Labeled Lipoprotein Clearance Kinetics

In experiment 1, after 6 weeks of treatment, TG-rich lipoprotein-like particles double-labeled with glycerol tri[³H]oleate (American Radiolabeled Chemicals, USA) and [¹⁴C]cholesteryl oleate (American Radiolabeled Chemicals, USA) were prepared as previously described⁴⁷ (link) and injected into the tail vein of the mice (1.0 mg TG in 200 μL saline per mouse). Blood samples were drawn from the tail vein at 2, 5, 10, and 15 min after the particle injection. Subsequently, mice were killed by CO₂ inhalation and perfused with ice-cold PBS before organs were collected. Plasma samples collected following the particle injection and tissue samples that had been dissolved overnight at 55°C in Solvable (PerkinElmer, The Netherlands) were mixed with Ultima Gold liquid scintillation cocktail (PerkinElmer, The Netherlands). ³H and ¹⁴C activity in the samples (disintegrations per minute; dpm) were quantified using a Tri-Carb 2910TR low-activity liquid scintillation analyzer (PerkinElmer, The Netherlands). Decay of ³H and ¹⁴C radioactivity in plasma was expressed as the percentage of injected radioactive dose. Uptake of ³H and ¹⁴C radioactivity by the organs was expressed as the percentage of injected radioactive dose per gram tissue.