Role of ADMA/DDAH-1 and iNOS/eNOS signaling in the gastroprotective effect of tadalafil against indomethacin-induced gastric injury

Pylorus ligation-induced hyperacidity: synergistic prophylactic effects of linagliptin and L-arginine via up-regulation of EP4 receptor subtype and improvement of vascular endothelial damage

Gastric hyperacidity and ulceration are chronic diseases characterized by repeated healing followed by re-exacerbation. The study aims to protect against gastric hyperacidity without interfering with gastric acid secretion. Pylorus ligation-induced hyperacidity is commonly utilized in the induction of gastric ulcers.Forty-two rats were distributed into seven groups (n = 6). Group I comprised sham-operated group. Group II served as pylorus-ligation group. Groups III-VII were given oral Linagliptin (LN; 3 and 6 mg/kg), L-arginine (LA; 150 and 300 mg/kg) and their combination (LN 3 + LA 150 mg/kg), respectively for 7 days. On the 8th day, groups II-VII were subjected to pylorus-ligation.Treatment of pylorus-ligated rats with LN, LA and their combination improved the gastric hyperacidity as exhibited by a marked reduction in the gastric juice volume, total and free acidities and pepsin contents with a noticeable increase in pH. Pre-treatment with LN, LA and their combination showed a marked alleviation in the gastric inflammatory indicators evidenced by reduction in the gastric levels of MCP-1and Il-1β as well as elevation of eNOS levels versus the sham-operated group. A marked up-regulation in the gastric gene expression of PGE, EP4 and VEGF accompanied by an improvement of the histopathologic pictures/scores, and TNF-α and caspase-3 immuno-staining were also recorded.By estimating the combination-index, it can be concluded that combining LN with LA exhibited prophylactic synergistic effects in ameliorating pylorus ligated-induced hyperacidity, mainly via up-regulation of EP4 receptor and improvement of vascular endothelial damage through VEGF expression in gastric mucosa.

α-Mangostin suppresses ethanol-induced gastric ulceration by regulating the Nrf2/HO-1 and NF-κB/NLRP3/caspase-1 signaling pathways and gut microbiota

α-Mangostin is a natural xanthone derivative isolated from Camellia atrophy (CA), commonly known as Lichuan black tea (LBT). The present study investigated the ameliorating effect and mechanism of α-mangostin on alcoholic gastric ulcers (GU) in rats. In vivo, α-mangostin relieved pathological symptoms. Moreover, α-mangostin regulated the activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase 1 (HO-1) and nuclear factor κB (NF-κB)/NLR family pyrin domain containing 3 (NLRP3)/caspase-1 pathways. Reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were significantly decreased and IL-10 were increased, the microtubule-associated protein light chain 3 (LC3)-II/LC3-I ratio was increased, p62 protein expression was decreased, and inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) protein expression was down-regulated. The relevant mechanisms were validated using GSE-1 and RAW264.7 cells in an in vitro model. Furthermore, α-mangostin increased Ligilactobacillus and Muribaculum abundance as well as propionic acid and butyric acid contents. Therefore, α-mangostin possesses antioxidant and anti-inflammatory properties, and remodels intestinal flora dysbiosis through mechanisms that may involve regulation of the Nrf2/HO-1 pathway and NF-κB/NLRP3/caspase-1 pathway. It also increases propionic acid and butyric acid contents. This study provides novel evidence regarding the use of α-mangostin for treating GU.

Effects of Huzhangoside C on Dextran Sodium Sulfate-Stimulated Colitis in Mice

Chronic inflammation is a major risk factor for cancer. Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, ultimately leading to a breakdown of intestinal barrier function. Clematis florida var. plena is a folk prescription used to treat inflammation and rheumatism in She pharmacy. The bioactivity of C. florida var. plena is primarily due to triterpene saponins. Huzhangoside C (HZ) is an active component of C. florida var. plena. In this study, the anti-inflammatory effect of HZ on a mouse colitis model induced by dextran sulfate sodium (DSS) was investigated. Result indicated a notable reduction in body weight loss and colon length shortening in HZ-mediated mice compared to DSS-stimulated control mice. Furthermore, inflammatory signaling mechanisms involving interleukin-6 and tumor necrosis factor-α were suppressed in HZ-treated mice. HZ treatment significantly suppressed the expression of nuclear factor kappa B (NF-κB), STAT3, and iNOS in colon tissue. After HZ treatment, malondialdehyde and nitric oxide levels were significantly decreased, while Nrf-2, superoxide dismutase, and glutathione expression levels were notably improved. The result indicated that HZ could activate the Nrf-2 signal cascade, inhibit the expression of NF-κB, eNOS, and STAT3, and enhance the intestinal barrier function of DSS stimulated ulcerative colitis intestinal injury. The results suggest that HZ is potential anti-inflammatory agent for treating IBD.

