MPO and ulcer disease: The ulcerogenic mechanism of indomethacin suggested as accompanied with severe oxidative stress in gastric tissue causing damages to key biomolecules such as lipids, proteins, and DNA leading to increased accumulation of MDA, MPO, and accumulation of reactive products altering enzymatic and nonenzymatic antioxidant parameters leading to enhanced oxidative damage during stomach ulceration [15, 31–34].