Erchen Decoction Induces Browning Tendency in White Adipose Tissue of Obese Rats via the SP1/ SREBP/UCP1 Signaling Pathway

OBJECTIVES: Obesity is a global metabolic challenge that leads to excessive fat accumulation and adipose tissue dysfunction due to the disruption of the balance between energy intake and consumption. This study focuses on whether Erchen Decoction promotes high-fat diet-induced white fat browning in obese rats through the SP1/SREBP/UCP1 signaling pathway, thereby improving obesity. METHODS: Male SD rats were fed a high-fat diet to establish an obesity model, and were randomly divided into the High-fat diet (HFD) group, Erchen Decoction low dose, medium dose, high dose groups, and high dose + SP1 inhibitor group. Rats fed a normal diet served as the control group. TC, TG, LDL-C and HDL-C were detected by an automatic biochemical analyzer; the morphology of adipose tissue was observed with HE staining; the expression of SP1, SREBP and UCP1 in adipose tissue was detected with immunofluorescence staining; the mRNA and protein expression levels of SP1, SREBP, UCP1, PPA γ, PGC-1α, p-p65, Fass and ACC in white adipose tissue were detected with Real-time PCR and Western blot respectively. RESULTS: Each dose group of Erchen Decoction and the HD-SP1i group could effectively improve the body weight, blood lipids, and fat tissue morphology of obese rats. After the intervention of Erchen Decoction and HD-SP1i, the expressions of UCP1 and PGC-1α in rat adipose tissue cells were up-regulated, while the expressions of SP1, SREBP, PPA γ, p-p65, Fass, and ACC were inhibited. DISCUSSION: Obesity is a significant global health challenge closely linked to metabolic disorders. According to Traditional Chinese Medicine (TCM) theory, it is often understood as stemming from spleen deficiency leading to the accumulation of phlegm-dampness. Erchen Decoction, a classic TCM formula, achieves its therapeutic effects through the synergistic action of its herbal components, which collectively strengthen the spleen, resolve phlegm, and eliminate dampness. This study demonstrates that Erchen Decoction effectively reduces body weight, improves dyslipidemia, and alleviates pathological changes in adipose tissue in obese rats. The findings indicate that the decoction promotes a "browning" tendency in white adipose tissue, as evidenced by the upregulation of thermogenic markers UCP1 and PGC-1α, and the downregulation of key lipogenic factors SP1, SREBP, Fas, and ACC. These observations suggest that the anti-obesity effects of Erchen Decoction may be mediated through the modulation of the SP1/SREBP/UCP1 signaling pathway, which induces white adipose tissue browning and suppresses lipogenesis. This study provides novel molecular insights into the anti- obesity mechanism of Erchen Decoction, enriching the evidence base for TCM in the treatment of metabolic diseases. Future research should aim to obtain direct histological evidence of UCP1 expression and the formation of multilocular adipocytes, and further explore the effects of the formula on related cellular stress pathways. CONCLUSION: Erchen Decoction may activate the SP1/SREBP/UCP1 signaling pathway and induce browning tendency in white adipose tissue, thereby exerting weight loss.