The Abnormal Expression Of MicroRNAs In Atherosclerotic

BackgroundInflammation pathological change is evidenced in the whole process of the development and progression of atherosclerosis. Our previous study showed that mi RNA221/222 was highly expressed in endothelial cells in vitro, which in turn attenuated Ang II-induced inflammatory response of endothelial cells by inhibiting the expression of transcription factor ETS-1.The present study was designed to further explore the roles of mi RNA221/222, together with mi RNA125 b, mi RNA221, mi RNA156, mi RNA23 a and mi RNA22 associated with cardiovascular diseases, in inhibiting the proliferation and inflammatory response of atherosclerotic plaques.The carotid artery plaque quick formation model was established in Apo E-/- mice by silicone tube implantation. Differences in the expression of the above mi RNAs and their target genes between the control and model groups were detected and compared by pathological tissue section technique and fluorescence quantitative PCR, hoping that the results could further elucidate the roles of these mi RNAs in the proliferation and inflammatory reaction of atherosclerotic plaques.Establishment of the model and methods1. The model was established in 10-12 week-old Apo E-/-mice by implanting a silica gel casing whose internal diameter was smaller than that of the carotid artery and fixing a segment of the carotid artery in the 5mm casing to cause its stegnosis. After8-week continuous feeding with high-fat diet, vascular changes and the development of atherosclerosis were observed by H&E and oil red O staining.2. Pathological sections of the control group were stained with H&E, and those of the model group were stained with oil red O to compare differences in pathological changes of the internal walls of the blood vessels between the two groups.3. mi RNA expression in the plaqued blood vessels was detected by fluorescence quantitative PCR.4. Differences in the expression of mi RNAs related to atherosclerosis were detected by microassay technique.ResultsAfter 8-week feeding with high-fat diet, the cervical skin was incised under anesthesia to expose the common carotid artery. Yellow atherosclerotic plaques were seen throughout the lumen of the stegnosed segment of the common carotid artery. The vascular tissue was fixed, dehydrated and stained with red oil O. Different amounts and sizes of foam cells, inflammatory cells and fibrous granulation tissue were seen under the vascular endothelial cells, accompanied with bleeding and lipid deposition within the vascular lumen.Fluorescence quantitative PCR showed that the expressions of miRNA125 b, miRNA23 a and mi RNA 156 in the Apo-E-/-model group were higher than those in the control group. The expression of mi RNA125 b, mi RNA 23 a and mi RNA 156 in the Apo-E-/-model group was about 3, 9 and 7 times as high as that in the control group, respectively.ConclusionIt was discovered in this study that several miRNAs were expressed abnormally in the Apo-E-/-mouse atherosclerosis model, among which the expression of mi RNA125 b,mi RNA 23 a and mi RNA 156 increased exponentially in the vascular tissue of the modeled animals, especially mi RNA 23 a, whose expression was further confirmed by microassay technique, suggesting that mi RNA 23 a may participate in the development and progression of atherosclerosis.