Abstract: Objective To explore the changes and significance of serum Notch1 and reduced upon activation mormal T expression and secreted (RANTES) in the formation of abdominal aortic aneurysm (AAA). Methods From January 2019 to January 2021,41 patients with AAA were selected as the AAA group.41 healthy volunteers during the same period were selected as the healthy group.The levels of Notch1 mRNA and RANTES in serum were detected by RT-qPCR and ELISA.The expression levels of Notch1 and RANTES proteins in AAA tissues were detected by Western blot.Pearson was used to detect the correlation of continuous variables. Results The levels of Notch1 mRNA and RANTES in serum of AAA patients were (3.85±0.62) and (58.46±5.59)μg/L,which were significantly higher than those of healthy individuals[ (1.04±0.23),(21.07±3.25)μg/L]（P<0.05）.The expression levels of Notch1 and RANTES protein in AAA tissue were (3.24±0.65) and (3.41±0.72) ,which were significantly higher than those in normal abdominal aorta tissue [(1.08±0.21),(1.12±0.23)]（P<0.05）.The level of Notch1 protein in AAA tissue was positively correlated with the level of Notch1 mRNA in serum of AAA patients （r=0.485,P=0.025）,and the level of RANTES protein in AAA tissue was positively correlated with the concentration of RANTES in serum（r=0.506,P=0.016）.In AAA tissue and serum of AAA patients,Notch1 and RANTES showed a positive correlation （r-serum=0.515,P=0.014；r-tissues=0.537,P=0.008）. Conclusion Notch1 and RANTES are over-expressed in serum and tissues of AAA patients,and the two are positively correlated.

Key words: abdominal aortic aneurysm, Notch1, T cells activate and secrete regulatory factors