Effects of ZnO nanoparticles on intestinal function and structure in normal/high fat diet-fed rats and Caco-2 cells

The present study was carried out to determine the effects of ZnO nanoparticles (ZnO-NPs) on intestinal function and pathophysiological alteration. ZnO-NPs were synthesized and their characterizations were performed using various techniques. The Wistar male rats fed with normal diet and/or high fat diet (HFD) for 8 weeks and then orally received ZnO-NPs (5, 50 and 100 mg/kg bodyweight) for 28 days. The oxidative stress (SOD, CAT, GPx), inflammatory (TNF-α, iNOS) and apoptosis pathways ( ) genes expression and protein levels were measured by real-time polymerase chain reaction and available kit, respectively. The activity of Caspase-3, antioxidant capacity, as well as inflammatory markers were determined. The histological alterations of the large and small intestine were also evaluated with haematoxylin and eosin (H&E) as well as TdT dUTP nick end labeling (TUNEL) assay. The biochemical factors, viability and antioxidant activity were also determined in Caco-2 cells. It was found that the antioxidant enzymes activity and genes expression markedly increased, while inflammatory and apoptosis pathways and TNF-α levels significantly decreased in the intestine of HFD-fed rats treated with 5 mg/kg ZnO-NPs. Intestinal morphological changes were also restored by 5 mg/kg ZnO-NPs in HFD group. Treatment of rats with 50 and 100 mg/kg ZnO-NPs significantly induced intestinal injury, while treatment with 5 mg/kg ZnO nanoparticle normalized intestinal functions and structure. This study showed the synergistic effects of ZnO-NPs and HFD administration on liver enzyme, oxidative stress, apoptosis, inflammation, morphological changes and cell toxicity.