Gastric mucosa injury quantification in an ischemia - Reperfusion experimental model

The Apelin-Apela Receptor APJ is Necessary for Formation and Healing of Ischemia Reperfusion-Induced Gastric Ulcer in Rats

The apelinergic system, widely expressed and regulates hormone-enzyme secretion, motility, and protective mechanisms of the stomach. This system consists of the apelin receptor (APJ) and two peptides known as apela and apelin. The IR-induced experimental gastric ulcer model, is a well-known and commonly used one that induces hypoxia and causes the release of proinflammatory cytokines. Expressions of apelin and its receptor APJ are induced by hypoxia and inflammation in the gastrointestinal tract. Apelin has been shown to affect angiogenesis positively, considered the most critical component of the healing process. Although it is known that apelin and AJP expressions are induced by inflammatory stimuli and hypoxia, stimulate endothelial cell proliferation and have a role in regenerative angiogenesis, no information or has been found in the literature regarding the role of APJ in the formation and healing of gastric mucosal lesions induced by I/R. So, we conducted a study to clarify the role of APJ in formation and healing mechanisms of IR-induced gastric lesions. Male Wistar rats were divided into five groups; control, sham-operated, IR, APJ antagonist treated-IR group (F13A+IR), and the healing groups. F13A was intravenously given to the animals. Gastric lesion index, mucosal blood flow, PGE₂, NOx, 4-HNE-MDA, HO activity, and protein expressions of VEGF and HO-1 were measured. F13A application before the IR increased the mucosal injury, F13A application following the ischemia delayed the mucosal healing during the reperfusion period. Consequently, blocking apelin receptors may worsen gastric injury due to the IR and delay mucosal healing.

Effect of H2S on gastric ischemia-reperfusion injury in rats

AIM

To assess the effect of H₂S on oxidative stress in gastric mucosal injury induced by gastric ischemia-reperfusion (GI-R) in rats.

METHODS

GI-R was induced in rats by clamping the celiac artery for 30 min followed by 1 h reperfusion. Based on this, the rats were intraperitoneally pre-injected with different concentrations of NaHS for 14 d. Image J software and HE staining were employed to analyze the gastric mucosal damage area and deep damage, respectively. Oxidative stress indexes of the gastric mucosa were detected using commercial kits and Western blot.

RESULTS

The effects of different concentrations of NaHS on gastric mucosal injury induced by GI-R were different. Pretreatment with 10 μmol/L NaHS significantly reduced the area and depth of gastric mucosal injury induced by GI-R, with no effect on plasma H₂S. Compared with the GI-R group, pretreatment with NaHS significantly decreased the levels of malondialdehyde and H₂O₂ as well as the expression of XOD, gp91phox, and p67phox, but increased the level of reduced glutathione and the activity of SOD.

CONCLUSION

Exogenous H₂S can protect the gastric mucosa by reducing oxidative stress induced by GI-R.