title: shRNA constructs targeting IGFBP-3 alleviate age related erectile dysfunction in the rat.
abstract: OBJECTIVE
  We investigated whether injecting shRNA constructs targeting IGFBP-3 in the penis of old rats would improve erectile function.
  
  
  METHODS
  The most validated IGFBP-3 shRNA plasmid vector (pGPU6/GFP/Neo-shIGFBP-3) was prepared and injected in penile corpus cavernosum tissue. A total of 30 old (age 24 months) male Sprague Dawley® rats were randomly divided into 3 groups, including 10 each that received phosphate buffered saline only (100 μl), pGPU6/GFP/Neo-shNC (100 μg) and the most validated plasmid constructs pGPU6/GFP/Neo-shIGFBP-3 (100 μg). At 4 weeks the erectile response was measured as intracavernous pressure. The percent of smooth muscle in corpus cavernosum tissue was evaluated. Nitric oxide synthase activity and the cGMP concentration in penile tissue were also analyzed. IGFBP-3 was estimated in penile tissue by Western blot, real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry.
  
  
  RESULTS
  pGPU6/GFP/Neo-shIGFBP-3 corrected the impaired erectile response in aged rats compared with the response in those injected with phosphate buffered saline and pGPU6/GFP/Neo-shNC (each p <0.01). The percent of cavernous smooth muscle was increased in the pGPU6/GFP/Neo-shIGFBP-3 group. Nitric oxide synthase activity and the cGMP concentration were also significantly increased in rats treated with pGPU6/GFP/Neo-shIGFBP-3. IGFBP-3 shRNA effectively reduced IGFBP-3 mRNA and protein expression in penile corpus cavernosum tissue.
  
  
  CONCLUSIONS
  Decreasing IGFBP-3 expression by plasmid expressed shRNA improved erectile function in aged rats. The therapy may modulate smooth muscle integrity and increase the cGMP concentration. This may be a new direction for treating erectile dysfunction in clinical practice.
authors.affiliation: Department of Reproductive Medicine, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China; Department of Urology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China. Electronic address: pxyurol@163.com.
authors.forename: Xiao-Yong
authors.initials: XY
authors.lastname: Pu
authors.affiliation: Department of Reproductive Medicine, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China. Electronic address: w_anmin@yahoo.com.cn.
authors.forename: An-Min
authors.initials: AM
authors.lastname: Wen
authors.affiliation: Department of Urology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Jiu-Min
authors.initials: JM
authors.lastname: Liu
authors.affiliation: Department of Urology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Xiang-Guang
authors.initials: XG
authors.lastname: Zheng
authors.affiliation: Department of Urology, Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Heng-Jun
authors.initials: HJ
authors.lastname: Xiao
authors.affiliation: Department of Urology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Zhan-Ping
authors.initials: ZP
authors.lastname: Xu
authors.affiliation: Department of Urology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Huai-Peng
authors.initials: HP
authors.lastname: Wang
authors.affiliation: Department of Reproductive Medicine, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China; Department of Urology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Reproductive Medicine, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Reng-Li
authors.initials: RL
authors.lastname: Zhang
mesh_terms: D000367:Age Factors; D000818:Animals; D007172:Erectile Dysfunction / Q000628:therapy*; D015316:Genetic Therapy; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics*; D008297:Male; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D034741:RNA, Small Interfering
keywords: RNA; erectile dysfunction; insulin-like growth factor binding protein-3; penis; rats; small interfering