| Objective:To investigate whether low androgen ststus affects erectile function of rat cavernous by regulating eNOS uncoupling.Methods:Thirty-six 8-week-old male Sprague-Dawley（SD）rats were randomly divided into 6 groups as follows:4-week sham-operated group （4w-sham）,4-week castration group（4w-cast）,4-week castration+testosterone（T）group（4w-cast+T）,8-week sham-operated group（8w-sham）,8-week castration group（8w-cast）,8-week castration+T group（8w-cast+T）.Testicles were surgically removed as castration.3mg/kg of T was subcutaneously injected every other day in castration+T groups.The ratio of the maximum intracavernous pressure/the mean arterial pressure（ICPmax/MAP）,the level of serum T,dihydrobiopterin（BH2）,tetrahydrobiopterin（BH4）,nitric oxygen（NO）,3-nitrotyrosine（3NT）,dihydrofolate reductase（DHFR）,guanosine triphosphate cyclohydrolase 1（GTPCH1）,nicotinamide adenine dinucleotide phosphate oxidase 2（NOX2）,and eNOS monomers/dimers in the corpus cavernosum were detected.Results:The level of serum testosterone,BH4/BH2 level,NO content and GTPCH1 decreased significantly in the castration group （4w-cast:1.63±0.17nmol/L;1.49±0.06;6.81±0.48unmol/gprot;0.85±0.06,8w-cast:0.44±0.03nmol/L;0.7±0.04;3.3±0.61unmol/gprot;0.57±0.12）compared with sham-operated groups（4w-sham:20.71±0.55 nmol/L;3.63±0.19;11.27±0.8unmol/gprot;1,8w-sham:20.63±0.47nmol/L;3.55±0.15;11.75±1.98unmol/gprot;1.00±0.03）and castration+testoserone groups（4w-cast+T:20.91±0.84nmol/L;3.56±0.12;12.08±1.98nmol/gprot;1.03±0.04,8w-cast+T:20.65±0.37nmol/L;3.68±0.17;12.67±0.6unoml/gprot;0.99±0.04）（p<0.05）,and 8w-cast was significantly lower than the 4w-cast（p<0.01）.Tthe ratio of eNOS monomers/dimers,the expression of 3NT and NOX2 increased significantly in the castration group（4w-cast:1.01±0.04;53.72±2.12pg/mg;1.42±0.10,8w-cast:1.58±0.02;80.42±2.48pg/mg;1.88±0.19）compared with sham-operated groups（4w-sham:0.58±0.05;38.57±1.35pg/mg;1,8w-sham:0.59±0.02;38.91±0.79mg/pg,0.98±0.07）and castration+testoserone groups（4w-cast+T:0.59±0.02;39.56±2.51pg/mg;1.01±0.10,8w-cast+T:0.58±0.05;36.82±3.34pg/mg;1.02±0.07）（p<0.01）,and8w-cast was significantly higher than 4w-cast（p<0.01）.The expression of DHFR in 4w-cast（1.26±0.02）increased significantly compared with 4w-sham（1）and 4w-cast+testoserone（0.97±0.04）（P<0.01）,the expression of DHFR in8w-cast（0.85±0.03）is significantly lower than 8w-sham（0.98±0.02）and8w-cast+testoserone（0.98±0.06）（p<0.01）and DHFR content in 8w-cast dercreased obviously compared with that in 4w-cast.The ratio of ICPmax/MAP under 3V and 5V in cast groups（3V:4w-cast:0.41±0.02,8w-cast:0.24±0.02,5V:4w-cast:0.55±0.03;8w-cast:0.40±0.01）were significantly lower than that in sham-operated groups（3V:4w-sham:0.66±0.02,8w-sham:0.66±0.04,5V:4w-sham:0.83±0.03,8w-sham:0.85±0.02）and castration+T groups（3V:4w-cast+T:0.65±0.03,8w-cast+T:0.67±0.03,5V:4w-cast+T:0.83±0.01;8w-cast+T:0.81±0.03）（p<0.01）,the ICPmax/MAP ratio under 3V and 5V in 8w-cast was dercreased obviously compared with that in 4w-cast（p<0.01）.Conclusion:Low androgen status induces eNOS uncoupling by reducing BH4/BH2 and increasing 3NT.Due to the decreased NO production,the erectile function of the rats was impaired. |
