Structural studies of water-soluble polysaccharides of an edible mushroom, Termitomyces eurhizus. A reinvestigation

The structure of two polysaccharides isolated from the hot aqueous extract of fruiting bodies of the mushroom, Termitomyces eurhizus, have been reinvestigated. These consist of two homogeneous fractions PS-I and PS-II. PS-I contains only D-glucose as the monosaccharide constituent. From methylation analysis and periodate oxidation studies, followed by GLC-MS analysis the linkages, the sugar units in PS-I were identified as (1-->3)-D-Glcp and (1-->6)-D-Glcp. PS-II contains D-glucose, and the mode of linkage of d-glucose was identified as (1-->6)-D-Glcp. Finally, the following possible structures of the polysaccharides were assigned using 1H, 2D-COSY, TOCSY, NOESY and 13C NMR spectral analysis: [carbohydrate structure: see text].     

Role of nuclear factor-kappaB in gastric ulcer healing in rats

We investigated the role of nuclear factor-kappaB (NF-kappaB) in gastric ulcer healing in rats. NF-kappaB was activated in ulcerated tissue but not in normal mucosa, and the level of the activation was decreased with ulcer healing. NF-kappaB activation was observed in fibroblasts, monocytes/macrophages, and neutrophils. Treatment of gastric fibroblasts, isolated from the ulcer base, with interleukin-1beta activated NF-kappaB and the subsequently induced cyclooxygenase-2 and cytokine-induced neutrophil chemoattractant-1 (CINC-1) mRNA expression. Inhibition of activated NF-kappaB action resulted in suppression of both their mRNA expression and increases in PGE(2) and CINC-1 levels induced by interleukin-1beta. Persistent prevention of NF-kappaB activation caused an impairment of ulcer healing in rats. Gene expression of interleukin-1beta, CINC-1, cyclooxygenase-2, and inducible nitric oxide synthase in ulcerated tissue had been inhibited before the delay in ulcer healing became manifest. The increased levels of cyclooxygenase-2 protein and PGE(2) production were also reduced. These results demonstrate that NF-kappaB, activated in ulcerated tissue, might upregulate the expression of healing-promoting factors responsible for gastric ulcer healing in rats.     

Pulicaria crispa mitigates gastric ulcer induced by ethanol in rats: role of treatment and auto healing

Context: Stomach ulcers are the common gastrointestinal disorders worldwide.

Objective: This study aimed to investigate the therapeutic impact of Pulicaria crispa aerial parts ethanol extract against gastric ulcer in rats.

Materials and methods: Ulcer was induced by one oral dose of ethanol (0.5?ml/100g body weight) on 24?hours empty stomach, then the plant extract (500?mg/kg b.wt.) was orally administered daily for one week. Ranitidine (100?mg/kg b.wt.); as a reference drug was evaluated. Stomach acidity and volume, as well as lesion counts were measured. Levels of malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) were estimated. Assay of different marker enzymes; succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), glucose-6-phosphatase (G-6-Pase), acid phosphatase (AP) and 5′-nucleotidase (5′NT) were determined. Interlukin-10 (IL-10), intracellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor alpha (TNF-α) were also determined. Stomach histopathological assessment was detected.

Results: Gastric ulcer showed drastic changes in oxidative stress, cell organelles and inflammatory markers. These biomarkers served as good tools to identify the presence of gastric ulcer. Treatment with P. crispa recorded amelioration in most parameters exceeding the auto healing effect.

Conclusion: Healing potency of P. crispa is possibly related to its content of glycosides, coumarins, flavonoids, tannins, sterols and triterpenes.     

Endothelial nitric oxide synthase modulates gastric ulcer healing in rats

Nitric oxide has been shown to be beneficial for gastric ulcer healing. We determined the relative effects of endothelial and inducible nitric oxide synthases on gastric ulcer healing in rats. Ulcers were induced by serosal application of acetic acid. Ulcer severity, angiogenesis, and nitric oxide synthase expression were assessed 3-10 days later. The effects of inhibitors of nitric oxide synthase were also examined. Inducible nitric oxide synthase mRNA was only detected in ulcerated tissue (maximal at day 3), whereas the endothelial isoform mRNA was detected in normal tissue and increased during ulcer healing. Inducible nitric oxide synthase was expressed in inflammatory cells in the ulcer bed, whereas endothelial nitric oxide synthase was found in the vascular endothelium and in some mucosal cells in both normal and ulcerated tissues. Angiogenesis changed in parallel with endothelial nitric oxide synthase expression. N(6)-(iminoethyl)-L-lysine did not affect angiogenesis or ulcer healing, while N(G)-nitro-L-arginine methyl ester significantly reduced both. In conclusion, endothelial nitric oxide synthase, but not the inducible isoform, plays a significant role in gastric ulcer healing.     

