Icariin Modulates ENOS Activity Via Effects On Post-translational Protein-protein Interactions To Improve Erectile Function Of Spontaneously Hypertensive Rats

Objective: To explore whether icariin can improve erectile function of spontaneously hypertensive rats by affecting post-translational protein-protein interactions to regulate eNOS activity.Methods: Eight-week-old healthy male SHR rats and Wistar Kyoto rats(WKY)were randomly divided into four groups: SHR control group,SHR+icariin(10mg/kg·d gavage)treatment group,WKY control group,WKY+icariin(10mg/kg·d gavage)treatment group(n = 5).After 4 weeks,the maximum penile intracavernous pressure/mean arterial pressure(ICPmax /MAP),the expression of HSP90,Caveolin-1,Calmodulin,P-eNOS and eNOS in penile cavernous tissue and the content of No and cGMP were measured.The interaction between eNOS and HSP90,Calmodulin and Caveolin-1 was detected by Co-immunoprecipitation.Results: There were no significant differences in body weights and testosterone levels among these groups.The level of MAP in SHR group was significantly higher than that in WKY group(P < 0.05).Weight:(WKY: 297.5 ±3.6g,WKY + Icariin group: 298.2 ± 5.2g,SHR: 301.4 ± 4.6g,SHR + Icariin group: 303.7 ± 6.5g)and serum testosterone value(WKY: 480.1 ± 80.3ng / dl,WKY + Icariin group: 492.3 ± 82.3ng / dl,SHR: 486.7 ± 90.6ng / dl,SHR +Icariin group: 493.0 ± 95.2ng / dl)and MAP(SHR: 184.16±6.84 mmHg,SHR+ Icariin group: 183.38±5.79 mmHg,WKY: 124.69±5.36 mmHg,WKY +Icariin group: 124.83±6.92 mmHg)(P<0.05).Under 0V / 3V / 5V electrical stimulation,ICPmax / MAP in the SHR icariin treatment group(0.08 ± 0.01,0.23 ± 0.07,0.40 ± 0.05)was significantly higher than the SHR group(0.03 ±0.01,0.13 ± 0.03,0.21 ± 0.02)(P<0.05),but lower than the WYK control group(0.16 ± 0.03,0.35 ± 0.05,0.7 ± 0.02)and the WKY icariin treatment group(0.17 ± 0.02,0.37 ± 0.03,0.72 ± 0.02)(P<0.05).Compared with the SHR group,the expression of HSP90,Calmodulin,P-eNOS,eNOS and P-eNOS/ eNOS in the penile cavernous tissue of rats in the SHR+icariin treatment group were significantly increased(P<0.05),and the expression of Caveolin-1was significantly decreased(P<0.05).The NO content(2.16 ± 0.22 ?mol / g)and cGMP concentration(3.69 ± 0.12 pmol / mg)of penile cavernous tissue in the SHR icariin treatment group were significantly higher than those in the SHR group(1.01 ± 0.14 ?mol / g,2.31 ± 0.22 pmol / mg)(P<0.05),but lower than the WYK control group(3.11 ± 0.32 ?mol / g,4.25 ± 0.19 pmol / mg)and the WKY icariin treatment group(3.20 ± 0.11 ?mol / g,4.36 ± 0.28 pmol / mg)(P<0.05).Compared with the SHR group,the interaction between eNOS and HSP90 in the the corpora cavernosa of the rats in the SHR + icariin treatment group was significantly increased(P<0.05),the interaction between eNOS and Caveolin-1 was significantly decreased(P<0.01),and the interaction between eNOS and Calmodulin was not significantly changed.Conclusion: Icariin up-regulates the expression of HSP90 and Calmodulin and Inhibits Caveolin-1 in SHR corpus cavernosum.At the same time,itpromotes the interaction between eNOS and HSP90,inhibits the interaction between eNOS and Caveolin-1,increases P-eNOS/eNOS and promotes the production of endogenous NO,improving the erectile function of SHR.