. The immunomodulatory effects of LTA_a may be associated with binding to the TLR4/MD-2 complex and activation of the NF-κB signaling pathway. Therefore, LTA_a could be an effective therapeutic agent for improving immune function.

Purification, structural elucidation and in vivo immunity-enhancing activity of polysaccharides from quinoa (Chenopodium quinoa Willd.) seeds

Quinoa crude polysaccharides (QPS) were extracted from Chenopodium quinoa Willd. The soluble non-starch polysaccharide fraction (QPS1) was subsequently purified by DEAE-52 cellulose and Sephadex G-50 gel chromatography, using QPS as raw materials. Its chemical structure was identified using FT-IR, NMR, AFM, SEM and Congo red staining. High performance gel permeation chromatography (HPGPC) was used to determine molecular weight, and composition by HPLC. QPS1, with a molecular weight of 34.0 kDa, was mainly composed of mannose, rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose at a molar ratio of 2.63:2.40:1.64:6.28:1.95:2.48:5.01. In addition, we evaluated the ameliorative effects of QPS1 on the improvement of anti-cyclophosphamide (CTX)-induced immunosuppression in ICR mice. The result exhibited significantly immune-enhancing activity: QPS1 successfully improved the content of IFN-γ, IL-6, IFN-ɑ, IgM and lysozyme (LYSO) in serum for three weeks, enhanced the phagocytic function of mononuclear macrophages and ameliorated delayed allergy in mice.

In Vivo and In Vitro Study of Immunostimulation by Leuconostoc lactis-Produced Gluco-Oligosaccharides

Glycosyltransferase-producing Leuconostoc lactis CCK940 produces CCK- oligosaccharides, gluco-oligosaccharide molecules, using sucrose and maltose as donor and acceptor molecules, respectively. In this study, the immunostimulatory activities of CCK-oligosaccharides on RAW264.7 macrophages and BALB/c mice were evaluated. CCK-oligosaccharides induced the expression of phosphorylated-p38, extracellular-signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) and upregulation of phagocytic activity in RAW264.7 macrophages, suggesting their involvement in mitogen-activated protein kinase (MAPK) signaling pathway and phagocytosis. When CCK-oligosaccharides were administered to mice intraperitoneally injected with cyclophosphamide (CY), spleen indices and expressions of interleukin (IL)-6, IL–10, and tumor necrosis factor-α increased, compared with those in only CY-treated group. These findings suggest that CCK-oligosaccharides can be used as an effective immunostimulating agent.

A Novel Method to Increase Tumor Ablation Zones With RFA by Injecting the Cationic Polymer Solution to Tissues: In Vivo and Computational Studies

OBJECTIVE

This study aims to examine, for the first time, the introduction of cationic polymer solutions to improve radiofrequency ablation (RFA) in terms of a potentially enlarged ablation zone.

METHODS

By using in vivo and computational RFA studies, two cationic polymers, Chitooligosaccharides (COS) and carboxymethyl chitosan (CMC), diluted in deionized water, were injected into tissues separately surrounding the RF bipolar electrode prior to power application. A total of 9 rabbits were used to 1) measure the increase in electrical conductivity of tissues injected with the cationic polymer solutions, and 2) explore the enhancement of the ablation performance in RFA trials. A computer model of RFA comprising a model of the solution diffusion with an RF thermal ablation model was also built, validated by the in vivo experiment, to quantitatively study the effect of cationic polymer solutions on ablation performances.

RESULTS

Compared to the control group, the electrical conductivity of rabbit liver tissues was increased by 42.20% (0.282 ± 0.006 vs. 0.401 ± 0.048 S/m, P = 0.001) and 43.97% (0.282 ± 0.006 vs. 0.406 ± 0.042 S/m, P = 0.001) by injecting the COS and CMC solution at the concentration of 100 mg/mL into the tissues, denoted COS_DW100 and CMC_DW100, respectively. Consequently, the in vivo experiments show that the ablation zone was enlarged by 95% (47.6 ± 6.3 vs. 92.6 ± 11.5 mm², P < 0.001) and 87% (47.6± 6.3 vs. 88.8 ± 9.6 mm², P < 0.001) by COS_DW100 and CMC_DW100, respectively. The computer simulation shows that the ablation zone was enlarged by 71% (51.9 vs. 88.7 mm²) and 63% (51.9 vs. 84.7 mm²) by COS_DW100 and CMC_DW100, respectively.

CONCLUSION

The injection of the cationic solution can greatly improve the performance of RFA treatment in terms of enlarging the ablation zone, which is due to the increase in the electrical conductivity of liver tissues surrounding the RF electrode.

SIGNIFICANCE

This study contributes to the improvement of RFA in the treatment of large tumors.

