Integrated serum pharmacochemistry and network pharmacological analysis used to explore possible anti-rheumatoid arthritis mechanisms of the Shentong-Zhuyu decoction

Shentong-Zhuyu decoction (STZYD) has been recognized by the Chinese National Administration of Traditional Chinese Medicine (TCM) as a classic TCM formula. Use of STZYD has shown a satisfactory clinical therapeutic outcome for rheumatoid arthritis (RA); despite this, its bioactive chemical composition and relevant mechanism(s) of this action have not been clearly elucidated. To explore the bioactive chemical composition of STZYD used for RA treatment and its possible mechanism(s) of action. Serum pharmacochemistry mediated by the UPLC-Q-Exactive MS/MS method was employed to identify the absorbed phytochemical compounds in serum derived from STZYD, which were commonly considered as the potential bioactive compounds. And then, these components were used to construct a compound-target network for RA using a network pharmacology approach, to predict the possible biological targets of STZYD along with potential signaling pathways. Afterwards, we established a Complete Freund's adjuvant (CFA)-induced RA rat model, and observed the anti-RA effect of STZYD by a series of indexes, including foot swelling, ankle diameter, arthritis score, morphological and radiographic analysis, serum inflammatory factors, and histopathological analysis of synovial tissues. Particularly, the predicted pathway by the combination of serum pharmacochemistry and network pharmacology was further validated using RT-qPCR, Western blot, and immunohistochemical analyses in animal experiment. Totally, 38 compounds derived from STZYD have been identified by serum sample analysis. Based on it, 387 genes related to these identified compounds in STZYD and 3807 genes related to RA were collected by network pharmacology. Critically, KEGG analysis indicated that the PI3K/AKT signaling pathway was recommended as one of the main pathway related to anti-RA effect of STZYD. Experimentally, STZYD significantly alleviated CFA-induced arthritis without any visible side-effects. Compared to the RA model group without any treatment, the treatment of STZYD significantly reduced the expression of both mRNA and protein targets in the PI3K/AKT signaling pathway. Furthermore, this result was also corroborated by immunohistochemistry analysis. All these studies could effectively corroborate the predicted result as above, suggested that the feasibility of this integrated strategy. This study provided a useful strategy to identify bioactive compounds and the potential mechanisms for TCM formula by integrating serum