Effect Of Lanatoside C On The Development Of Atherosclerotic Plaques

Purpose: Lanatoside C's impact on atherosclerosis is poorly understood. The present study was conducted to determine whether lanatoside C affects the development of atherosclerosis in apolipoprotein E-deficient(Apo E–/–) mice.Methods: Apo E–/– mice on a C57BL/6 background(8 weeks old, 19–22 g) were randomly separated into three groups(n = 14 mice/group). The first group, the vehicle control, was injected with the same volume of PBS containing 0.1% DMSO, while the second and third groups received intraperitoneal injections of approximately 20 ?g of lanatoside C(low-dose, 1 mg/kg per day) or 40 ?g lanatoside C(high-dose, 2 mg/kg per day) and were fed an atherogenic Westerntype diet, containing 0.15% cholesterol and 21% fat, for 12 weeks. Blood samples for lipids were collected retro-orbitally on days 0, 30, 60 and 90 of the study. At the end of the 12-week treatment period, on the day of sacrifice, all animals were anaesthetized intraperitoneally with sodium pentobarbital(50 mg/kg), then exsanguinated via a retro-orbital venous puncture under general anaesthesia. The mice were subsequently euthanized by cervical dislocation. Blood samples were obtained from the animals and stored at-80 °C until further analysis. After the animals were sacrificed, their aortic arches were isolated. To investigate the potential effects of lanatoside C on atherosclerosis, we evaluated the severity of atherosclerosis based on the aortas and aortic sinus by staining with Oil Red O. The plasma levels of total cholesterol, triglycerides, low-density lipoprotein(LDL) cholesterol and high-density lipoprotein(HDL) cholesterol were measured using chemically modified enzyme-based assay. To assess whether lanatoside C promotes atherosclerosis development by inducing SR-A and CD36 in Apo E–/– mice, atherosclerotic lesions were analyzed for SR-A and CD36 expression by western blot. To further explore the effects of lanatoside C on Dil-ox LDL uptake and foam-cell formation, peritoneal macrophages from untreated mice were incubated with lanatoside C for 12 h. The cells were then washed with PBS and incubated with Dil-ox LDL for 4h. The Dil-ox LDL uptake in macrophages were observed on confocal microscopy and flow cytometric analysis. Oil Red O staining was performed to observe foam-cell formation in macrophages from untreated C57BL/6 mice.Results: Lanatoside C dose-dependently aggravated the development of atherosclerosis in the Apo E–/– mice compared with the vehicle control group. No significant changes were observed in the plasma lipids between the treatment groups. However, lanatoside C significantly promoted the uptake of oxidized lowdensity lipoprotein(ox LDL) and increased foam cell formation by upregulation of scavenger receptor class A(SR-A) and the class B scavenger receptor(CD36) in macrophages.Conclusions: Our results provide convincing evidence that lanatoside C aggravates the progression of atherosclerosis in a mouse model of atherosclerosis. These effects appear to be facilitated by increasing ox LDL uptake and foam-cell formation by upregulation of SR-A and CD36..