title: Nanocrystalline cerium dioxide efficacy for gastrointestinal motility: potential for prokinetic treatment and prevention in elderly.
abstract: BACKGROUND
  Constipation is a common condition, with prevalence after 65 years, is a major colorectal cancer risk factor. Recent works have demonstrated advances in personalized, preventive nanomedicine, leading to the construction of new materials and nanodrugs, in particular, nanocrystalline cerium dioxide (NCD), having strong antioxidative prebiotic effect. The aim of our study was to investigate the influence of NCD on motor function of the stomach and colon in vivo and contractive activity of smooth muscles in different year-old rats.
  
  
  METHODS
  We included 80 rats: 3- (weight 130-160 g, n = 40) and 24-month old (weight 390-450 g, n = 40), divided into four groups as follows: І-control group; rats of II-ІV groups were injected intragastrically one injection per day during 10 days, 3 ml of water 3 ml/kg stabilizing solution, аnd 1 mmol/ml NCD, respectively. In all animals, we recorded spontaneous and carbachol-stimulated (0.01 mg/kg) gastrointestinal tract motor activity. We used the index of motor activity (IMA), expressed in cmH2O, for characterization of the motor function. We investigated smooth muscle contraction by tenzometric method, studied the spontaneous and stimulated motility by ballonographic method.
  
  
  RESULTS
  IMA reduced by 21.1 + 0.2% (p < 0.01) in the old rats of the control group compared with the young rats. A 10-day administration of NCD increased IMA in the stomach of young rats by 9.3% (р < 0.001) vs the control group. The exposure of NCD increased the amplitude of contraction to 34.2 ± 5.4 mN (n = 10) in the stomach of old rats and increased by 32.1 ± 2.4% vs the control group (p < 0.05). NCD did not influence acetylcholine (ACh) contractions in the stomach of young rats; however, in the stomach of old rats, V nr increased by 90 ± 15.2% (р < 0.001).
  
  
  CONCLUSIONS
  The index of motor activity is decreased in old rats. Nanocrystalline cerium dioxide increased the index of motor activity in all groups of rats and also evoked a significant increase of colon contractions in old rats.
authors: Taras Shevchenko National University of Kyiv, Volodymyrska Str., 64/13, 01601 Kyiv, Ukraine.
authors: Olena Yu
authors: OY
authors: Yefimenko
authors: Taras Shevchenko National University of Kyiv, Volodymyrska Str., 64/13, 01601 Kyiv, Ukraine.
authors: Yuliya O
authors: YO
authors: Savchenko
authors: Taras Shevchenko National University of Kyiv, Volodymyrska Str., 64/13, 01601 Kyiv, Ukraine.
authors: Tetyana M
authors: TM
authors: Falalyeyeva
authors: Taras Shevchenko National University of Kyiv, Volodymyrska Str., 64/13, 01601 Kyiv, Ukraine.
authors: Tetyana V
authors: TV
authors: Beregova
authors: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Zabolotny Str., 154, 03680 Kyiv, Ukraine.
authors: Nadiya M
authors: NM
authors: Zholobak
authors: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Zabolotny Str., 154, 03680 Kyiv, Ukraine ; LCL 'DIAPROF', Svitlycky Str., 35, 04123 Kyiv, Ukraine.
authors: Mykola Ya
authors: MY
authors: Spivak
authors: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Zabolotny Str., 154, 03680 Kyiv, Ukraine.
authors: Oleksandr B
authors: OB
authors: Shcherbakov
authors: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Zabolotny Str., 154, 03680 Kyiv, Ukraine ; Clinical Hospital 'Pheophania' of State Affairs Department, Zabolotny Str., 21, 03680 Kyiv, Ukraine.
authors: Rostyslav V
authors: RV
authors: Bubnov
keywords: CRC prevention; Colon; Gastrointestinal cancer prevention; Gastrointestinal motility; Nanocrystalline cerium dioxide; Personalized medicine; Predictive; Preventive; Prokinetic; Rat model; Smooth muscle; Stomach