Effect of Aging on Androgen, Penile Structure and Nitric-oxide Synthase in Rat

Yim, Seung Hyuk; Kim, Sae Woong; Kang, Sung Hak

Abstract

PURPOSE: The purpose of this study was to investigate the changes of serum testosterone, intracavernous pressure, expression of nitric-oxide synthase (NOS) and content of penile smooth muscle in aged rat.
MATERIALS AND METHODS
Sprague Dawley rats were used for this study and divided into control and aging groups. Intracavernous pressure was measured by stimulating the cavernous nerve with 10volt, 2.4mA. Expression of NOS was measured by immunohistochemical staining for NADPH (nicotinamide adenine dinucleotide phosphate) diaphorase and the content of penile smooth muscle was measured by Masson's trichrome staining for corpus cavernosum. In each case the stained area-tissue ratio was calculated by computer scanning.
RESULTS
Compared with the control group (3.34-0.25ng/ml), the serum testosterone level of the aged group (1.41-0.37ng/ml) was decreased significantly. Compared with the control group (106.7-13.2cmH2O), the intracavernosal pressure of the aged group (71.2-12.3cmH2O) was decreased significantly. Immunohistochemical staining for NOS showed that NADPH diaphorase was stained as brown nerve fiber. Compared with the control group (40.5-3.1%), NOS activity of the aged group (9.5-2.5%) was decreased significantly. On Masson's trichrome staining, the content of penile smooth muscle was 62.8 3.9% in the control group. Compared with the control group, the smooth muscle content of the aged group (35.2-2.4%) was decreased significantly.
CONCLUSIONS
In conclusion, the factors involved in erectile function were decreased in aged rats.