To observe the changes of the toe joint of the rats with rheumatoid arthritis (RA) and the effects on the expression of the apoptotic pathway of synovial cells.Methods:Except the control group, a total of 50 male Wistar rats were to establish collagen induced arthritis (collagen induced, arthritis, CIA) model, and randomly divided into model group, low dose group, middle dose group and high dose group; the medicine was given after rheumatoid arthritis model was successfully established.The control group and model group were given 6.5 g/kg normal saline, and low dose group, middle dose group and high dose group were given gavage Danggui Niantong Decoction of 6.5 13, 19.5, g/kg.The time of intervention was 28 days.The swelling degree of toe joints was measured by volumetric method, and the number of apoptotic cells was calculated by HE staining of toe joints, and the protein expression of Bcl-2, PI3K and Bax was detected by Western blotting (WB).Results:1）The control group had no toe swelling, compared with the drug 1 d model group, low dose group, middle dose group and high dose groups, there were without statistically significant difference (P>0.05).The administration of the first 7 d-28 d in each dosage group swelling degree was lower than the model group (P<0.05).The swelling degree of the middle and high dose of 14 d-28 d was significantly lower than that in low dose group (P<0.05), and the high dose of 28 d group was higher than that of the swelling degree of the middle dose group (P<0.05).2）In the HE staining of toe joints, the number of apoptotic cells in the control group, model group, low dose group, middle dose group and high dose group increased gradually (P<0.05).3）WB detection showed that the expression of PI3K and Bcl-2 in the model group was upregulated.After administration, the expression of Bax protein was decreased (P<0.05), while the expression of Bax protein was opposite to that of PI3K, and increased with the increase of dose (P<0.05).Conclusion:Danggui Niantong Decoction can effectively improve the joint swelling of rheumatoid arthritis rats, promote the apoptosis of synovial cells and inhibit the process of synovial cell proliferation, and the PI3K pathway plays a key role in the regulation of apoptosis.