Ageª²related changes of Cx43 proteins in the region around the sinoatrial node of rats

    CHENG Gong, SUN Chaoª²Feng, HUANG Xin, DU Yuan, ZHANG Junª²Bo, WANG Yongª²Hong

    Department of Cardiovascular Disease, First Affiliated Hospital, Medical College, Xi¬ðan Jiaotong University, Xi¬ðan 710061, China

    ¡¾Abstract¡¿ AIM: To observe the change of sinoatrial conduction time(SACT) and protein expression level of Cx43 in the region around sinoatrial nodes(SAN) in neonatal, adult and old SD rats, and to explore the molecular basis of SAN electrophysiological reconstruction. METHODS: The rats were anesthetized, and then ECG was recorded. Esophageal electrode was inserted to count SACT. The SAN was separated and prepared into 10 ¦Ìm continuous frozen sections. Four neighboring sections were taken as a group, and then HE and Masson stainings were performed at the 2 middle sections. Immunohistochemical technology was used for the other 2 sections by FITC marked antibody of HCN4 and Cx43. Cx43 was measured with laser confocal microscope. RESULTS: ¢Ù SACT(ms) was prolonged with ageing(neonatal 15.2¡À2.2, adult 17.6¡À1.6, old 19.3¡À0.9). ¢Ú The expression of Cx43 in the region around SAN decreased with ageing(CT: neonatal 21.3¡À3.9, adult 15.7¡À2.7, old 6.9¡À1.8; Sinus: neonatal 14.2¡À4.2, adult 10.7¡À3.0, old 5.3¡À2.1). CONCLUSION: Cx43 in the region around SAN possibly participates in electrophysiological molecular mechanism of ageª²related SAN functional regression. ......