Investigation of the Effects and Mechanisms of Mai Tong Formula on Lower Limb Macroangiopathy in a Spontaneous Diabetic Rat Model

A new Chinese herbal formula called Mai Tong Formulae (MTF) has recently been used to treat lower limb macroangiopathy in type 2 diabetes mellitus (T2DM) patients. In this study, we investigated the effect of MTF on lower limb macroangiopathy in a spontaneous diabetic rat model (GK rats). We found that MTF treatment significantly reduced serum fasting blood glucose (FBG), triglycerides (TG), total cholesterol (TC), IL6, and VEGF and increased serum insulin in this model. Histological and ultrastructural observations showed that MTF treatment significantly reduced vascular endothelial cell shedding and improved endothelium injuries. We further detect proteome alteration following MTF treatment. 25 differential proteins (DPs) abnormally expressed in GK rats were normalized by MTF treatment. These DPs significantly are enriched in biological processes and pathways that regulate muscle contraction and cGMP-PKG signaling pathway and so on. Additional protein-protein interaction (PPI) network analyses of the DPs showed that Fasn and Prkar2a are involved in the AMPK signaling pathway, and Gnas, Myh11, and Myh6 are involved in vascular smooth muscle contraction; these 5 DPs were validated by Western blotting. These results indicate that MTF treatment effectively treats lower limb macroangiopathy by regulating key proteins involved in AMPK signaling pathway and vascular smooth muscle contraction.