Nitric oxide synthase-mediated sub-chronic injury and recovery in the small intestine of mice after oral administration with halloysite nanotubes

• Published in: Environmental science and pollution research international Vol. 27; no. 15; pp. 17730 - 17737
• Main Authors: Hu, Tingting, Wang, Xiaoqin, Tan, Weihang, Nie, Kai, Xu, Xiaolong
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2020; Springer Nature B.V
• Subjects: Aluminum; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biocompatibility; Chronic toxicity; Contamination; Cosmetics; Cyclooxygenase-2; Drug carriers; Drug delivery; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental effects; Environmental Health; Environmental science; Health risks; In vivo methods and tests; Inflammation; Inflammatory response; Intestine; Nanotechnology; Nanotubes; Nitric oxide; Nitric-oxide synthase; Oral administration; Oxidative stress; Purification; Recovery; Research Article; Side effects; Silicon; Small intestine; Tissue engineering; Toxicity; Waste Water Technology; Water Management; Water Pollution Control; Water purification; Water treatment; Oxidative stress; Inflammatory response; Oral; Toxicity; Halloysite nanotube; Small intestine
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-08314-1

Natural halloysite nanotubes (HNTs) with a hollow lumen have been widely applied in many fields, such as water purification, drug carriers, cosmetics, antibacterial, and scaffolds for tissue engineering. However, their in vivo toxicity is still largely unclear. The aim of this study is to evaluate sub-chronic oral toxicity of HNTs in the small intestine of mice. The results demonstrated that oral HNTs at low dose (5 mg/kg) for 30 days promoted mouse growth with no obvious adverse effect on the small intestine. The promotive effect on mouse growth disappeared after cessation of oral administration of HNTs. Oral HNTs at high dose (50 mg/kg) for 30 days induced aluminum (Al) and silicon (Si) accumulation and oxidative stress in the small intestine, which caused significant increases in the levels of cyclooxygenase-2 (COX-2) and nitric oxide synthase (iNOS) and inflammatory response and iNOS-mediated damages in the organ. Oral HNTs-induced changes in the small intestine at high dose were not observed after a 30-day recovery period. These findings provided the first evidence that oral HNTs-induced sub-chronic toxicity in the small intestine was reversible. The results suggest that HNTs at low concentration in environments have no adverse effect on mice, while there are health risks to mice under severe contamination by HNTs.