Guangdong Provincial People's Hospital-Department of Urology, Guangzhou, Guangdong, China.
J Sex Med. 2011 Aug;8(8):2181-90. doi: 10.1111/j.1743-6109.2011.02318.x. Epub 2011 May 19.
Previous studies have confirmed the gene transfer of insulin-like growth factor-1 (IGF-1) and the IGF-1 protein can improve the erectile function in aging rats. IGF binding protein (BP)-3 can regulates the availability of IGF-I. The higher expression of IGFBP-3 may play an important role in erectile dysfunction (ED).
The study aimed to investigate the mRNA and protein expression of IGFBP-3 in young and old rat penile tissues and assess the alteration of the penile structure and the NO-guanosine 3',5'-cyclic-monophosphate (cGMP) signaling pathways-related marker in ED associated with aging.
The main outcome measures for this study were the expression of IGFBP-3, morphological changes, NO-cGMP signaling pathways-related marker, erectile responses were determined.
Traditional reverse transcriptase polymerase chain reaction (RT-PCR) and real-time PCR were performed to examine the mRNA expression of the IGFBP-3. The Western blot was used to confirm the protein expression. Immunohistochemistry was also performed to identify the cellular localization of the encoded protein. The percentage of smooth muscle in corpus cavernosum tissue, the activity of nitric oxide synthase (NOS), and concentration of cGMP in penile tissue were also analyzed.
The expression levels of IGFBP-3 of mRNA and protein were greatly increased in aging rats compared with young control rats, which is confirmed by traditional RT-PCR, real-time PCR, and Western blot (P < 0.01, respectively). Increased IGFBP-3 protein was localized to the epithelium of the urethra, penile endothelium, and smooth muscle in the corpus cavernosum. Significant depletion of the smooth muscle density relative to the connective tissue was also observed in the penis of the aged rats, and the lower activity of NOS and lower concentration of cGMP was also demonstrated accompanied with a significant reduction in the intracavernous pressure.
Our data suggest that the increased mRNA and protein expression of IGFBP-3 in old rats may play a role in ED.
先前的研究已经证实胰岛素样生长因子-1（IGF-1）的基因转移和 IGF-1 蛋白可以改善衰老大鼠的勃起功能。胰岛素样生长因子结合蛋白（BP）-3 可以调节 IGF-I 的可用性。IGFBP-3 的高表达可能在勃起功能障碍（ED）中发挥重要作用。
本研究旨在探讨 IGFBP-3 在年轻和老年大鼠阴茎组织中的 mRNA 和蛋白表达，并评估与衰老相关的 ED 中阴茎结构和一氧化氮-鸟苷 3'，5'-环化一磷酸（cGMP）信号通路相关标志物的改变。
本研究的主要观察指标是 IGFBP-3 的表达、形态变化、NO-cGMP 信号通路相关标志物、勃起反应。
采用传统逆转录聚合酶链反应（RT-PCR）和实时 PCR 检测 IGFBP-3 的 mRNA 表达。采用 Western blot 法证实蛋白表达。免疫组织化学法也用于鉴定编码蛋白的细胞定位。还分析了海绵体组织中平滑肌的百分比、一氧化氮合酶（NOS）的活性和阴茎组织中 cGMP 的浓度。
与年轻对照组大鼠相比，衰老大鼠的 IGFBP-3 mRNA 和蛋白表达水平均显著升高，这通过传统 RT-PCR、实时 PCR 和 Western blot 得到证实（P<0.01，分别）。增加的 IGFBP-3 蛋白定位于尿道上皮、阴茎内皮和平滑肌组织。还观察到衰老大鼠阴茎中平滑肌密度相对于结缔组织的显著减少，并且 NOS 的活性和 cGMP 的浓度也降低，同时伴随着海绵体内压的显著降低。
我们的数据表明，老年大鼠中 IGFBP-3 的 mRNA 和蛋白表达增加可能在 ED 中起作用。
