Wenyang Xiaozheng decoction modulates macrophage polarization via JAK2/STAT3 signaling pathway to reduce renal fibrosis.

Ethnopharmacological Relevance: Wenyang Xiaozheng Decoction (WYXZ), a traditional Chinese medicine formula based on the principles of "warming Yang and resolving blood stasis," has been clinically shown to improve renal function in patients with chronic kidney disease (CKD). However, the precise mechanisms underlying its therapeutic effects remain to be elucidated.

Aim Of The Study: To investigate whether WYXZ alleviates renal fibrosis by modulating macrophage polarization via JAK2/STAT3 signaling.

Materials And Methods: Renal fibrosis was induced in C57BL/6J mice by 5/6 nephrectomy, followed by treatment with WYXZ (4.94 or 9.88 g/kg) or valsartan for 8 weeks. Kidney function (serum creatinine/blood urea nitrogen), histopathology (HE/Masson staining), and macrophage polarization (CD86/CD206 flow cytometry) were assessed. In vitro, RAW264.7 macrophages were polarized to M1/M2 phenotypes and treated with WYXZ-medicated serum (2.5-7.5 %) ± JAK2 agonist Butyzamide or STAT3 shRNA. Inflammatory responses (IL-6/IL-10 secretion by ELISA), polarization status (flow cytometry), and JAK2/STAT3 pathway activation (phosphorylated-JAK2/STAT3 by Western blot) were analyzed. Fibrosis markers (α-smooth muscle actin, α-SMA/collagen I, Col-I) were evaluated in RAW264.7/HK-2 co-cultures.

Results: WYXZ significantly attenuated renal fibrosis and improved kidney function in 5/6 nephrectomized mice, concurrently suppressing M1 macrophage polarization while enhancing M2 polarization. In vitro, WYXZ-medicated serum reduced inflammatory cytokine secretion and inhibited JAK2/STAT3 pathway activation in LPS-stimulated macrophages. These effects were reversed by JAK2 agonism with Butyzamide and abolished through STAT3 knockdown. Critically, in macrophage-renal tubular cell co-cultures, WYXZ diminished fibrotic marker expression via suppression of macrophage JAK2/STAT3 signaling.

Conclusions: WYXZ attenuates renal fibrosis by reprogramming macrophage polarization through JAK2/STAT3 inhibition, validating its traditional use for CKD.