Effect of polysaccharides from Angelica sinensis on gastric ulcer healing

Our previous study showed that a crude extract from Angelica sinensis (ASCE), which mainly consisted of polysaccharides, significantly promoted migration and proliferation of normal gastric epithelial cells. These results strongly suggest that ASCE has a direct wound healing effect on gastric mucosa. However, there is no report concerning the effect of ASCE on gastric ulcer healing in animal models. In this study, we found that ASCE promoted ulcer healing. The area of the ulcer was reduced. This was accompanied with a significant increase in mucus synthesis when compared with the control. Angiogenesis was inhibited by the treatment of ASCE. Cell proliferation, ODC and EGFR protein expression was not affected in this process. Thus, the mechanism of how ASCE accelerates ulcer healing in addition to its effect on mucus synthesis remains to be investigated.     

A water-insoluble (1-->3)-beta-D-glucan from the alkaline extract of an edible mushroom Termitomyces eurhizus

A water-insoluble glucan, TEINS has been isolated from the hot alkaline extract of an edible mushroom Termitomyces eurhizus. The total carbohydrate content of the polysaccharide fraction was found to be 98.4%, and it was found to contain only glucose as the monosaccharide constituent. On the basis of total acid hydrolysis, a methylation experiment, periodate oxidation and (13)C NMR experiment, the repeating unit of the polysaccharide was established as: -->3)-beta-D-Glcp-(1-->.     

Polysaccharide-rich fraction of Agaricus brasiliensis enhances the candidacidal activity of murine macrophages

A polysaccharide-rich fraction (ATF) of medicinal mushroom Agaricus brasiliensis was evaluated on the candidacidal activity, H2O2 and nitric oxide (NO) production, and expression of mannose receptors by murine peritoneal macrophages. Mice received three intraperitoneal (i.p.) injections of ATF and after 48 h their peritoneal resident macrophages were assayed against Candida albicans yeast forms. The treatment increased fungicidal activity and it was associated with higher levels of H2O2, whereas NO production was not affected. We also found that the treatment enhances mannose receptor expression by peritoneal macrophages, which are involved in the attachment and phagocytosis of non-opsonized microorganisms. Treatment of animals with ATF was able to enhance the clearance of C. albicans during the first 6 h after the experimental i.p. infection. Our results suggest that this extract can increase host resistance against some infectious agents through the stimulation of microbicidal activity of macrophages.     

木瓜三萜对吲哚美辛致胃黏膜损伤小鼠胃酸分泌及胃黏膜屏障的影响

观察木瓜三萜对吲哚美辛致胃黏膜损伤小鼠胃酸分泌及胃黏膜屏障的影响,在此基础上探讨其可能的机制。实验时,将小鼠随机分为正常组、模型组、木瓜三萜(50、100mg/kg)和奥美拉唑(20mg/kg)组。将给药组灌胃给予相应的药物,正常组和模型组灌胃给予0.5%羧甲基纤维素钠溶液,给药6小时后,除正常组外,灌胃给予20mg/kg的吲哚美辛,每天一次,连续7天。末次给药次日,小鼠用水合氯醛麻醉后,固定,剪开腹腔,进行胃黏膜血流量的测定,然后取胃检测胃液量、胃液酸度和胃结合黏液量;检测胃黏膜中表皮生长因子基因(EGF)和三叶因子1基因(TFF1)的mRNA和蛋白表达。研究发现:吲哚美辛致胃黏膜损伤模型组小鼠胃液分泌量,胃液酸度、胃黏膜血流量、胃结合黏液量及胃黏膜组织中EGF和TFF1的mRNA和蛋白表达明显降低,与正常组比较均具有统计学差异(P<0.01);用木瓜三萜预处理后,上述异常的变化均得到了有效逆转,与模型组比较具有显著性差异(P<0.05,P<0.01)。实验结果表明木瓜三萜(50、100mg/kg)对吲哚美辛致小鼠胃黏膜损伤具有较好的保护作用,通过上调EGF和TFF1的表达水平,增加胃液分泌量、胃液酸度、胃黏膜血流量、胃结合黏液量,恢复胃黏膜防御屏障的功能可能是其治疗吲哚美辛致胃黏膜损伤的机制之一。     

