Changes in Protease-Activated Receptor and Trypsin-1 Expression Are Involved in the Therapeutic Effect of Mg[sup.2+] Supplementation in Type 2 Diabetes-Induced Gastric Injury in Male Adult Rats

Purpose. Gastric inflammation is common and usually severe in patients with type 2 diabetes mellitus (T2DM). Evidence suggests protease-activated receptors (PARs) are a link between inflammation and gastrointestinal dysfunction. Given that magnesium (Mg[sup.2+]) deficiency is a highly prevalent condition in T2DM patients, we assessed the therapeutic role of Mg[sup.2+] on the factors involved in gastric inflammation in T2DM. Methods. A rat model of T2DM gastropathy was established using a long-term high-fat diet+a low dose of streptozocin. Twenty-four rats were divided into control, T2DM , T2DM+insulin (positive control), and T2DM+Mg[sup.2+] groups. At the end of 2-month therapies, changes in the expression of gastric trypsin-1, PAR1, PAR2, PAR3, PI3K/Akt, and COX-2 proteins were measured by western blot. Hematoxylin and eosin and Masson's trichrome staining were used to detect gastric mucosal injury and fibrosis. Results. The expression of trypsin-1, PAR1, PAR2, PAR3, and COX-2 increased in diabetes, and Mg[sup.2+]/insulin treatment strongly decreased their expression. The PI3K/p-Akt significantly decreased in T2DM, and treatment with Mg[sup.2+]/insulin improved PI3K in T2DM rats. Staining of the gastric antrum tissue of the insulin/Mg[sup.2+]-treated T2DM rats showed a significantly minimal mucosal and fibrotic injury compared with those of rats from the T2DM group. Conclusion. Mg[sup.2+] supplement, comparable to insulin, via decreasing PARs expression, mitigating COX-2 activity, and decreasing collagen deposition could exert a potent gastroprotective effect against inflammation, ulcer, and fibrotic development in T2DM patients.