Different protective capability of chlorogenic acid and quercetin against indomethacin-induced gastrointestinal ulceration

Quercetin inhibits calcium oxalate crystallization and growth but promotes crystal aggregation and invasion

Recent evidence has shown an association between kidney stone pathogenesis and oxidative stress. Many anti-oxidants have been studied with an aim for stone prevention. Quercetin, a natural flavonol, is one among those eminent anti-oxidants with satisfactory anti-inflammatory property to cope with renal tissue injury in kidney stone disease. Nevertheless, its direct effect (if any) on calcium oxalate (CaOx) crystals and the stone formation mechanism had not been previously explored. This study has addressed the ability of quercetin at various concentrations (2.5, 5, 10, 20, 40, 80 and 160 μM) to directly modulate CaOx crystallization, growth, aggregation, adhesion on kidney cells, and invasion through the matrix. The data have shown that quercetin significantly inhibits CaOx crystallization and crystal growth but promotes crystal aggregation in concentration-dependent manner. However, quercetin at all these concentrations do not affect CaOx adhesion on kidney cells. For the invasion, quercetin at all concentrations constantly promotes CaOx invasion through the matrix without concentration-dependent pattern. These discoveries have demonstrated for the first time that quercetin has direct but dual modulatory effects on CaOx crystals. While quercetin inhibits CaOx crystallization and growth, on the other hand, it promotes CaOx crystal aggregation and invasion through the matrix. These data highlight the role for quercetin in direct modulation of the CaOx crystals that may intervene the stone pathogenesis.

An integrated network analysis, RNA-seq and in vivo validation approaches to explore the protective mechanism of Mongolian medicine formulae Ruda-6 against indomethacin-induced gastric ulcer in rats

Gastric ulcer (GU) is one of the most prevalent digestive diseases that seriously affects people's health. Previous studies have demonstrated the anti-GU effect of Ruda-6 (RD-6), a classic formulae of traditional Mongolian medicine. However, the underlying mechanism of RD-6 against GU remains elusive. Thus, we conducted an integrative approach of network analysis, RNA-seq, and in vivo validation experiment to elucidate the therapeutic mechanisms of RD-6 in preventing GU. A network analysis was performed to predict the potential targets of RD-6. Rats were pretreated with RD-6 at different doses for 21 days, followed by GU induction with indomethacin injection. The ulcer index and inhibition rates were calculated, and the levels of inflammatory related factors were determined by ELISA. The gastroprotective mechanism of RD-6 against ulceration was verified by RNA-seq and the key pathway was detected by in vivo validation. As the network analysis predicted, RD-6 exerts anti-GU effects by regulating 75 targets and 160 signaling pathways. Animal experiment results suggested that pretreatment with RD-6 significantly ameliorated the gastric mucosal injury and inflammatory response, as evidenced by a reduced ulcer index, decreased interleukin (IL)-1β, IL-6, and IL-17 levels, and increased prostaglandin E2 (PGE2) levels in the GU model rats induced by indomethacin. RNA-seq data identified four potential hub genes that were primarily involved in the IL-17 signaling pathway. Furthermore, in vivo validation experiment showed that RD-6 inhibited the IL-17 signaling pathway by down-regulating the expression of IL17RA, proto-oncogene C-Fos (FOS), IL1B and prostaglandin-endoperoxide synthase 2 (PTGS2). Taken together, the present study provides evidence that RD-6 could effectively protect against indomethacin-induced GU, which might be attributed to suppressed inflammation. The IL-17 signaling pathway may be one of the crucial mechanisms that mediates the effect of RD-6.

Apple (Malus domestica Borkh) leaves attenuate indomethacin-induced gastric ulcer in rats

Malus domestica Borkh, the apple tree, exhibited numerous pharmacological properties including antioxidant, neuroprotective, anti-inflammatory, anticancer and antimicrobial activities. The present work aimed to annotate the secondary metabolites from a butanol fraction of apple leaves (BLE), evaluate the gastro-protective and healing effects of this fraction against indomethacin-induced gastric ulcers in rats and to identify its mechanism of action. BLE (100, and 200 mg/kg) was orally administered in rats as an acute treatment against indomethacin-induced gastric ulcer in comparison with famotidine as reference anti-ulcer drug. The stomachs of rats were collected to determine the ulcer index, the preventive ratio, measure the activity of glutathione peroxidase (GPx), and estimate the expression of cyclooxygenase-2 (COX-2), and heat shock protein 70 (HSP70). Furthermore, we evaluated both inflammatory and oxidative stress markers in the gastric tissues. We also performed histopathological study of gastric mucosa using H&E stain and periodic Schiff base stain to evaluate both gastric injury scores and gastric mucus content respectively. Pretreatment with BLE markedly lowered the severity of gastric injury induced by indomethacin, decreased oxidative stress, inflammatory cytokines, and COX-2 expression in the examined gastric tissues. The gastric healing effect of BLE was associated with increased mucoglycoproteins, and HSP70 expression. Additionally, gastric healing effect of high dose of BLE was superior to that of famotidine in decreasing gastric injury scores, COX-2, inflammatory cytokines, lipid peroxidation and in increasing gastric mucin content, HSP70, and reduced glutathione. These findings indicate that BLE is effective in accelerating ulcer healing by boosting HSP70 expression, and decreasing COX-2 expression, oxidative stress, and gastric inflammation which might be related to the presence of 21 phytoconstituents.