Effect of Silicon-enriched meat consumption on proximal colonic antioxidant status of late-stage type 2 diabetes mellitus rats

Colonic mucosa exhibits numerous functional alterations associated to type 2 Diabetes Mellitus (T2DM). Oxidative stress, a factor involved in T2DM pathogenesis and its complications, may contribute to some of the colonic alterations. Silicon (Si) is a trace element with antioxidant, anti-inflammatory and anti-diabetic effects. In this study, we examined if the intake of soluble G⁵ organic Si (2mg/kg b.w./day) as a functional ingredient might enhance the antioxidant status of proximal colonic mucosal barrier in late-stage T2DM rats. A control restructured meat matrix (RM) included in a high saturated-fat hypercholesterolemic diet (HSFHCD-RM) and combined with low-dose streptozotocin plus nicotinamide was used to induce T2DM. Sixteen diabetic rats were divided in two groups and received different experimental diets for 8 weeks: LD group fed a HSFHCD-RM, and LD-Si group fed a Si-enriched RM (HSFHCD-Si-RM). We evaluated Si effects on the immunolocalizations and activities of antioxidant enzymes in proximal colonic mucosa. Compared to LD-group mucosa, LD-Si group showed stronger immunoreactivities in Cu, Zn-superoxide dismutase (SO1) (4.63±0.02 vs. 1.5±0.03; 626%, p=0.00001), Mn-superoxide dismutase (SOD2) (3.63±0.03 vs. 0.5±0.05; 208.6%, p=0.0001), catalase (CAT) (2.38±0.03 vs. 0.75±0.05, 131.51%, p=0.0001), glutathione peroxidase (GPx) (3.25±0.03 vs. 0.5±0.05; 550.0%, p=0.0001) and glutathione reductase (GR) (3.50±0.05 vs. 2.56±0.03; 36.75%, p=0.001). Moreover, Si consumption led to higher total SOD (3.06±0.42 vs. 2.53±0.39; 20.94%, p=0.001), CAT (34.10±1.75 vs. 30.51±1.81; 11.65%, p=0.01) and GR (63.11±13.22 vs. 51.46±9.97; 22.60%, P=0.001) activities; and lower GPx activity (191.82±18.89 vs. 226.61±20.07, 22.63%, p=0.001). In summary, these results demonstrate the enhanced antioxidant status of the proximal colonic mucosa after Si intake in a late-stage T2DM model. Si effectively protected colonic mucosa against oxidative stress induced by T2DM. The incorporation of Si as a functional ingredient could be beneficial as a new nutritional tool to reverse colonic mucosa dysfunction associated to metabolic disorders such as T2DM.