Ganjiang Huangqin Huanglian Renshen Decoction improves insulin sensitivity by regulating intestinal flora in rats with Type 2 diabetes mellitus

Purpose: To study the effect of Ganjiang Huangqin Huanglian Renshen Decoction (GHHRD) on intestinal microflora and insulin resistance (IR) in type 2 diabetes mellitus (T2DM) rats. Methods: Streptozotocin (STZ) injection was used to establish a rat model of T2DM. The T2DM rats were divided into 5 groups: control, T2DM, T2DM + low-dose traditional Chinese medicine (TCM), T2DM + high-dose TCM, and T2DM + metformin groups. Total DNA kit was used for extraction of total DNA from fecal microorganisms from the T2DM model rats. High-throughput 16S rDNA sequencing was carried out to identify the intestinal flora of T2DM model rats. Fasting plasma glucose (FPG) and fasting serum insulin (FINS) levels were determined by a biochemical analyzer. Results: The 16S rDNA sequencing analysis showed that after GHHRD treatment, the levels of Ruminococcus, Prevotellaceae, Escherichia-Shigella and Bacteroidota in the intestinal tract of T2DM model rats exhibited significant changes. Furthermore, GHHRD decreased the Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) index and IR in T2DM model rats. Conclusion: GHHRD mitigates IR in T2DM model rats through alterations in the intestinal flora of the rats. This provides a theoretical basis for the potential use of GHHRD in the clinical management of T2DM.