Specific MicroRNAs In Sinus Node Tissue Compared With Atrial And Ventricular Myocytes Tissue Of Mouse

Objective:to observe the specific microRNAs of Kunming mice sinus node tissue compared with atrial myocytes and ventricular tissue. Methods:1. Preliminary experiment to ensure accurate anatomical localization:We Selected 10 Kunming mice weighing between 35-45g whose ages are between 60 and 90 days and ignored male and female. Anesthetized mice were removed the sinus node, left atrial appendage and apical ventricular myocytes by the method of anatomical localization and the tissues were made to about 2 μm paraffin-embedded serial sections, then HE staining was used to observed under an optical microscope and confirm the accuracy of the drawn parts.2. Experiments drawn:Ignored male or female 180 Kunming mice weighing between 35-45g whose ages are between 60 and 90 days were selected. These mice were drawn twice; each time 90 mice were drawn and each mouse were drawn to derive the tissue of the sinus node, left atrial appendage, ventricular myocytes. The tissues of sinus node were drawn by the method corrected and confirmed by the pre-experiment. The left atrial appendages were taken as the tissue of atrial myocytes, and we taken apical ventricular tissue as ventricular myocytes.3. MicroRNA expression profile was detected:classified and marked derived samples were sent to be detected. Total RNA was extracted from samples, then extracted RNA’s quality has been tested and hybridized with microRNA microarrays. These chips were scanned by the fluorescence image scanner and data were analyzed to filter out those specific microRNAs. Results: 1. Results of samples’HE staining:9 mice’s sinus nodes were completely drawn and most of the sinus node’s tissue was drawn out from the other mouse. The cytoplasmic of the cells of sinus node tissue is light dye. A small number of cells gather. The nucleus is large, round and central distribution. Compared with the ordinary myocardial cells, stripes were hardly seen from the cells and large amount of fibrous connective tissue is around the cells. A sinus node artery is visible during the tissue. Mice’s sinus node localization is bounded crest for the longitudinal axis, superior vena cava and the left atrium at the junction of the range of 1.5×2×1mm3. Results of the MicroRNA microarray showed:12 microRNAs including mir-214, mir-147, mir-1900 were significantly upregulated and 27 microRNAs including mir-654, mir-3968, mir-467b, mir-3081, mir-142, mir-1894, mir-497, mir-5114, mir-346, mir-3096a were significantly downregulated in sinus node tissue. Conclusions:1. The method of anatomical localization could accurately obtain the sinus node of mouse.2. The method to detect MicroRNAs expression profile of tissues of the sinus node, atrial and ventricular myocytes is scientifically and credible.312 microRNAs including mir-214, mir-147, mir-1900 were significantly upregulated and 27 microRNAs including mir-654, mir-3968, mir-467b, mir-3081, mir-142, mir-1894, mir-497, mir-5114, mir-346, mir-3096a were significantly downregulated in sinus node tissue. These microRNAs may be the key factors of regulating Cardiac stem cells (CSCs) differentiation to pacemaker cells and further study is worthy to carry out.