[Dose and long-term effect of hIGF-1 injection for erectile dysfunction in aged rats].
OBJECTIVE
To investigate the best dose and the long-term effect of the human insulin-like growth factor-1 (hIGF-1) gene injection into the penis of aged rats.


METHODS
Included in this study were 10 young (4 months old) and 40 aged (24 months old) Sprague-Dawley male rats, the latter equally divided into a PBS control and a 10 microg, a 100 microg and a 1 000 microg hIGF-1 injection group. Electrical stimulation was conducted 4 and 8 weeks after hIGF-1 injection into the penile corpus cavernous of the rats to detect the intracavernous pressure (ICP) and mean arterial pressure (MAP). Dose - and time -associated therapeutic results were analyzed and the mRNA expression of hIGF-1 determined by RT - PCR.


RESULTS
ICP, MAP and total ICP were significant decreased by electrical stimulation in the aged rats as compared with the young ones (P < 0.05), statistically increased in the three hIGF-1 dose groups in comparison with the PBS controls (P < 0.05), and showed no obvious difference between the young rats and the latter two dose groups at 4 and 8 weeks. Although less obvious effect was achieved in the 10 microg group than in the young rats, the therapeutic result was still of significance. The mRNA expression of the hIGF-1 gene was confirmed in all the hIGF-1 treated rats.


CONCLUSIONS
The hIGF-1 therapy can improve erectile function in aged rats, 100 microg suffices for effective erection and the effect may last at least 8 weeks for a single dose.
Pu
Xiao-Yong
XY
Department of Urology, Guangdong Provincial People's Hospital, Guangzhou, Guangdong 510080, China. pxyurol@163.com
Wang
Xing-Huan
XH
Wang
Huai-Peng
HP
Gao
Wei-Cheng
WC
Yang
Zhong-Hua
ZH
Li
Shi-Lin
SL
Deng
Chun-Hua
CH
Mao
Xiang-Ming
XM
D000375:Aging / Q000502:physiology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007172:Erectile Dysfunction / Q000503:physiopathology / Q000628:therapy*; D015316:Genetic Therapy / Q000379:methods; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000502:physiology*; D008297:Male; D010413:Penis / Q000378:metabolism / Q000503:physiopathology; D010957:Plasmids / Q000008:administration & dosage / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I