The Studying On Endocrine Toxicology Effects Of Titanium Dioxide Nanoparticles

Titanium dioxide(Ti O2) nanoparticle is a highly stable, anticorrosive, and photoactive nanoparticle, and is frequently used as an important nanomaterial. However, Ti O2 nanoparticles could induce reactive oxygen species(ROS) after they were entered into the bodies of humans and animals, and thus induce many kinds of diseases. Thus, Ti O2 nanoparticles could also induce toxicology effects to humans and animals.Diabetes is an endocrine system disease, and is usually the product of two distinct abnormalities: abnormal b-cell function and insulin resistance(IR). Increases in ROS induce ever-worsening abnormalities in the pancreatic b-cell, and thus, in insulin synthesis and secretion, which is called type I diabetes. ROS can also increase the phosphorylation of serine/threonline residues in insulin receptor substrate 1(IRS1), interrupting the insulin signal, and is the cardinal feature of type II diabetes. Therefore, ROS played a key role in the pathogenesis of diabetes. However, a question is introduced: Does Ti O2 nanoparticles-increased ROS affects plasma glucose homeostasis in vivo? As far as we are aware, there is no study for these questions.In this study, CD-1(ICR) male mice were administered orally Ti O2 nanoparticles(low-dose, LD, 64 mg/kg body weight per day; and high-dose, HD, 320 mg/kg body weight per day; Control, equal volume PBS). Mice physiological indexes(body weights, food intakes, etc.), and plasma glucose(from tail vein and from heart) were measured. Then the regulation pathways of plasma glucose were measured to analyzed the mechanism of Ti O2 nanoparticles affecting plasma glucose.The results showed that, oral administration of Ti O2 nanoparticles increased ROS levels, and thus increased the plasma glucose of tial vein blood and heart blood, but did not affect plasma insulin secretion in mice. b-cell apoptosis was evaluated by HE staining, but no any significant apoptotic b-cells were found in either LD or HD groups, indicating that Ti O2 nanoparticles did not affect b-cell apoptosis or insulin secretion. Oral glucose tolerance test(OGTT) results showed Ti O2 nanoparticles-increased ROS reduced mice ability of controlling the plasma glucose under the normal insulin secretion condition, thus inducing IR and resulting in increased plasma glucose in mice.