Transcutaneous Electrical Nerve Stimulation (TENS) Improves the Diabetic Cytopathy (DCP) via Up-Regulation of CGRP and cAMP

The objective of this study was to investigate the effects and mechanism of Transcutaneous Electrical Nerve Stimulation (TENS) on the diabetic cytopathy (DCP) in the diabetic bladder. A total of 45 rats were randomly divided into diabetes mellitus (DM)/TENS group (n = 15), DM group (n = 15) and control group (n = 15). The rats in the DM/TENS and TENS groups were electronically stimulated (stimulating parameters: intensity-31 V, frequency-31 Hz, and duration of stimulation of 15 min) for three weeks. Bladder histology, urodynamics and contractile responses to field stimulation and carbachol were determined. The expression of calcitonin gene-related peptide (CGRP) was analyzed by RT-PCR and Western blotting. The results showed that contractile responses of the DM rats were ameliorated after 3 weeks of TENS. Furthermore, TENS significantly increased bladder wet weight, volume threshold for micturition and reduced PVR, V% and cAMP content of the bladder. The mRNA and protein levels of CGRP in dorsal root ganglion (DRG) in the DM/TENS group were higher than those in the DM group. TENS also significantly up-regulated the cAMP content in the bladder body and base compared with diabetic rats. We conclude that TENS can significantly improve the urine contractility and ameliorate the feeling of bladder fullness in DM rats possibly via up-regulation of cAMP and CGRP in DRG.