The present invention discloses a pharmaceutical composition comprising a
circular RNA and a
drug delivery carrier. Compared with traditional linear 1 * siRNA and annular 1 * siRNA, the number of repeated series connection of positive-sense strands is increased to include but not limited to two or more, it is accidentally found that the
silence effect is remarkably enhanced, the expression level of the PCSK9
gene can be remarkably reduced, and degradation of mRNA of PCSK9
protein is mediated. The nano-particles are used for delivering
oligonucleotide, so that the stability is improved, the
immunogenicity is reduced, the effects of lowering
cholesterol, reducing aortic plaque load and resisting atherosclerosis are improved, and the nano-particles are safe and free of obvious
liver and kidney toxicity and have a wide application prospect in the aspect of preparing medicines for treating hypercholesterolemia and
coronary heart disease.