HMOX1 and Arthritis: Recently, thymoquinone pre-treatment was shown to protect human retinal pigment epithelial cells from hydrogen peroxide-induced oxidative stress by activation of the Nuclear factor erythroid 2-related factor 2 (Nrf2)/ Heme oxygenase-1 (HO-1) pathway [13] and to favorably influence an animal model of arthritis [14].