Electroacupuncture at ST25 mediated glial cells pruning of pancreatic TRPV1 neural synapse responds to neuropathy-associated beta cell dysfunction.

Electroacupuncture (EA) is verified to modulate glycemic changes in T2DM, and this is partially related to sensory neurotransmitters. However, EA-mediated communication mechanism between them and acupoint specificity have not been fully clarified. Thus, we replicated the diabetic rat model induced by a high-fat diet/streptozotocin (HFD-STZ), and investigated the alleviating effects on insulin resistance (IR) and inflammation severity after EA at ST25. We also compared the effect difference of EA at ST37. Furthermore, we studied the changes of pancreatic sensory neurotransmitters and β cells (and their surrounding components) in detail. Serum glucose, insulin, IR, TNF-α and IL-10 were significantly elevated in model rats, and β cell function was impaired, which reversed by EA at ST25 or ST37 to varying degrees. EA at ST25 can enhance the expression of calcitonin gene-related peptide (CGRP), attenuate transient receptor potential vanilloid 1(TRPV1) and correct the secretion mismatch between them, while EA at ST37 has no such effect. Subsequently, EA at ST25-mediated TRPV1-CGRP-β cell circuit demonstrates an advantage in regulating glucose metabolism via direct insulin inhibition by CGRP. EA at ST25 rather than ST37 regulates the activity of peri-ilset glial cells and macrophages, playing a neuro-protective role and controlling inflammation. EA at ST37 exhibits its partial therapeutic effect on T2DM as it improves serum GLP-1. It also implies that the dominant target organ of ST37 may not be the pancreas, but other associated viscera. Hence, our study elucidates the EA-mediated glial cell via TRPV1-CGRP pathway regulation of β cell dysfunction after nerve lesion, and the hypoglycemic effect of ST25 is significantly better than that of ST37.