TiO2 Nanoparticles Induce Lung Fibrosis and Proteinosis through Influence on Matrix Metalloproteinase Expression

Background: nanotechnology applications, speared very quickly while very little has been done to measure and assess the hazard of nanoparticles (NPs) to an ecosystem and to the biological systems. Lung exposure to titanium dioxide nanoparticle (TiO2 NP) may induce pulmonary alveolar proteinases and fibrosis through influence on matrix metalloproteinase expression (MMPs). Methods: In order to study this, TiO2 NP was instilled into the lung, then, histopathological alteration and MMPs (MMP-1, MMP-2, Collagen-I) expression using RT-qPCR were assessed at 4 days, a month and 3 months post-instillation. Data were analyzed using ANOVA test and gene expression was normalized to that of housekeeping gene, which was hypoxanthine phosphoribosyltransferase (HPRT). Results: The results showed that TiO2 NP induces acute inflammation in lung tissue after 4 days post-instillation with significantly decrease (p<0.05) in MMPs expression. While inducing fibrosis and proteinosis with significantly increase (p<0.05) in MMPs expression after a month post- instillation. Otherwise, after 3 months post-instillation the fibrosis and proteinosis were decreased and the expression significantly increased (p