Damage to the protein synthesizing apparatus in mouse liver in vivo by magnetocytolysis in the presence of hepatospecific magnetic nanoparticles

Abstract In the previous work, we incubated THP1 cells and macrophages in vitro with unsubstituted ferrofluid (FF) and placed them in an alternating magnetic field. This resulted in the destruction of the cells (magnetocytolysis). Cell-specific magnetocytolysis in vitro was achieved in MCF7 human breast cancer cells incubated with tamoxifen-bound FF and treated in an alternating magnetic field. In this work, in a search of a model for magnetocytolysis in vivo, we injected mice intravenously with hepatospecific magnetic nanoparticles (HS-USPIO) and subjected the mice to magnetocytolysis in an alternating magnetic field (1 h at 200 A/m). This treatment resulted in a prolongation of blood coagulation time due to depletion of protein coagulation factors that are synthesized exclusively in the liver. The attendant derangement of liver protein synthesis was characterized in cell-free preparations by an inhibition of the endogenously coded protein synthesis coupled with an enhancement of phenylalanine polymerization directed by polyuridylic acid (Poly U). This indication of polyribosome dispersion was confirmed by electron microscopy. Magnetocytolysis did not cause liver necrosis and was neither accompanied by any increase in body or liver temperature, nor damage to any other tissue. The effects of magnetocytolysis were proportional to the amount of injected HS-USPIO, field strength and its application time. Magnetocytolysis did not occur when non-magnetic PolyGalactoseGold particles were substituted for HS-USPIO. PolyGalactoseGold particles were employed to measure asialoglycoprotein receptor (ASGP-R) activity in liver using neutron activation analysis. Injection of PolyGalactoseGold particles to mice, pre-treated by HS-USPIO driven magnetocytolysis, revealed a transient diminution of hepatic ASGP-R. Liver damage from magnetocytolysis was followed by liver regeneration, manifested by the appearance of thymidylate kinase activity, diminution of ASGP-R and return to normal blood coagulation time.