Ellagic acid facilitates indomethacin-induced gastric ulcer healing via COX-2 up-regulation

The mechanism of indomethacin-induced gastric ulcer healing by ellagic acid (EA) in experimental mice model is described in our study. Ulcer index (UI) and myeloperoxidase (MPO) activity of the stomach tissues showed maximum ulceration on the third day after indomethacin (18 mg/kg, single dose) administration. Preliminary observation of UI and MPO activity suggests that EA possesses ulcer-healing activity. Other anti-ulcer parameters such as the levels of prostaglandin E(2), cyclooxygenase (COX) 1 and 2 enzymes, anti-inflammatory cytokines [interleukin (IL)-4 and -5], pro-angiogenic factors, e.g. vascular endothelial growth factor, hepatocyte growth factor (HGF), and endothelial growth factor (EGF) were down-regulated by indomethacin. EA (7 mg/kg/day) treatment for 3 days shifted the indomethacin-induced pro-inflammatory biochemical parameters to the healing side. These activities were correlated with the ability of EA to alter the COX-2-dependent healing pathways. The ulcer-healing activity of EA was, however, compromised by pre-administration of the specific COX-2 inhibitor, celecoxib, and NS-398. Taken together, these results suggested that the EA treatment accelerates ulcer healing by inducing IL-4, EGF/HGF levels and enhances COX-2 expression.     

Downregulation of endothelin-1 by interleukin-4 during gastric ulcer healing.

We investigated the course of events associated with gastric ulcer healing by analyzing mucosal expression of interleukin-4 (IL-4), endothelin-1 (ET-1), tumor necrosis factor-alpha (TNF-alpha), and the activity of constitutive (cNOS) and inducible nitric oxide synthase (NOS-2). Ulcer onset was characterized by a massive epithelial apoptosis associated with a 5.7-fold increase in TNF-alpha, a 17.5-fold increase in NOS-2, and a 3.9-fold increase in ET-1, while mucosal expression of cNOS showed a 7.6-fold drop and IL-4 fell by 37.2%. Healing was accompanied by a rapid raise in IL-4; decrease in apoptosis, TNF-alpha, ET-1, and NOS-2; and a slow recovery in cNOS. The expression of IL-4 returned to control levels by the 7th day of healing and that of ET-1 and TNF-alpha by the 14th day, while apoptotic DNA fragmentation and the activity of NOS-2 remained significantly elevated beyond the 14-day period. The results suggest that a decrease in the mucosal level of IL-4 at ulcer onset may well be a key factor causing dysregulation of ET-1 production, induction of TNF-alpha, and triggering the apoptotic events that affect the efficiency of mucosal repair.     

Endothelin-1, an ulcer inducer, promotes gastric ulcer healing via mobilizing gastric myofibroblasts and stimulates production of stroma-derived factors

Endothelin (ET)-1 is a potent inducer of peptic ulcers. The roles of ET-1 in ulcer healing, however, have remained unclear, and these were investigated in mice. Gastric ulcers were induced in mice by serosal application of acetic acid. Three days later, mice were given a neutralizing ET-1 antibody or nonimmunized serum. The ulcer size, amount of fibrosis and myofibroblasts, and localization of ET-1 and ET(A/B) receptors were analyzed. To elucidate the mechanisms underlying the effects of ET-1, we examined the proliferation, migration, and release of growth and angiogenic factors in gastric myofibroblasts with or without ET-1. The expression of prepro-ET-1 (an ET-1 precursor) and ET-converting enzyme-1 was examined in gastric myofibroblasts using RT-PCR. Immunoneutralization of ET-1 delayed gastric ulcer healing. The areas of fibrosis and myofibroblasts were smaller in the anti-ET-1 antibody group than in the control. ET-1 was expressed in the gastric epithelium, myofibroblasts, and other cell types. ET(A) receptors, but not ET(B) receptors, were present in myofibroblasts. ET-1 increased proliferation and migration of gastric myofibroblasts. ET-1 stimulated the release of hepatocyte growth factor, VEGF, PGE(2), and IL-6 from gastric myofibroblasts. mRNA for prepro-ET-1 and ET-converting enzyme-1 was also expressed. ET-1 promotes the accumulation of gastric myofibroblasts and collagen fibrils at gastric ulcers. ET-1 also stimulates migration and proliferation of gastric myofibroblasts and enhances the release of growth factors, angiogenic factors, and PGE(2). Thus ET-1 has important roles not only in ulcer formation but also in ulcer healing via mobilizing myofibroblasts and inducing production of stroma-derived factors.     

