■cAMP1激活的交换蛋白(EPAC1)可通过磷酸肌醇3-激酶/蛋白激酶B(PI3K/AKT)途径调节内皮型一氧化氮合酶(eNOS)活性促进血管舒张,并通过抑制ras同源基因家族阻止血管平滑肌收缩,成员A/Rho相关卷曲螺旋形成蛋白激酶(RhoA/ROCK)途径。然而,EPAC1、雄激素与勃起功能之间的关系尚不清楚。因此,我们试图研究EPAC1是否在大鼠阴茎海绵体中表达,以及在低雄激素条件下EPAC1如何影响勃起功能.
■30只8周龄SD大鼠随机分为6组(n=5):假手术(sham),阉割,去势+睾酮替代(去势+T),sham+EPAC1过表达慢病毒(sham+EPAC1),去势+空慢病毒载体(去势+空载体),去势+EPAC1。手术四周后,将携带EPAC1基因的慢病毒载体注射到假EPAC1和去势EPAC1组的阴茎海绵体中(1×108TU/mL,每只大鼠20微升)。注射后一周,最大海绵体内压与平均动脉压之比(ICPmax/MAP)和血清睾酮水平(T),一氧化氮(NO),RhoA的活性形式(RhoA-GTP),AKT,磷酸-AKT(p-AKT),eNOS,磷酸-eNOS(p-eNOS),p-AKT/AKT,测量p-eNOS/eNOS和EPAC1水平。
■与假手术组相比,去势组ICPmax/MAP和EPAC1含量显著降低。EPAC1主要位于大鼠阴茎海绵体内皮细胞和平滑肌细胞的细胞膜和细胞质中。与假手术组相比,T,去势组的ICPmax/MAP和NO水平明显降低(P<0.01)。同时,与去势+空载体组相比,去势+EPAC1组的RhoA-GTP浓度降低(P<0.01)。与阉割+空向量组相比,p-AKT/AKT,去势+EPAC1组EPAC1和p-eNOS/eNOS水平明显升高(P<0.05)。
■雄激素缺乏可以抑制大鼠阴茎海绵体中EPAC1的表达,而其上调可以改善去势大鼠的勃起功能。
UNASSIGNED: Exchange proteins activated by cAMP 1 (EPAC1) can promote vasodilatation by regulating endothelial nitric oxide synthase (eNOS) activity through the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway and prevent vascular smooth muscle contraction by restraining the ras homolog gene family, member A/Rho-associated coiled-coil forming protein kinase (RhoA/ROCK) pathway. However, the relationship among EPAC1, androgen and erectile function is still unknown. Therefore, we attempted to investigate whether EPAC1 expresses in
penile corpus cavernosum of rats and how EPAC1 affects erectile function under low androgenic conditions.
UNASSIGNED: Thirty 8-week-old Sprague-Dawley male rats were randomly divided into six groups (n=5): sham operation (sham), castrated, castrated + testosterone replacement (castrated + T), sham + EPAC1 over-expression lentivirus (sham + EPAC1), castrated + empty lentivirus vector (castrated + empty vector), and castrated + EPAC1. Four weeks after the operation, the lentivirus vectors carrying the EPAC1 gene were injected into the
penile corpus cavernosum of the sham + EPAC1 and castrated + EPAC1 groups (1×108 TU/mL, 20 µL per rat). A week after injection, the ratio of maximum intracavernous pressure to mean arterial pressure (ICPmax/MAP) and the levels of serum testosterone (T), nitric oxide (NO), the active form of RhoA (RhoA-GTP), AKT, phospho-AKT (p-AKT), eNOS, phospho-eNOS (p-eNOS), p-AKT/AKT, p-eNOS/eNOS and EPAC1 levels were measured.
UNASSIGNED: In comparison to the sham group, ICPmax/MAP and EPAC1 content in the castrated group were significantly reduced. EPAC1 is primarily located in the cyto-membrane and cytoplasm of endothelial cells and smooth muscle cells in the rat
penile corpus cavernosum. In comparison to the sham group, the T, ICPmax/MAP and NO levels of the castrated group were significantly reduced (P<0.01). Meanwhile, the RhoA-GTP concentration in the castrated + EPAC1 group was reduced in comparison with the castrated + empty vector group (P<0.01). Compared with the castrated + empty vector group, the p-AKT/AKT, EPAC1 and p-eNOS/eNOS levels in the castrated + EPAC1 group were significantly increased (P<0.05).
UNASSIGNED: Androgen deficiency can suppress EPAC1 expression in the
penile corpus cavernosum of rats, while the up-regulation of which can improve the erectile function of castrated rats.