All That Glitters Is Not Gold: Assessment of Bee Pollen Supplementation Effects on Gastric Mucosa

The aim of this study was to assess the influence of bee pollen supplementation on the levels of enzymes important for gastric mucosal homeostasis, namely cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and a biomarker-asymmetric dimethylarginine (ADMA)-in the gastric mucosa of Wistar rats. The experimental phase divided the rats into four groups: two control groups, sedentary and active, both not supplemented, and two experimental groups, sedentary and active, supplemented with bee pollen. The results indicated that bee pollen supplementation reduced the levels of COX-1 and elevated iNOS levels, while showing no significant impact on COX-2 levels. These findings do not conclusively support the gastroprotective and anti-inflammatory effects of bee pollen on gastric mucosa. However, the supplementation could have resulted in reduced ADMA levels in the physically active supplemented group. Our study does not unequivocally demonstrate the positive effects of bee pollen supplementation on the gastric mucosa, which may be attributed to the specific metabolism and bioavailability of substances within unprocessed, dried bee pollen. Further research should explore the topic of potential therapeutic applications of bee pollen in gastrointestinal health and its interactions with ADMA signaling pathways.

PDE5 inhibitors and gastric mucosa: implications for the management of peptic ulcer disease

Peptic ulcer disease (PUD) continues to be a cause of significant morbidity and mortality worldwide. Almost two-thirds of PUD cases are asymptomatic. In symptomatic patients, epigastric pain is the most common presenting symptom of PUD, which is manifested by nausea, abdominal fullness, bloating, and dyspepsia. Most PUD cases are associated with the use of COX inhibitors or Helicobacter pylori infection, or both. The traditional management of PUD includes the use of proton pump inhibitors to reduce the gastric acid secretion and antibacterial drugs to combat H. pylori. Timely diagnosis and treatment of PUD are vital to reduce the risk of associated morbidity and mortality, as is prevention of PUD among patients at high risk, including COX inhibitors users and those infected with H. pylori. PDE5 inhibitors have been used for the management of erectile dysfunction and pulmonary hypertension for decades. In recent years, studies have mentioned tremendous pleiotropic effects of PDE5 inhibitors on gastrointestinal, urogenital, musculoskeletal, reproductive, cutaneous, and neurologic disorders. Recent data shows that PDE5 inhibition augments gastric mucosa protection, and here, we review the most recent findings regarding the use of PDE5 inhibitors for the prevention and management of PUD.

Gastroprotective mechanism of modified lvdou gancao decoction on ethanol-induced gastric lesions in mice: Involvement of Nrf-2/HO-1/NF-κB signaling pathway

Modified Lvdou Gancao decoction (MLG), a traditional Chinese medicine formula, has been put into clinical use to treat the diseases of the digestive system for a long run, showing great faculty in gastric protection and anti-inflammatory, whereas its protective mechanisms have not been determined. The current study puts the focus on the protective effect and its possible mechanisms of MLG on ethanol-induced gastric lesions in mice. In addition to various gastric lesion parameters and histopathology analysis, the activities of a list of relevant indicators in gastric mucosa were explored including ALDH, ADH, MDA, T-SOD, GSH-Px, and MPO, and the mechanisms were clarified using RT-qPCR, ELISA Western Blot and immunofluorescence staining. The results showed that MLG treatment induced significant increment of ADH, ALDH, T-SOD, GSH-Px, NO, PGE2 and SS activities in gastric tissues, while MPO, MDA, TNF-α and IL-1β levels were on the decline, both in a dose-dependent manner. In contrast to the model group, the mRNA expression of Nrf-2 and HO-1 in the MLG treated groups showed an upward trend while the NF-κB, TNFα, IL-1β and COX2 in the MLG treated groups had a downward trend simultaneously. Furthermore, the protein levels of p65, p-p65, IκBα, p-IκBα, iNOS, COX2 and p38 were inhibited, while Nrf2, HO-1, SOD1, SOD2 and eNOS were ramped up in MLG treatment groups. Immunofluorescence intensities of Nrf2 and HO-1 in the MLG treated groups were considerably enhanced, with p65 and IκBα diminished simultaneously, exhibiting similar trends to that of qPCR and western blot. To sum up, MLG could significantly ameliorate ethanol-induced gastric mucosal lesions in mice, which might be put down to the activation of alcohol metabolizing enzymes, attenuation of the oxidative damage and inflammatory response to maintain the gastric mucosa. The gastroprotective effect of MLG might be achieved through the diminution of damage factors and the enhancement of defensive factors involving NF-κB/Nrf2/HO-1 signaling pathway. We further confirmed that MLG has strong potential in preventing and treating ethanol-induced gastric lesions.