Improvement of primary Sjögren's syndrome salivary gland function by Xinfeng capsule and its effect on EGR1-STAT3 signaling pathway

The study was aimed to investigate the effects of Xinfeng capsule (XFC) on tissue morphology, and gland function of the salivary gland (SG) in a primary Sjögren's syndrome (pSS) mouse model. An animal model of pSS was established by inducing SG protein in C57BL/6 mice. SG tissues were collected for tissue sequencing and subsequent experiments to detect the expression of cholinergic receptor muscarinic 3(M3R), early growth response factor 1 (EGR1) and target genes in the SG before and after XFC intervention, with in vitro validation. Downstream targets of the EGR1 gene were predicted and analyzed using data analysis. EGR1 showed high expression and was selected for subsequent experiments. Administration of XFC significantly increased saliva production (P < 0.001) and reduced the extent of lymphatic infiltration observed in SG. Furthermore, the expression of EGR1 was increased in the model group with statistical significance in contrast with the control group but decreased after administration of XFC (P < 0.05). Data analysis predicted the downstream target of EGR1 as signal transducer and activator of transcription 3 (STAT3), which was validated in SG tissues of mice (P < .05). XFC demonstrated a significant improvement in the salivary secretion function of the SG in pSS mice. EGR1 can serve as a biomarker and therapeutic target for pSS.