Investigation of the protective effects of zinc picolinate in an experimental model of ulcerative colitis

INTRODUCTION AND AIM: Zinc deficiency negatively affects gut health and can worsen the symptoms of ulcerative colitis. It has been suggested that zinc absorption in humans can be enhanced by complexing zinc with picolinic acid. However, there is no literature on the effects of zinc picolinate in the treatment or prevention of colitis. The aim of this study is to investigate the protective effect of zinc picolinate supplementation against colitis damage in an experimentally induced colitis model in rats. MATERIALS AND METHODS: Sprague Dawley male rats (n=35) were randomly divided into five groups: control, colitis, colitis + zinc, colitis + zinc picolinate, and colitis + sulfasalazine. To induce colitis, the rats were fasted for 24 hours and then administered acetic acid (AA). Starting 10 days prior to AA administration, the treatment agents or saline (SF) were administered once daily for a total of 10 doses. Twenty-four hours after the administration of SF or AA, the rats were anesthetized (xylazine: 10 mg/kg; ketamine: 50 mg/kg, i.p.), and intracardiac blood samples were collected to terminate the experiment. RESULTS: In the colitis group pretreated with physiological saline (PS), fecal score, macroscopic damage score, and colon edema score were significantly higher compared to the control group (p<0.01–0.001). Malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity, zonula occludens mRNA expression, TNF-α, IL-6 levels, and histopathological scores increased compared to the control group (p<0.01–0.001), while zinc levels, antioxidant glutathione (GSH) content, occludin-1, and claudin-1 mRNA expression decreased (p<0.01–0.001). Pretreatment with zinc or zinc picolinate suppressed fecal score, macroscopic damage score, MDA, MPO, TNF-α, IL-6 levels, and histopathological damage compared to the colitis group pretreated with PS (p<0.05–0.001), while increasing GSH, occludin, and claudin-1 levels (p<0.05–0.001). CONCLUSİON: In the ulcerative colitis model induced by AA in rats, pretreatment with zinc or zinc picolinate suppressed oxidative damage and inflammation in the colon tissue while preserving barrier permeability. Keywords: Inflammation, Oxidant Damage, Ulcerative Colitis, Zinc, Zinc Picolinate