PTGS2 and Cerebral ischemia: It can clear hydroxyl free radical (COH), nitric oxide free radical (no) and peroxynitrite ion (onoa), and inhibit the expression of tumor necrosis factor-A (TNF-a), interleukin IP (IL-1 (3), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) and other inflammatory related proteins induced by cerebral ischemia [131].