Effects of Mifepristone Solid Lipid Nanoparticles on Cardiac Structure and Function in Rats Undergoing Induction of Labor at Full Term

This research was aimed to analyze the biological characteristics of mifepristone solid lipid nanoparticles (MFP/SLNs) and their effects on the cardiac function of rats undergoing induction of labor at full term (FTIL). MFP was loaded into SLNs to prepare MFP/SLNs. The morphology and particle size (PS) of MFP/SLNs were observed by transmission electron microscopy (TEM), and the PS distribution (PSD) and potential distribution of MFP/SLNs were analyzed by Zeta analyzer. The drug loading (DL) and encapsulation efficiency (EE) of MFP/SLNs were calculated, and the crystal form of the drug in the carrier was detected by differential scanning calorimetry (DSC). Fifteen pregnant rats were randomly rolled into a blank (BLK) group, an MFP group, and an MFP/SLNs group, with five rats in each. Those in the MFP/SLNs and the MFP groups were administered MFP/SLNs (10 mg) and MFP by gavage on the 20th day of pregnancy. The changes in myocardial tissue of rats in the MFP/SLNs and MFP groups were observed within 24 hours after delivery and analyzed by a multifunctional true-color pathological image analysis system. The results indicated that MFP/SLNs had a spherical shape and uniform PSD, with an average PS of about 153 nm. The drug EE of MFP/SLNs exceeded 88% when the drug dosage was 50 mg. The MFP group showed obvious cytoplasmic edema in myocardial cells, an increased average mitochondrial volume density (MVD), and glycogen granule deposition. The area of myocardial cells in the MFP group was obviously larger than that in the MFP/SLNs group ( P < 0.05), and the nuclear-cytoplasmic ratio (NCR) was much smaller ( P < 0.05). These findings suggested that MFP/SLNs were successfully prepared, and MFP can cause changes in the cardiac structure of rats undergoing FTIL, resulting in hypoxic injury. However, MFP/SLNs may protect the cardiac structure and function of rats.