Abstract

BACKGROUND: The aim of this study was to determine if shRNA constructs targeting insulin-like growth factor binding protein-3 can rehabilitate decreased serum testosterone concentrations in streptozotocin-induced diabetic rats.

MATERIAL AND METHODS: After 12 weeks of intracavernous administration of IGFBP-3 shRNA, intracavernous pressure responses to electrical stimulation of cavernous nerves were evaluated. The expression of IGFBP-3 at mRNA and protein levels was detected by quantitative real-time PCR analysis and Western blot, respectively. The concentrations of serum testosterone and cavernous cyclic guanosine monophosphate were detected by enzyme-linked immunosorbent assay.

RESULTS: After 12 weeks of intracavernous administration of IGFBP-3 shRNA, the cavernosal pressure was significantly increased in response to the cavernous nerves stimulation compared to the diabetic control group (p<0.01). Cavernous IGFBP-3 expression at both mRNA and protein levels was significantly inhibited. Both serum testosterone and cavernous cyclic guanosine monophosphate concentrations were significantly increased in the IGFBP-3 shRNA treatment group compared to the diabetic control group (p<0.01).

CONCLUSIONS: These results suggest that IGFBP-3 shRNA may rehabilitate erectile function via increases of concentrations of serum testosterone and cavernous cyclic guanosine monophosphate in streptozotocin-induced diabetic rats.

Keywords: Cyclic GMP - metabolism, Animals, Diabetes Mellitus, Experimental - blood, Diabetes Mellitus, Type 1 - blood, Electric Stimulation, Enzyme-Linked Immunosorbent Assay, Erectile Dysfunction - therapy, Insulin-Like Growth Factor Binding Protein 3 - metabolism, Methyltestosterone - blood, RNA, Messenger - metabolism, RNA, Small Interfering - metabolism, Rats, Rats, Wistar, Real-Time Polymerase Chain Reaction - methods, Signal Transduction, Testosterone - blood