The effect of 1,25 dihydroxyvitamin D3 on HCl/Ethanol-induced gastric injury in rats

Histopathological role of vitamin D deficiency in recurrent/chronic tonsillitis pathogenesis: Vascular epithelial growth factor-mediated angiogenesis in tonsil

Objectives

Our aim in this study is to reveal the role of vitamin D deficiency in the pathogenesis of recurrent/chronic tonsillitis and to determine the expression of vascular epithelial growth factor (VEGF).

Material and Methods

This study was conducted between September and February. Thirty‐two patients between the ages of 3 and 35 (mean age 9.71) with recurrent episodes of chronic tonsillitis were selected. Patients were divided into four groups according to their 25OHD levels. Patients with 25OHD levels 0–10 ng/ml were determined as Group 1, 11–20 ng/ml Group 2, 21–30 ng/ml Group 3, and 31–50 ng/ml control Group 4. Routine histological tissue sampling was performed for histopathological evaluation of the tonsillar tissues under light microscope (LM). Five micron sections were taken from the paraffin blocks and stained with Hematoxylin Eosin (HE) and Trichrome Masson (TCM). VEGF expression was examined immunohistochemically for each group.

Results

Our analysis showed VEGF expression in all study groups (32 tonsillar tissues). Group 1 and Group 2 histopathological scores were significantly higher than the other groups (p < .001). There were significant differences in VEGF expressions between the four groups (p < .001). 25OHD levels of the patients in Groups 1 and 2 with strong VEGF expression were significantly lower than the other groups (p < .001).

Conclusions

In conclusion, this study showed an increased angiogenesis in tonsil and an increase in VEGF expression of the tonsillar surface epithelium when blood serum 25OHD levels <20 ng/ml.

Gastroprotective Activity of Neoglaziovia variegata (Arruda) Mez. (Bromeliaceae) in Rats and Mice

Neoglaziovia variegata (Arruda) Mez (Bromeliaceae) is a medicinal plant popularly known as "caroá." The leaves are made up of highly resistant fibers, which is of great commercial value to the handicraft and textile industry. Some studies have demonstrated that ethanolic extract of N. variegata have gastroprotective properties. This study aimed to investigate the gastroprotective activity and cytoprotective mechanisms of ethyl acetate (Nv-AcOEt), hexane (Nv-Hex), and chloroform (Nv-CHCl₃) fractions of N. variegata leaves. The gastroprotective activity of Nv-AcOEt, Nv-Hex, and Nv-CHCl₃ was evaluated using the ethanol and ethanol/HCl-induced gastric injury model. To elucidate the gastroprotective mechanisms, the functions of prostaglandins (PGs), nitric oxide (NO), and K_ATP channels were evaluated. In addition, the nonprotein sulfhydryl groups and the mucus content in the gastric tissues were analyzed. All fractions of N. variegata leaves at oral doses of 100, 200, and 400 mg/kg significantly decreased ethanol and ethanol/HCl-induced gastric lesions, leading to gastroprotection, accompanied by an increase in reduced glutathione (GSH) and gastric mucus. Gastroprotective activity of Nv-AcOEt was inhibited after pretreatment with ibuprofen and N(G)-nitro-L-arginine (L-NOARG). Gastroprotective effect of Nv-Hex and Nv-CHCl₃ was also inhibited after pretreatment with L-NOARG and with glibenclamide. The results indicate that N. variegata (Arruda) Mez exhibits promising gastroprotective activity with the possible participation of NO, PGs, mucus, sulfhydryl groups, and K_ATP.

Effect of fulvic acid on gastric mucosa damage caused by chronic water avoidance stress

We investigated the antioxidant and anti-ulcerogenic effects of fulvic acid (FA) on oxidative damage caused by water avoidance stress (WAS) in rat gastrointestinal mucosa. Three experimental groups were established: control (C), chronic stress (CS), and chronic stress + FA (CS + FA). After WAS, a single dose of FA was administered for 10 days to the CS + FA group. Samples of the pyloric region of the stomach were stained with hematoxylin and eosin (H & E) and periodic acid-Schiff (PAS). Immunohistochemical staining was performed for inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS). Total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) levels were measured biochemically. By light microscopy, we observed loss of gastric epithelial cells and greater polymorphonuclear cell migration into the mucosa in the CS group compared to the C group. We found intact epithelial cell structure and a thick superficial mucus layer in the CS + FA group compared to the CS group. These findings in the CS + FA group were similar to those for group C. iNOS staining was stronger in the CS group compared to the C group. TOS and OSI levels in the CS + FA group were decreased compared to the CS group, but TAS, SOD, GPx and CAT levels were increased. We found that WAS caused damage to epithelium and connective tissue of the stomach mucosa and that this damage was prevented by FA. Therefore, administration of FA appears to prevent stress induced damage to rat stomach.

