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Effect of androgen deprivation on penile ultrastructure Zhou-Jun SHEN1, Xie-Lai ZHOU1, Ying-Li LU2, Zhao-Dian CHEN1 1Department of Urology, First Affiliated Hospital, 2Department of Endocrinology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University , Hangzhou 310003, China Asian J Androl 2003 Mar; 5: 33-36 Keywords:
|
Group |
n |
T
(nmol/L) |
FT
(pmol/L) |
DHT
(pg/mL) |
A
(control) |
6 |
13.9510.89 |
43.9125.85 |
106.257.3 |
B
(castrated) |
6 |
0.790.51b |
1.830.15b |
48.48.6b |
C
(finasteride) |
6 |
11.035.68 |
47.3332.45 |
47.116.5b |
3.2 Ultrastructure of tunica albuginea
The thickness of tunica albuginea was listed in Table 2. It was significantly thinner in Group B than in Group A (P<0.05), but there was no significant difference between Groups C and A (P>0.05). In Group A (Figure 1), the elastic fibers in tunica albuginea were very rich and arranged regularly and undulatedly, while in Group B (Figure 2), the elastic fibers were mostly replaced by collagenous fibers. In Group C (Figure 3), the regularly-arranged elastic fibers were not seen and replaced by thick and irregularly-arranged collagenous fibers.
Table 2. Thickness of tunica albuginea (meanSD). bP<0.05, compared with control.
Group |
n |
Thickness
(mm) |
A
(control) |
6 |
0.160.03 |
B
(castrated) |
6 |
0.040.01b |
C
(finasteride) |
6 |
0.140.03 |
Figure 1. Ultrastructures of tunica albuginea, Group A. (300)
Figure 2. Ultrastructures of tunica albuginea, Group B. (300)
Figure 3. Ultrastructures of tunica albuginea, Group C. (300)
3.3 Ultrastructure of corpus cavernosum
In Group A (Figure 4a & b), the smooth muscle fibers in the trabeculae were rich and contained a few elastic and collagenous fibers. Structure of the sinusoids was perfect and clear.
Figure 4a & b. Ultrastructures of corpus cavernosum, Group A. (a300, b900)
In Group B (Figure 5a & b), the corpus cavernosum was mainly composed of a large amount of collagenous fibers, which were thick and irregularly arranged. Smooth muscle fibers in the trabeculae were diminished or completely disappeared. The sinusoids were markedly depressed and narrowed.
Figure 5a & b. Ultrastructures of corpus cavernosum, Group B. (a300, b900)
In Group C (Figure 6a & b), the corpus cavernosum also contained a considerable amount of thick and irregularly-arranged collagenous fibers, but the degree of fibrosis was not so marked as in Group B and the types of fibrosis were different between these two groups. The sinusoids of Group C were partially depressed, but the structure of the sinusoids was still retained.
Figure 6a & b. Ultrastructures of corpus cavernosum, Group C. (a300, b900)
4 Discussion
The present study showed that in the castration animals, there were a high degree of fibrosis in the corpus cavernosum with irregularly arranged collagenous fibers and a marked decrease in smooth muscle fibers, while in the DHT-inhibited group, the corpus cavernosum contained quite an amount of thick and irregular-arranged collagenous fibers, but the degree of fibrosis was lower than that in the castration group. Results suggest that androgen is essential for the maintenance of normal ultrastructure of corpus cavernosum. Zhang et al [4] demonstrated that in mature rats, castration induced apoptosis in corpus cavernosum with the replacement of the apoptotic tissues by fibrous tissue. This may be one of the pathways through which androgen deprivation acts on corpus cavernosum. In the present study, the degree and type of corpus cavernosum fibrosis in the two groups were different, suggesting that T and DHT act on the corporal cavernosal tissues independently and differently. Finasteride can only inhibit the action of DHT, but not T on the corporal cavernosal tissue, therefore, the degree of fibrosis was less in the DHT-inhibited group than in the castration group.
The tunica albuginea of penis plays a major role in the erection mechanism. It compresses the subalbugineal venules, thus decreasing the venous outflow during erection and provides an inextensible fibrous frame for the erectile tissue of the penis [5]. In the normal control group of this study, the elastic fibers in the tunica albuginea were very rich and arranged regularly and undulatedly. In the castration group, the thickness of tunica albuginea decreased significantly and the elastic fibers were mostly replaced by collagenous fibers and in the DHT-inhibited group, the elastic fibers were replaced by disorganized and thick collagenous fibers. These results indicate that androgen is also essential for the maintenance of the normal structures of tunica albuginea.
It can be concluded that androgen is indispensable to the maintenance of normal ultrastructures of the erectile tissues. However, the interrelationship between androgen and the structure and function of the erectile tissue is not quite clear and sometimes even controversial, and further investigation is needed.
References
[1] Luisi
M, Franchi F. Double-blind group comparative study of testosterone undecanoate
and testosterone in hypogo-nadal male patients. J Endocr Invest 1980;
3: 305-8.
[2] Shen ZJ, Lu YL, Chen ZD, Chen F, Chen Z. Effects of androgen and aging
on gene expression of vasoactive intestinal polypeptide in rat corpus
cavernosum. BJU Int 2000; 86: 133-7.
[3] Shen ZJ, Jin XD, Chen ZD, Shi YH. Effect of aging on penile ultrastructure.
Asian J Androl 2001; 3: 281-4.
[4] Zhang XH, Hu LQ, Zheng XM, Li SW. Apoptosis in rat erectile tissue
induced by castration. Asian J Androl 1999; 1:181-5.
[5] Goldstein AM, Padma-Nathan H. The microarchitecture of the intracavenous
smooth muscle and the cavernous fibrous skeleton. J Urol 1990; 144: 1144-6.
Correspondence
to: Dr. Zhou-Jun SHEN,
Professor, Department of Urology, First Affiliated Hospital, School of
Medicine, Zhejiang University, Hangzhou 310003, China.
Tel: +86-571-8723 6833, Fax: +86-571-8723 6628
E-mail: shenzhj@mail.hz.zj.cn
Received 2002-09-02
Accepted 2003-02-14