Effects of different molar mass chitooligosaccharides on growth, antioxidant capacity, non-specific immune response, and resistance to Aeromonas hydrophila in GIFT tilapia Oreochromis niloticus

A feeding trial was conducted to evaluate the effects of different molar mass chitooligosaccharides (1000 Da, 3000 Da and 8000 Da) on growth, antioxidant capacity, non-specific immune response, and resistance to Aeromonas hydrophila in GIFT tilapia (Oreochromis niloticus). A total of 600 fish were divided into four treatments with five replicates of thirty fish per tank. The results showed that the supplementation of 1000 Da and 3000 Da COS significantly improved the growth performance and feed utilization in GIFT tilapia. The trend of decreasing total cholesterol, triglyceride, ALT, and ACP activity was observed in fish fed diet supplemented COS. The supplementation of 1000 Da and 3000 Da COS significantly improved the serum TAC activity, and decreased the serum MDA and catalase activities (P < 0.05). The lysozyme activity of blood, liver, and gills in fish fed diets supplemented with 1000 Da and 3000 Da COS was significantly higher than that of fish fed control diet after 56 days of feeding (P < 0.05). The phagocytic activity and phagocytic index of fish fed diets supplemented with 1000 Da and 3000 Da COS were significantly higher than those of fish fed control diet. Post-challenge test showed that fish mortality in 1000 Da, 3000 Da, and 8000 Da COS groups were significantly lower than that of fish in control group (P < 0.05). In conclusion, the present study indicated that dietary 1000 Da and 3000 Da COS supplementation could enhance more performance and immune response of GIFT tilapia than 8000 Da COS.

Immunomodulatory role of chitosan-based nanoparticles and oligosaccharides in cyclophosphamide-treated mice

Chitosan, the deacetylated form of chitin, a natural polysaccharide, is known for its various biomedical applications. The present study aimed at exploring the immunomodulatory properties of chitosan (CSNP) and gallic acid-grafted chitosan (cGANP) nanoparticles in mice model of cyclophosphamide (CPA)-induced immunosuppression. In addition, chitooligosaccharides, the hydrolysed form of chitin and chitosan, were also evaluated for its potential against immunosuppression in mice. CPA (80 mg/kg/ip) induced significant immunosuppression, which was reversed with cGANP treatment as indicated by a significant increase in the thymus and spleen indices compared to the CPA-treated group. The CSNP and chitooligosaccharides (chitin and chitosan) failed to reverse CPA-induced changes. ELISA revealed an elevation in the levels of IL-6 and a reduction in IFN-γ levels with CPA treatment. All the test compounds reduced the IL-6 levels, whereas only the nanoparticle formulations (CSNP and cGANP) exhibited a significant augmentation in the IFN-γ levels. Both the cytokines, IL-6 and IFN-γ, are secreted separately by two different types of T helper cells (Th cells), which mediate cellular and humoral immune responses in a coordinated manner. Th-1 cells release IFN-γ, facilitating cell-mediated immunity, whereas IL-6 is released by Th-2 cells, expediting humoral immune response. The nanoparticles (CSNP and cGANP) seemed to be better immune enhancers than the chitooligosaccharides owing to their ability to reverse the cytokine changes induced by CPA. Overall, it was evident that the nanoparticles, most likely, boosted the cell-mediated immunity through the induction of the Th-1 branch of the immune response.

Glycosaminoglycan from Apostichopus japonicus induces immunomodulatory activity in cyclophosphamide-treated mice and in macrophages

This study was designed to systematically elucidate the immunomodulation effect of glycosaminoglycan from Apostichopus japonicus (AHG) in cyclophosphamide (CY)-induced immunosuppression model and potential mechanism responsible for the activation of macrophages. The results showed that the treatment with AHG could increase natural killer (NK) cell cytotoxicity, carbon clearance and marker enzymes activities in CY-induced immunosuppression mice, indicating that the innate immunity experienced recovery to some extent. Moreover, CY-induced reductions in thymus and spleen indices, serum levels of cytokines, immunoglobulins and hemolysin, as well as the ratio of spleen lymphocyte subsets were recovered by AHG, suggesting that AHG could improve the adaptive immunity through cellular immunity and humoral immunity. Delightedly, it was found that AHG at 10 mg/kg body weight could restore the CY-induced immunosuppression in mice to normal level on both innate and adaptive immunity. Furthermore, AHG also promoted both the expression of NO, TNF-α, IL-6, IL-1β, IL-18 and MCP-1 protein and related mRNA in macrophages. It was revealed that AHG activated macrophages through the phosphorylation of mitogen-activated protein kinase (MAPK) and nuclear factor-B (NF-κB). In conclusion, AHG exerts remarkable immunomodulatory activities in both innate and adaptive immune system. These findings should have great value for further study on the immunopotentiating mechanisms of this biomacromolecule.

Cloning, expression and characterization of a novel chitosanase from Streptomyces albolongus ATCC 27414

A gene encoding chitosanase from Streptomyces albolongus was cloned, sequenced and expressed in Escherichia coli. The novel recombinant enzyme (Csn21c) was purified by Ni-NTA Superflow Column and showed a molecular mass of 29.6 kDa by SDS-PAGE. The enzyme Csn21c showed the optimal activity in 50 mmol/L Tris-HCl buffer, pH 8.0, and 50 °C and it was strongly activated (2-fold) by Mn²⁺. It belonged to glycoside hydrolase 46 family according to NCBI database (http://www.ncbi.nlm.nih.gov/) and displayed an exo-type cleavage pattern, hydrolyzing chitosan mainly into d-glucosamine (GlcN) and chitobiose ((GlcN)₂) as confirmed by TLC and MS analysis. This study demonstrated that Csn21c can be an effective tool to produce abundant glucosamine and chitooligosaccharides (COS) from chitosan.