Calcitriol inhibits apoptosis via activation of autophagy in hyperosmotic stress stimulated corneal epithelial cells in vivo and in vitro

BACKGROUND

Previously, calcitriol has been demonstrated as a potential therapeutic agent for dry eye, whilst its role on corneal epithelium death remains unclear. This study aims to investigate the relationship between apoptosis and autophagy on dry eye related scenario, as well as the effect of calcitriol and its potential mechanism.

METHODS

In vitro, immortalized human corneal epithelial cells (iHCEC) were cultured in hyperosmotic medium with or without various concentrations of calcitriol and other reagents. In vivo, Wistar rats were applied with benzalkonium chloride to induce dry eye. Then rats were topically treated with calcitriol (10^-6 M) for 14 days. Autophagy flux (LC3B-II and SQSTM1/P62) was examined by western blotting or immunostaining. To test cell apoptosis, western blotting for cleaved caspase-3, Annexin V/PI double staining and TUNEL assay were used. CCK-8 assay was performed to detect the cell viability. Small interfering RNA was used to knock down the expression of vitamin D receptor in iHCECs.

RESULTS

Autophagy activation could protect iHCECs against HS induced apoptosis in vitro, and calcitriol was able to augment autophagy flux via VDR signaling, shown as the remarkably elevated expression of LC3B-II, as well as the declined p62 expression. In vivo results further supported the protective role of calcitriol on corneal epithelium apoptosis through promoting autophagy in dry eye rats.

CONCLUSION

The current study indicated that autophagy was an adaptive change of corneal epithelial cells in response to hyperosmotic stress and calcitriol could prevent cells from apoptosis via further activation of autophagy through VDR pathway.

A Narrative Role of Vitamin D and Its Receptor: With Current Evidence on the Gastric Tissues

Vitamin D is a major steroid hormone that is gaining attention as a therapeutic molecule. Due to the general awareness of its importance for the overall well-being, vitamin D deficiency (VDD) is now recognized as a major health issue. The main reason for VDD is minimal exposure to sunlight. The vitamin D receptor (VDR) is a member of the steroid hormone receptors that induces a cascade of cell signaling to maintain healthy Ca²⁺ levels that serve to regulate several biological functions. However, the roles of vitamin D and its metabolism in maintaining gastric homeostasis have not yet been completely elucidated. Currently, there is a need to increase the vitamin D status in individuals worldwide as it has been shown to improve musculoskeletal health and reduce the risk of chronic illnesses, including some cancers, autoimmune and infectious diseases, type 2 diabetes mellitus, neurocognitive disorders, and general mortality. The role of vitamin D in gastric homeostasis is crucial and unexplored. This review attempts to elucidate the central role of vitamin D in preserving and maintaining the overall health and homeostasis of the stomach tissue.

Prodigiosins from a marine sponge-associated actinomycete attenuate HCl/ethanol-induced gastric lesion via antioxidant and anti-inflammatory mechanisms

Gastric ulcer is sores that form in the stomach mucosal layer because of erosion caused by high acid secretion and excessive use of non-steroidal anti-inflammatory drugs. Prodigiosins (PdGs) are red-pigmented secondary metabolites produced by bacteria, including actinomycetes. Butylcycloheptylprodigiosin (1) and undecylprodigiosin (2) were identified and isolated from a crude extract of the actinomycete RA2 isolated from the Red Sea Sponge Spheciospongia mastoidea. Chemical structure of 1 and 2 was determined by NMR and mass spectroscopy. Although their antioxidant and anti-inflammatory properties are known, their effect on gastric lesion is unknown. Therefore, this study aimed to investigate gastroprotective effects of PdGs against HCl/ethanol-induced gastric lesion in rats. Oral pretreatment with PdGs (100, 200, and 300 mg/kg) attenuated severity of HCl/ethanol-induced gastric mucosal injury, as evidenced by decreases in gastric lesion index scores, ulceration area, histopathologic abnormality, and neutrophil infiltration. These effects were comparable to those of omeprazole, a standard anti-gastric ulcer agent. HCl/ethanol-induced gastric erosions was associated with tremendous increases in lipid peroxidation, nitric oxide, and pro-inflammatory cytokines and mediators (myeloperoxidase, interleukin-1β, tumor necrosis factor-α, and cyclooxygenase-2), and with significant decreases in enzymatic and non-enzymatic antioxidant activities. However, PdGs ameliorated gastric inflammation and oxidative stress by downregulating nuclear factor kappa B and inducible nitric oxide synthase expression and upregulating heme oxygenase-1 expression. PdGs prevented gastric mucosal apoptosis by downregulating Bax and caspase-3 expression and upregulating Bcl-2 expression, thereby increasing prostaglandin E2 production. Our results suggested that PdGs exerted gastroprotective effects by decreasing the levels of inflammatory mediators, apoptotic markers, and antioxidants.

