Interaction of intravenously injected liposomes with mouse liver mitochondria. A fluorescence and electron microscopy study

Abstract Megamitochondria, resulting from cuprizone feeding of Swiss ICR mice, were fluorescent in hepatocytes after the intravenous injection to mice of a liposome-encapsulated acridine orange-DNA complex (AO-DNA). Flow cytofluorimetric analysis of isolated megamitochondria showed that the proportion of liposome-encapsulated AO-DNA which localized in megamitochondria increased from 0.02% of the dose injected per liver cell at 3 min after injection to an average of 0.34% at 1 h after injection. Megamitochondria showed negligible fluorescence by fluorescence activated cell sorting (FACS) analysis when free AO-DNA was intravenously injected. Transmission electron micrographs of mouse liver tissue after intravenous injection of liposomes encapsulating iron dextran showed an association of the liposomes with megamitochondria which appeared identical to liposome association with normal mitochondria. These results support and extend our earlier observation that a fraction of the liposomes injected intravenously into mice associate with mitochondria in the liver, and possibly deliver their aqueous contents there.