Study on the effects of zinc oxide nanoparticles on ontypeable Haemophilus influenzae clearance in vitro and in vivo

• Main Authors: Yu-Yi Kuo, 郭昱毅
• Other Authors: Chen-Chen Lee
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/27661402998265231661

碩士 === 中國醫藥大學 === 基礎醫學研究所碩士班 === 100 === Nanoparticles (NPs) were widely employed in our living environments. Among those NPs, zinc oxide nanoparticles (ZnONPs) were commonly used in cosmetics because of the excellent protective effect to ultraviolet. Moreover, ZnONPs also have been used in numerous fields to prevent microbial growth. Nontypeable Haemophilus influenzae (NTHi) is an extracellular Gram-negative and coccobacilli bacteria lacking of capsule that frequently colonizes human respiratory mucosa and often produces localized respiratory tract diseases. Recently, several reports indicated inhalation of ZnONPs may be a risk factor for human health. But only few researches discussed the relationship between NPs and immune responses. In this study, we used in vitro and in vivo platforms to assess the potential effect of NTHi clearance after exposure with ZnONPs. Our data showed that after infection of mice with 1×10 7 NTHi, which survived in bronchial alveolar lavage fluids (BALF) and lung tissues, and the inflammatory cells were infiltrated in lung. After exposure with 140 μg/ml ZnONPs and ZnOMPs for 14 days, we found that the total numbers of inflammatory cells in BALF and lung did not show obviously change compared to only infection with NTHi group. However, our data showed that the numbers of active macrophages and inducible nitric oxide synthase (iNOS) expression were significantly decreased in BALF. In addition, we found that 10 μg/ml ZnONPs reduced macrophage extracellular clearance of NTHi and inhibited nitric oxide production in RAW264.7 cells. Our findings reveal that ZnONPs impair NO production and macrophage activation which may lead to reduce the NTHi clearance.