A new ulcer model, "unhealed gastric ulcers", induced by chronic treatment with indomethacin in rats with acetic acid ulcers.

The healing of experimental gastric ulcers induced in rats is consistently delayed upon chronic treatment with indomethacin. This study was designed to examine both the fate of such delayed ulcers and the effects of various antiulcer drugs on the delayed ulcers. Four-week treatment with indomethacin significantly delayed the healing of acetic acid ulcers. Such ulcers remained unhealed for up to 12 weeks after cessation of indomethacin treatment, and were thus designated as "unhealed ulcers". Two-week administration of sucralfate, cimetidine or omeprazole significantly reduced the ulcerated area, yet aluminum hydroxide had little or no effect. Four-week administration of sucralfate also extensively reduced the size of the "unhealed ulcers", yet aluminum hydroxide, cimetidine and omeprazole had an insignificant effect on "unhealed ulcers". In the 2 and 4 week sucralfate-treated group, the pH of the gastric contents was 4.0 vs. 1.7 and 4.5 vs. 2.1 in the control groups, respectively. Gastric acid secretion was extensively inhibited by cimetidine and omeprazole. It is concluded that prolonged indomethacin treatment results in the development of "unhealed ulcers" and that only sucralfate has a beneficial effect on such ulcers, irrespective of the length of the treatment.     

Role of capsaicin sensory nerves and EGF in the healing of gastric ulcer in rats

Accumulating evidence indicates that capsaicin sensitive afferent fibers play a pivotal role not only in gastroprotection but also in ulcer healing. Denervation of capsaicin sensitive afferent fibers exerts an adverse action on these effects. However, whether such an action is mediated through a depression on epidermal growth factor (EGF) is undefined. In this study, the effects of denervation of sensory neurons with capsaicin (100 mg/kg, s.c.) on acetic acid-induced chronic gastric ulcers and their relationship with the EGF expression in salivary glands, serum and gastric mucosa were investigated. Capsaicin significantly increased ulcer size, decreased gastric mucosal cell proliferation at the ulcer margin, angiogenesis in the granulation tissue and also gastric mucus content. Ulcer induction by itself dramatically elevated EGF levels in salivary glands and serum on day 1 and 4, and also in the gastric mucosa on day 4. However, capsaicin completely abolished these effects. It is concluded that stimulation of EGF expression in salivary glands and serum may be one of the mechanisms by which capsaicin sensitive nerves contribute to the gastroprotective and ulcer healing actions in the stomach.     

Serum-derived exosomes accelerate scald wound healing in mice by optimizing cellular functions and promoting Akt phosphorylation

Wound exudate holds great clinical and research potential in wound repair via paracrine signaling. In essence, exudate is modified serum that contains a high concentration of exosomes. The aim of this study was to investigate the role of serum-derived exosomes in scald wound healing of NIH mice skin and to explore the underlying mechanisms. Hence, we constructed a deep second-degree scald model in NIH mice, testing the benefits of exosomes in the scald wound healing. The scratch wound assay, apoptosis assay and MTT assay were conducted to assess the effects of serum-derived exosomes on migration, apoptosis and proliferation of HaCaT cells and fibroblasts. Our results showed that serum-derived exosomes injected subcutaneously entered cells and effectively accelerated wound healing processes in mice. Additionally, serum-derived exosomes optimized functions of cells related to skin injury repair by stimulating fibroblast proliferation, promoting HaCaT cell migration, and suppressing apoptosis of HaCaT cells induced by heat stress. Further study revealed that serum-derived exosomes enhanced phosphorylation of the serine-threonine kinase Akt in scalded skin tissue. These results suggest a potential clinical use of serum-derived exosomes for treating skin scald.