Characterization of simple and reproducible vascular stenosis model in hypercholesterolemic hamsters

Effects of sorghum rice and black rice on genes associated with cholesterol metabolism in hypercholesterolemic mice liver and intestine

The effects of different proportions of dietary sorghum rice and black rice on the expression of genes related to cholesterol metabolism in mice liver, intestine, and the characteristics of the small intestinal microbiota were investigated. Six types of diets were used to feed C57BL/6 mice: AIN-93M standard diet, high-cholesterol model diet, high-cholesterol and low-dose sorghum grain or black rice diet, and high-cholesterol and high-dose sorghum grain or black rice diet. The results showed that black rice or sorghum grain diets had no effect on the serum TC, LDL-C levels in the hypercholesterolemic mice, whereas these diets decreased serum TG level, and black rice diets increased serum HDL-C level. The diets containing black rice and sorghum grain had no effect on liver TC, TG, HDL-C levels. However, these diets decreased LDL-C levels significantly except high dose of black rice. The black rice or sorghum grain diets reduced the expression of the genes encoding liver 3-hydroxyl-3-methyl-glutarate monoacyl coenzyme A reductase (HMG-CoA-R) and increased the expression of SREBP-2, thereby partially inhibiting the synthesis of cholesterol in liver. The diets containing different proportions of black rice and a low proportion of sorghum grain reduced the expression level of Niemann-Pick type C 1 like 1 (NPC1L1) mRNA and increased the mRNA level of the ATP-binding cassette transporters, ABCG5/ABCG8, in the small intestine, thereby reducing cholesterol absorption. A diet containing a low proportion of black rice promoted the expression of ABCA1 mRNA and increased the expression of high-density lipoprotein (HDL) mRNA, thereby promoting reverse cholesterol transport. Black rice diets significantly increased the relative abundances of microbiota in the small intestine and maintained biodiversity, while sorghum grain had no positive effect on the abundance of microbiota.

Effect of a Synthetic Matrix Metalloproteinase Inhibitor (ONO-4817) on Neointima Formation in Hypercholesterolemic Hamsters

Degradation of extracellular matrix (ECM) proteins plays an important role in the development of vascular remodeling. We investigated the alteration of matrix metalloproteinases (MMPs) on the development of neointima formation and the effect of a newly synthesized MMP inhibitor using hypercholesterolemic hamsters. Endothelial injury was achieved by a catheter in the hamster carotid artery. Two weeks after the injury, neointima was detected in all hamsters. Oral administration (twice a day) of ONO-4817 was started 2 hours before injury and continued for the next 2 weeks. The neointimal area, with appearance of maze-like structures, was markedly reduced by 52.4 +/- 8.4% by treatment with ONO-4817 at a dose of 20 mg/kg per day. The treatment by ONO-4817 (20 mg/kg per day) significantly reduced the indexes of histone H1 on day 1, 5, and 10 and the BrdU index of intimal smooth muscle cells on day 5 and 10, but not on day 1. Whereas DNA synthesis was not reduced by ONO-4817, in vitro SMC migration on the other hand was reduced dose dependently. According to the results of western-blotting analysis, the expressions of MMPs were increased 1 week after injury. Especially, MMP-12 was not detected in hamsters without cholesterol diet, but it was much increased after injury in hypercholesterolemic hamsters. Additionally, active form of MMP-12 increased in the injured artery of hypercholesterolemic hamsters. In conclusion, inhibition of MMPs results in the suppression of neointima following vascular injury via both prevention of SMC migration and SMC proliferation of late phase in hypercholesterolemic hamsters. MMP-12 plays an important role on vascular stenosis in hypercholesterolemia and ONO-4817 could be a useful compound for the therapy for this field.