Quantitative Analysis of Hepatic Toxicity in Rats Induced by Inhalable Silica Nanoparticles Using Acoustic Radiation Force Imaging.

OBJECTIVES: The purposes of this study were to verify whether inhalable silicon dioxide (SiO2 ) nanoparticles could induce hepatic injury and to investigate the relationship between the exposure time and SiO2 nanoparticle dosage by using acoustic radiation force impulse imaging (ARFI).

METHODS: A total of 72 rats were randomly separated into 9 groups with 8 in each: blank control group, 0.9% normal saline group, polyacrylate (PPE) group, 25%, 50%, and 100% SiO2 groups, and 25%, 50%, and 100% SiO2 /PPE groups with inhaled SiO2 nanoparticle concentrations similar to the SiO2 groups. After successful modeling and design, the hepatic shear wave velocity (SWV) values of the 9 groups were obtained on days 3, 7, 14, 21, and 28 by using ARFI, and the intragroup and intergroups differences in the SWVs were compared. The serum alanine aminotransferase (ALT) and aspartate aminotransferase were tested and compared on day 28. Hepatic tissues were collected for histologic observation on day 28.

RESULTS: The pathologic results verified that inhalable SiO2 nanoparticles could induce hepatic injury. Compared with the control group, the hepatic SWV and serum ALT values in the SiO2 groups and SiO2 /PPE groups were elevated (P < .05). The dosage and exposure time of SiO2 played a key role in the elevation of the SWV in the SiO2 and SiO2 /PPE groups. The correlation between the ALT level and SWV was significant on day 28 (P < .05).

CONCLUSIONS: Inhalable SiO2 nanoparticles and SiO2 /PPE were able to induce hepatic injury in rats. Using ARFI to evaluate hepatic toxicity induced by SiO2 nanoparticles was effective in this study.