Neither Antioxidants nor COX-2 Inhibition Protect Against Esophageal Inflammation in an Experimental Model of Severe Reflux

In-silico studies on wild orange (Citrus macroptera Mont.) compounds against COVID-19 pro-inflammation targets

One-fifth of COVID-19 patients suffer a severe course of COVID-19 (SARS-CoV-2) infection; however, the specific causes remain unclear. Despite numerous papers that have been flooded in different scientific journals clear clinical picture of COVID-19 aftermath persists to remain fuzzy. The survivors of severe COVID-19infection having defeated the virus are just the starting of an uncharted recovery path. Currently, there is no drug available that is safe to consume to combat this pandemic. However, researchers still struggling to find specific therapeutic solutions. The present study employed an in silico approach to assessing the inhibitory potential of the phytochemicals obtained from GC-MS analysis of Citrus macroptera against inflammatory proteins like COX-2, NMDAR and VCAM-1 which remains in a hyperactive state even after a patient is fully cured of this deadly mRNA virus. An extensive molecular docking investigation of the phyto-compounds at the active binding pockets of the inflammatory proteins revealed the promising inhibitory potential of the phytochemicals. Reasonable physicochemical attributes of the compounds following Lipinski's rule of five, VEBER and PAINS analysis further established them as potential therapeutic candidates against aforesaid inflammatory proteins. MM-GBSA binding free energy estimation revealed that Limonene was the most promising candidate displaying the highest binding efficacy with the concerned VCAM-1 protein included in the present analysis. An interesting finding is the phytochemicals exhibited better binding energy scores with the concerned COX-2, VCAM-1 and NMDA receptor proteins than the conventional drugs that are specifically targeted against them. Our in silico results suggest that all the natural phyto-compounds derived from C. macroptera could be employed in Post covid inflammation complexities after appropriate pre-clinical and clinical trials for further scientific validation.Communicated by Ramaswamy H. Sarma.

Effect of the celexoxib in microscopic changes of the esophageal mucosal of rats induced by esofagojejunostomy

OBJECTIVE

To evaluate the protective effect of celecoxib in the esophageal mucosa in rats undergoing esofagojejunostomy.

METHODS

Sixty male Wistar rats from the vivarium of the University of Health Sciences of Alagoas were used for the experiment. The animals were divided into four groups: Group I, 15 rats undergoing esofagojejunostomy with the use of celecoxib postoperatively; Group II, 15 rats undergoing esofagojejunostomy without the use of celecoxib; Group III, 15 rats undergoing celiotomy with bowel manipulation; and Group IV, 15 rats without surgery and using celecoxib. The observation period was 90 days. After the death of the animals, the distal segment of the esophagus was resected and sent for microscopic analysis.

RESULTS

esofagojejunostomy caused macroscopic and microscopic esophagitis. Esophagitis was equal in both groups I and II. In groups III and IV esophageal lesions were not developed.

CONCLUSIONS

celecoxib had neither protective nor inducing effect on esophagitis, but had a protective effect on dysplasia of the animals of group I.

Analysing the role of COX-2 in acute oesophagitis and in melatonin-exerted protection against experimental reflux oesophagitis in rats†

Objectives

Cyclooxygenase(COX)-2 is implicated in variety of pathophysiological processes, although its role in acute reflux oesophagitis is debatable. This study was designed to evaluate the role of COX-2 during oesophagitis and in melatonin-elicited protection in rats.

Methods

Reflux oesophagitis was induced in rats by ligating the pyloric end and the limiting ridge of the stomach for 5 h. Celecoxib (COX-2 blocker; 10 mg/kg), 16,16-dimethyl prostaglandinE2 (dmPGE2; a synthetic analogue of PGE2; 10 µg/kg), melatonin (20 and 40 mg/kg) and omeprazole (10 mg/kg) were given intra-peritoneally 45 min before induction of oesophagitis in rats. Alterations in COX-1 and 2 gene expression and protein levels level were analysed via RT-PCR and Western blotting, respectively. Mucosal PGE2 level and myeloperoxidase (MPO) activity were measured using an enzyme immunoassay (EIA) kit and spectrophotometrically, respectively.

Key findings

COX-2 over-expression during reflux oesophagitis promotes inflammation of the oesophagus as celecoxib pretreatment significantly reduced tissue damage and MPO activity in rats with reflux oesophagitis (RE-rats). By contrast, dmPGE2 pretreatment significantly exacerbated tissue injury and simultaneously increased COX-2 expression, PGE2 levels and MPO activity in RE-rats. Further, melatonin pretreatment significantly reduced the tissue injury, COX-2 over-expression, PGE2 level and MPO activity in RE-rats. Melatonin offered more potent suppression of COX-2, PGE2 and MPO activity than the proton-pump inhibitor omeprazole; however, both reduced the lesion injury to a similar extent. Melatonin at a dose of 20 mg/kg failed to inhibit significantly the dmPGE2-induced tissue damage, COX-2 expression, PGE2 level and MPO activity in RE-rats while at a higher dose of 40 mg/kg it significantly attenuated these changes.

Conclusion

Our results suggest that COX-2 plays an important pro-inflammatory role during acute reflux oesophagitis in rats and its inhibition contributes significantly to melatonin-exerted protection against reflux oesophagitis.

Pharmacologic concentrations of ascorbate are achieved by parenteral administration and exhibit antitumoral effects

Recently, it has been proposed that pharmacologic concentrations of ascorbate (vitamin C) can be reached by intravenous injection. Because high doses of ascorbate have been described to possess anticancer effects, the therapeutic potential of these concentrations has been studied, both in vitro and in vivo. By using 2-h exposures, a protocol that mimics a parenteral use, we observed that pharmacologic concentrations of ascorbate killed various cancer cell lines very efficiently (EC(50) ranging from 3 to 7 mM). The mechanism of cytotoxicity is based on the production of extracellular hydrogen peroxide and involves intracellular transition metals. In agreement with what has been previously published, our in vivo results show that both intravenous and intraperitoneal administration of ascorbate induced pharmacologic concentrations (up to 20 mM) in blood. In contrast, the concentrations reached orally remained physiological. According to pharmacokinetic data, parenteral administration of ascorbate decreased the growth rate of a murine hepatoma, whereas oral administration of the same dosage did not. We also report that pharmacologic concentrations of ascorbate did not interfere with but rather reinforced the activity of five important chemotherapeutic drugs. Taken together, these results confirm that oral and parenteral administration of ascorbate are not comparable, the latter resulting in pharmacologic concentrations of ascorbate that exhibit interesting anticancer properties.