In the present study, we aimed to compare the detoxifying effects of two fat emulsions containing either long-chain triglyceride or a mixture of medium-chain and long-chain triglycerides in the propafenone-poisoned rat model.

Rats were randomly divided into 3 groups according to the fat emulsions used:

long-chain triglyceride-based fat emulsion (LL) group; medium-chain and long-chain triglyceride-based fat emulsion (ML) group; normal saline (NS) group. Propafenone was continuously pumped (velocity=70 mg/kg per h) until the mean blood pressure dropped to 50% of basal level. Then, LL/ML fat emulsions or NS was intravenously infused instantly with a loading-dose (1.5 mL/kg) and a maintenance dose (0.25 mL/kg per min) for 1 h. Subsequently, the propafenone was added to plasma (3.5 μg/mL) in vitro, mixed with three doses of LL or ML (1, 2, or 4%). Finally, after centrifugation, the concentration of propafenone was measured. Rats treated with LL exhibited accelerated recovery, characterized by higher blood pressure and heart rate. Rats in both the LL and ML groups demonstrated decreased propafenone in plasma (time-points: 15, 25, and 60 min). However, rats that received LL showed lower propafenone in myocardial tissue at the end of detoxification treatment. Rats in the ML group had the lowest value of pH, the minimum content of HCO3-, and the highest production of lactic acid at the end. In the in vitro experiments, propafenone decreased more dramatically in the LL group compared to the ML group. Long-chain triglyceride fat emulsion had a better effect on treating propafenone poisoning in rats.