Study On The Effect And Mechanism Of Baoyuan Jiedu Decoction In Regulating MDSCs And Improving Microenvironment Before Lung Metastasis From TGF-β/CCL9 Pathway

Objective: To observe the inhibitory effect of Baoyuan Jiedu Decoction on the formation of microenvironment before lung metastasis and investigate its mechanism through the TGF-β/CCL9 pathway.Methods: The pre-lung metastasis model of spontaneous breast cancer was replicated in vivo,and the lung metastasis was dynamically monitored by in vivo fluorescence imaging of small animals,respectively,to study the effect of Baoyuan Jiedu Decoction on improving the microenvironment before lung metastasis and inhibiting lung metastasis.The flow cytometry was used to detect the MDSCs content and subgroup distribution in MDSCs,followed by ELISA to detect the TGF-β and CCL9 content,and q RT-PCR,IF and Western Blot to detect the expressions of protein and m RNA of CCR1 in metastatic tumor cells and TGF-β/CCL9 pathway key molecules.Results: Baoyuan Jiedu Decoction could prolong the survival time of tumor-bearing mice,inhibit their body weight loss and tumor growth,reduce the content of TGF-β and CCL9 in serum of model animals,inhibit the expression of m RNA and proteins of key molecules of TGF-β/CCL9 pathway,reduce the content of MDSCs in peripheral blood and spleen of tumor-bearing mice,reduce their recruitment in lung tissue,and inhibit the metastasis of breast cancer to the lung.Conclusion: Baoyuan Jiedu Decoction inhibites the recruitment of MDSCs in the microenvironment before lung metastasis by regulating the expressions of TGF-β/CCL9 signaling pathway-related molecules,thereby improving the microenvironment before fee metastasis,delaying the occurrence and development of tumors,inhibiting tumor metastasis,and prolonging the survival time of tumor-bearing mice.