Improving erectile function of spontaneously hypertensive rats by silencing ROCK2.

OBJECTIVE

To improve the erectile function of spontaneously hypertensive rats (SHRs) by silencing Rho-associated protein kinase 2 (ROCK2).

METHODS

Wistar-Kyoto rats (WKYs) and SHRs injected with 20-μL saline (WKY saline control and SHR saline control; n = 10) or 20 μL of 3 × 10(6) transducing units per milliliter negative control lentivirus (WKY negative control and SHR negative control; n = 10) were set as controls. After selecting the best inhibitory small interference ribonucleic acid (siRNA) by transducing 4 kinds of the lentiviral vector-based siRNA-targeting ROCK2 messenger ribonucleic acid (mRNA) respectively into cultured cavernous smooth muscle cells, 20 μL of 3 × 10(6) transducing units per milliliter of the lentiviral vectors were prepared and injected into the corpora cavernosa of WKYs (WKY siRNA; n = 10) and SHRs (SHR siRNA; n = 10). Seven days later, the maximum intracavernosal pressure to mean arterial pressure ratio (ICPmax/MAP), the expression levels of ROCK2, endothelial nitric oxide synthase (eNOS), and phosphorylated eNOS in the penis were measured and determined.

RESULTS

In cavernous smooth muscle cells of SHR culture, 3 kinds of ROCK2 siRNA significantly inhibited ROCK2 mRNA expression. The lentiviral vector-based siRNA-targeting ROCK2 mRNA at the 2287th nucleotide position significantly increased the ICPmax/MAP in the SHR siRNA group more than in SHR saline control and SHR negative control groups. There was no significant difference in the ICPmax/MAP among WKY saline control, WKY negative control and WKY siRNA groups. The ICPmax/MAP in the SHR siRNA group was significantly lower than that in the WKY saline control group. ROCK2 expression in the penis was significantly decreased in SHR siRNA group compared with that in SHR saline control and SHR negative control groups. The expression of eNOS and phosphorylated eNOS was significantly increased in SHR siRNA compared with that in SHR saline control and SHR negative control groups.

CONCLUSION

The gene therapy with lentiviral vector-based siRNA-targeting ROCK2 mRNA can significantly improve erectile function mainly by directly inhibiting ROCK2 pathway in the SHR.