Comparative Study
. 2015 Jun;49(3):260-6.
doi: 10.3109/21681805.2015.1021832. Epub 2015 Apr 8.
Affiliations
PMID: 25854820 DOI: 10.3109/21681805.2015.1021832
Comparative Study
Effects of insulin-like growth factor-1 on the relaxation responses of the cavernous smooth muscle from aged rats
Zhan-Ping Xu et al. Scand J Urol. 2015 Jun.
Abstract
Objective: The aim of this study was determine whether intracavernosal injection (ICI) of insulin-like growth factor-1 (IGF-1) protein can improve corpus cavernosal smooth muscle relaxation in aging rats.
Materials and methods: Ten young (4-month-old) and 30 old (24-month-old) Sprague-Dawley male rats were enrolled in the study. The old rats were divided into three groups: vehicle-only (n = 10), IGF-1 1 μg/kg (n = 10) and IGF-1 10 μg/kg treatment groups (n = 10). After 4 weeks of single IGF-1 injection treatment, strips of corporal tissue were precontracted with phenylephrine, and dose-response curves were generated to evaluate endothelial-dependent [acetylcholine (ACh)], endothelial-independent [sodium nitroprusside (SNP)] and electrical field stimulation (EFS) vasoreactivity. The changes in percentage of cavernosal smooth muscle and the concentration of nitric oxide (NO) in penile tissue were also evaluated.
Results: After IGF-1 treatment, the vasoreactivity was significantly improved in both the 1 μg/kg and the 10 μg/kg treatment groups compared with the vehicle-only group at 4 weeks in response to ACh, SNP and EFS (all p < 0.05). The percentage of cavernosal smooth muscle was increased in the IGF-1 treatment groups. The NO concentrations were increased after IGF-1 treatment.
Conclusions: These data demonstrate that ICI of IGF-1 can improve vasoreactivity via endothelium-dependent and endothelial-independent mechanisms in the corpus cavernosum of the aging rat.
Keywords: Cavernosal smooth muscle; insulin-like growth factor-1; intracavernosal injection; rats; vasoreactivity.
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