Improvement in erectile dysfunction after insulin-like growth factor gene therapy in diabetic rats

Xiao-Yong Pu^1,2 , Li-Quan Hu¹, Huai-Peng Wang ² , Yao-Xiong Luo ² , Xing-Huan Wang <sup>2

1</sup> Departments of Andrology and Urology, Zhongnan Hospital, Wuhan University, Hubei, China
² Departments of Urology, Guangdong Provicial People’s Hospital, Guangzhou, China

DOI: 10.1111/j.1745-7262.2006.00215.x

Abstract
Aim: To determine whether adenoviral gene transfer of insulin like growth factor-1 (IGF-1) to the penis of streptozotocin (STZ) induced diabetic rats could improve erectile capacity. Materials and methods: The STZ diabetic rats were transfected with AdCMVβgal or AdCMV-IGF-1. These rats underwent cavernous nerve stimulation to assess erectile function and their responses were compared with those of age matched control rats 1 to 2 days after transfection. In control and transfected STZ diabetic rats IGF-1 were examined by reverse transcription polymerase chain reaction, western blot and histology. The STZ diabetic rats’ penis galactosidase activity and localization were also determined. Results: One to two days after transfection, the β-galactosidase was found in the smooth muscle cells of the diabetic rat penis transfected with AdCMVβgal. One to two days after administration of AdCMV-IGF-1, the cavernosal pressure, as determined by the ratio of maximal intracavernous pressure-to-mean arterial pressure and total intracavernous pressure, was increased in response to cavernous nerve stimulation. Transgene expression was confirmed by reverse transcription polymerase chain reaction, Western blot and histology. Conclusions: Gene transfer of IGF-1 significantly increased erectile function in the STZ diabetic rat. These results suggest that in vivo gene transfer of IGF-1 might be a new therapeutic intervention for the treatment of erectile dysfunction in the STZ diabetic rat.

Keywords: erectile dysfunction; gene therapy; cavernosometry; Insulin like growth factor-1

Correspondence to: Dr Xing-Huan Wang, Departments of Urology, Guangdong Provincial People’s Hospital, Guangzhou, Guangdong, China.
Tel: +86-20-8382-7812 ext. 61112, Fax: +86-20-8382-7712
E-mail: urologistl@126.com
Received 2005-12-04? Accepted 2006-06-01