Intervention of panax notoginseng saponins on atrial fibrillation in rats via PI3K-AKT signaling pathway

Objective To investigate the effect and mechanism of panax notoginseng saponins (PNS) on atrial fibrillation in rat model. Methods The rats were randomly divided into control group, atrial fibrillation group and intervention group, with 16 rats in each group. Except the control group, atrial fibrillation rat model was established in the other two groups by continuous tail vein injection of acetylcholine 66 μg/ml and calcium chloride 10 mg/ml mixture. From the first day of modeling, PNS 100 μg/g was intraperitoneally injected in the intervention group, while the control group and atrial fibrillation group were intraperitoneally injected with saline of equal volume once a day for 7 days. After 7 days, electrocardiogram was recorded, effective refractory period was detected, and myocardial tissue was stained with Masson staining. The expression of phosphatidyl inositol 3-kinase (PI3K) and protein kinase B (AKT) in myocardial tissue was detected by Western blots. Results After 7 days, atrial fibrillation was observed in atrial fibrillation group, while the duration of atrial fibrillation in intervention group was significantly decreased (24.3 ± 2.6 s vs. 43.2 ± 4.6 s, P<0.05). The ERP time in intervention group was significantly prolonged (95.0 ± 10.0 s vs. 75.5 ± 7.6 s, P<0.05), but it was still lower than that in the control group (P<0.05). Western blots showed that the levels of PI3K and AKT in atrial fibrillation group decreased significantly, while those in intervention group increased significantly (P<0.05). Conclusions PNS could activate PI3K-AKT signaling pathway, reduce the degree of atrial fibrosis, improve ERP and reduce the duration of atrial fibrillation in rats with atrial fibrillation. Key words: Notoginsenoside; Atrial fibrillation; Phosphatidylinositol 3-kinase; Rats