Acute gastric mucosal injuries--origin of the stress-induced injury? A review

Ethanol-induced gastric ulcer in rats and intervention of tert-butylhydroquinone: Involvement of Nrf2/HO-1 signalling pathway

Gastric ulcer (GU) is the most common health concern that occurs due to alcohol consumption, smoking and physiological stress. Ethanol-induced GU in animal model resembles the pathophysiology of human ulcer. The present study was designed to investigate the cytoprotective and anti-inflammatory properties of tert-butylhydroquinone (tBHQ), a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, against gastric mucosal damage induced by acute exposure of ethanol (5 ml/kg). The intervention of tBHQ (25 and 50 mg/kg, per os (po)) and omeprazole (20 mg/kg, po) was done for 10 consecutive days. Omeprazole was chosen as a standard drug because it is prescribed for the treatment of GU. Pretreatment of tBHQ decreased gastric mucosal lesion, ulcer index, apoptotic cells and lipid peroxidation level induced by ethanol. Furthermore, the intervention of tBHQ increased gastric mucosa integrity, pH, reduced glutathione, collagen and mucus-producing goblet cells. Intervention of tBHQ increased the expression of antioxidant markers such as Nrf2, haeme oxygenase-1 and catalase and decreased the expressions of inflammatory markers such as nuclear factor kappa-light-chain-enhancer of activated B cells and cyclooxygenase-2. The cytoprotective potential of tBHQ against gastric mucosal damage might be due to its ability to enhance cellular antioxidants and anti-inflammatory responses.

Role of sulfhydryl-containing agents in the healing of erosive gastritis and chronic gastric ulceration in the rat

One milliliter of 1, 2, or 5% DL-cysteine (cysteine) or DL-methionine methylsulfonium chloride (MMSC) was instilled into the rat stomach 1, 24, and 48 h after giving ethanol (1 mL of 40% solution) by gavage. One hour following the administration of ethanol, gastric mucosal injury was seen in all the animals (22.6 +/- 1.1 mm2, mean +/- SEM; n = 10). Twenty-four hours after giving the ethanol, all the rats treated with cysteine or MMSC still had the mucosal injury. Treatment with 2% cysteine or MMSC significantly (p less than 0.01) reduced the extent of this injury (10.2 +/- 0.6 and 10.1 +/- 0.5 mm2, respectively, versus 20.7 +/- 1.2 mm2, mean +/- SEM; n = 10), an action that was similarly achieved by the 5% solutions (10.1 +/- 0.5 and 9.9 +/- 0.3 mm2, respectively, versus 20.7 +/- 1.2 mm2, mean +/- SEM; n = 10). Forty-eight hours following the administration of ethanol, 30% of the animals given 1% cysteine or MMSC still had gastric mucosal injury, which was significantly (p less than 0.001) less extensive than that seen with ethanol alone (3.8 +/- 0.3 and 4.1 +/- 0.3 mm2, respectively, versus 13.1 +/- 0.8 mm2, mean +/- SEM; n = 10). At this time period, however, none of the animals treated with 2 or 5% solutions of cysteine or MMSC still had any injury. Healing of the ethanol-induced injury was confirmed microscopically and was achieved by regeneration.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastric mucosal cytoprotection in the rat by scavenging oxygen-derived free radicals

Oxygen-derived free radicals are cytotoxic and promote tissue damage. Dimethyl sulfoxide (DMSO) and allopurinol scavenge hydroxyl radicals, and the latter agent also inhibits the enzyme xanthine oxidase, which is responsible for the formation of superoxide anions. These agents were given daily by gavage (1 ml/d). After 2 days of administration as 1, 2, or 5% solutions, the H+ output of the rat with or without pyloric ligation was not significantly affected. After six hours reserpine (5 mg/kg i.p.) or serotonin (50 mg/kg i.p.) produced ischemic mucosal injury in all stomachs (39 +/- 5.2 mm2 and 25.9 +/- 2.8 mm2, mean +/- standard error of the mean [SEM], n = 10). Pretreatment for 2 days with 1 ml/d of 1% allopurinol or DMSO significantly (p less than 0.001) protected the rat against the reserpine (23 +/- 2.1 mm2 and 24 +/- 1.9 mm2, respectively, vs 39 +/- 5.2 mm2, n = 10) and serotonin injury (10 +/- 1.5 mm2 and 11 +/- 1.8 mm2, respectively, vs 25.9 +/- 2.8 mm2, n = 10). However, 2 days pretreatment with 1 ml/d of 2% allopurinol or DMSO was more effective (p less than 0.001) in this respect, and injury only developed in 40% of the rats given reserpine (8 +/- 1.2 mm2 and 9 +/- 1.6 mm2) and in 20% of those given serotonin (2.4 +/- 0.4 mm2 and 1.9 +/- 0.5 mm2). Similar pretreatment with 5% solutions completely protected the rat stomach against the reserpine and serotonin injuries without significantly influencing the H+ output.(ABSTRACT TRUNCATED AT 250 WORDS)

Protection against stress-induced acute gastric mucosal injury by free radical scavengers

This study investigated whether the free radical scavengers allopurinol (50 mg p.o. q.i.d.) and dimethyl sulphoxide (DMSO, 500 mg p.o. q.i.d.) influence the incidence of stress-induced acute gastric mucosal injury in patients with pelvic fractures and hypovolaemic shock. In 177 fully evaluable patients (control n = 58, allopurinol n = 62, DMSO n = 57), endoscopically proven stress-induced injury evolved in a significantly (p less than 0.01) larger number of controls relative to either group on active therapy. During the first 3 days after hospitalization, 13 controls (22%) developed the injury whereas only 2 patients in each of the allopurinol (3%) and DMSO (4%) groups had this injury. Of these cases, 8 controls (14%) and one patient in the allopurinol group (2%) deteriorated and underwent emergency surgery, however 3 of the controls (5%) died in the immediate post-operative period. The results suggest that oxygen-derived free radicals are directly implicated in stress-induced acute gastric mucosal injury and that removing them protects against this injury and its complications.