Potential Effect of 1,25 Dihydroxyvitamin D3 on Thioacetamide-Induced Hepatotoxicity in Rats

BACKGROUND

1,25 Dihydroxyvitamin D₃ (1,25(OH)₂D₃) modulates inflammation and immune responses. Deficiency of 1,25(OH)₂D₃ was found to be associated with the risk of cancer, cardiovascular disease, osteoarthritis, infections, and autoimmune diseases. This study evaluated the effect of 1,25 dihydroxyvitamin D₃ 1,25(OH)₂D₃ on thioacetamide (TAA)-induced acute liver injury in rats.

MATERIALS AND METHODS

Rats were treated with either saline or 1,25(OH)₂D₃ (0.30 μg/kg; orogastrically) for 15 d. Starting from day 13, TAA (200 mg/kg; intraperitoneally) was given for 3 d. On day 15, all rats were euthanized. Liver and blood samples were collected.

RESULTS

TAA caused severe damage, increased lipid peroxidation with reductions in endogenous antioxidants, increased apoptosis, increased production of reactive oxygen species, and elevated inducible nitric oxide synthase (iNOS), and nuclear factor kappa B (NF-κB) expression in liver. Extent of damage was decreased by 1,25(OH)₂D₃ (P < 0.01). 1,25(OH)₂D₃ attenuated the increase in malondialdehyde (P < 0.01), increase in myeloperoxidase (P < 0.01), increase in chemiluminescence levels (P < 0.05) and apoptotic activity (P < 0.001). Elevated liver iNOS and NF-κB expression in TAA group was also reduced by 1,25(OH)₂D₃ (P < 0.001, for iNOS; P < 0.001, for NF-κB). TAA group revealed high serum aspartate transaminase and alanine transaminase (ALT) activities (P < 0.01, for aspartate transaminase; P = 0.08, for ALT) and reduced albumin levels (P < 0.01) compared with control. 1,25(OH)₂D₃ had no statistically significant effect on these parameters.

CONCLUSIONS

1,25(OH)₂D₃ provides protection against hepatic injury in a rat model of TAA-induced hepatotoxicity via suppression of inflammatory reaction, oxidative stress, and apoptosis.

Theaflavins attenuate ethanol‑induced oxidative stress and cell apoptosis in gastric mucosa epithelial cells via downregulation of the mitogen‑activated protein kinase pathway

Ethanol‑induced diseases of the gastric mucosa are the most common and refractory diseases of gastrointestinal system in clinic, and are mediated by oxidative stress and apoptosis pathways. Theaflavins (TFs) are considered to be antioxidants. The present study aimed to determine the molecular mechanism underlying the ability of TFs to attenuate ethanol‑induced oxidative stress and apoptosis in GES‑1 gastric mucosa epithelial cells. A Cell Counting Kit‑8 (CCK‑8) assay was performed to investigate the cell viability of GES‑1 cells following administration of ethanol (0.5 mol/l) and subsequent treatment with TFs (20, 40 and 80 µg/ml) for specific time intervals. A carboxyfluorescein diacetate succinimidyl ester assay was used to measure proliferation and further investigate the results of the CCK‑8 assay. Flow cytometry was performed to measure reactive oxygen species (ROS) levels and the apoptosis rates of GES‑1 cells. Furthermore, levels of oxidative stress‑associated factors, including malondialdehyde, superoxide dismutase and glutathione, were investigated using commercial kits. Reverse transcription‑quantitative polymerase chain reaction and western blot assays were performed to determine the expression levels of apoptosis‑associated factors, as well as the phosphorylation levels of extracellular signal‑regulated kinase (ERK), c‑Jun N‑terminal kinase (JNK) and p38 kinase (p38). The results of the present study demonstrated that treatment with ethanol inhibited GES‑1 cell proliferation, and enhanced ROS levels and apoptosis rates, potentially via downregulation of B‑cell lymphoma‑2 (Bcl‑2) expression and upregulation of Bcl‑2‑associated X and caspase‑3 expression levels, as well as enhancing the phosphorylation levels of ERK, JNK and p38. However, treatment with TFs was revealed to attenuate the effects of ethanol administration on GES‑1 cells in a dose‑dependent manner. In conclusion, TFs may attenuate ethanol‑induced oxidative stress and apoptosis in gastric mucosa epithelial cells via downregulation of various mitogen‑activated protein kinase pathways.