Expression of Sphingosine 1-Phosphate 1-3 on Penile Cavernous Tissue in Hypertensive and Normotensive Rats

Abstract

To investigate the expression of sphingosine 1-phosphate 1-3 (S1P1-3) on penile cavernous tissues in hypertensive and normotensive rats and its association with erectile function. Ten 14-week-old male spontaneously hypertensive rats (SHRs) and 10 male age-matched normotensive Wistar-Kyoto rats were randomly designated as hypertensive rat group and normotensive control group, respectively. Mean blood pressure, serum testosterone, and maximum intracavernosal pressure/mean arterial pressure (ICPmax-to-MAP ratio) were measured. The expression of S1P1-3, endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (P-eNOS), and rho-associated protein kinase 1-2 (ROCK1-2) was determined in the cavernous tissues of SHRs and Wistar-Kyoto rats by the immunohistochemical study and Western blot. There was no significant difference in body weight and serum testosterone levels between the 2 groups. The MAP in the hypertensive rat group was significantly increased compared with the control group. After 3- and 5-V electrostimulation, the ICPmax-to-MAP ratio in the control group was significantly increased compared with the hypertensive rat group. The protein expression of eNOS, P-eNOS, and S1P1 was significantly higher in the control group than in the hypertensive rat group (P<.05). The protein expression of S1P2, S1P3, and ROCK1-2 was significantly lower in the normotensive control group than in the hypertensive rat group (P<.05). Hypertension may impair the erectile function by means of downregulating the expression of S1P1and upregulating the expression ofS1P2-3 in cavernous tissues of SHRs.