Mechanisms of Xuefu Zhuyu Tang in the Treatment of Diabetic Erectile Dysfunction in Rats Through the Regulation of Vascular Endothelial Function by CaSR/PLC/PKC and MEK/ERK/RSK Pathways.

Xuefu zhuyu Tang (XFZYT) is a classic formula used for promoting blood circulation and resolving blood stasis in Traditional Chinese Medicine. Clinical data have indicated that XFZYT plays a significant therapeutic role in diabetes-induced erectile dysfunction (DIED) disease, but the underlying mechanism remains elusive. Male Sprague-Dawley (SD) rats were randomly categorized into normal, model, and treatment groups. The diabetic rat model was established via intraperitoneal injection of streptozotocin. DIED rats were screened using apomorphine, and the number of erections was measured after 8 weeks of XFZYT treatment. Serum nitric oxide (NO) and endothelin-1 levels as well as penile tissue structure alterations were assessed by hematoxylin-eosin staining and electron microscopy. CaSR/PLC/PKC and MEK/ERK/RSK pathway-related proteins in the penile tissue were detected by western blotting (WB) analysis and polymerase chain reaction (PCR). Compared with the blank group, the model group rats showed a significant decrease in weight and erectile function. The pathological damage in the penile tissues of the model rats was indicated by a significantly decreased serum NO level and an increased endothelin-1 content. After treatment with XFZYT, the protein expression of CaSR, PLCβ1, PKCβ, MEK1, ERK1, and RSK1 in the penile tissue was significantly increased. Overall, the treatment group showed significant improvements in the evaluated indexes. In conclusion, this study revealed that XFZYT improves erectile function in diabetic rats, and the underlying mechanism might be linked with the regulation of CaSR/PLC/PKC and related molecules of the MEK/ERK/RSK pathway, which promotes the vascular endothelial diastolic effect.