Abstract: Objective: To investigate the influence of magnetic Fe₃O₄ nanoparticles in the expressions of Caveolin-1 and Clathrin Heavy Chain proteins in organ tissues of the rats, and to clarify its mechanism. Methods: Twenty-four Wistar rats were randomly divided into control group, and low,medium and high doses of magnetic Fe₃O₄ nanoparticle groups by weights. 24 h after tail vein injection of different doses of magnetic Fe₃O₄ nanoparticles, the organ tissues were obtained. Western blotting method was used to detect the expressions of Caveolin-1 and Clathrin Heavy Chain proteins in the main organ tissues of the rats. Real-time fluorescent quantitative PCR was used to measure the expressions of Caveolin-1 and Clathrin Heavy Chain mRNA. Results: Compared with control group,the expressions levels Clathrin Heavy Chain protein and mRNA in liver and spleen tissues of the rats in medium and high doses groups were significantly increased (P<0.05).The expression level of Clathrin Heavy Chain mRNA in kidney tissue in high dose group was higher than those in other groups(P<0.05). The Caveolin-1 expression levels in the organ tissues of rats had no statistical differences between various groups (P>0.05).Compared with control group, the Caveolin-1 mRNA expression levels in liver, spleen, and lung tissues of the rats in low,medium and high doses groups were significantly increased (P<0.05);there were no statistical differences in the expression levels in kidney tissue of the rats between various groups(P>0.05). Conclusion: Magnetic Fe₃O₄ nanoparticles could enhance the expressions of Clathrin Heavy Chain in the liver, spleen, and lung tissues of the rats. Endocytosis of Clathrin Heavy Chain protein is one way for magnetic Fe₃O₄ nanoparticles into the liver, lung, spleen cells of the rats.

Key words: Clathrin Heavy Chain, magnetic Fe₃O₄ nanoparticles, Caveolin-1