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| Author(s): |
Carla Dal Bianco Fernandez
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2006-09-15 |
| Examining board members: |
Wilma De Grava Kempinas;
Maria Christina Werneck de Avellar;
Eliana Milanesi Rubio
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| Advisor: | Wilma De Grava Kempinas |
| Abstract | |
The epididymis is an organ of the male reproductive system where sperm undergoes the maturation process, acquiring motility and fertility capacity. The epididymal sperm transit time (number of days necessary for the sperm to be transported through the organ) seems to have an important role in sperm maturation, and it seems that an alteration of the duration of this transit can harm the process. Data from the literature show that the exposure of male rats to estrogenic substances, such as diethylstilbestrol (DES), affects the male reproductive system and provokes an acceleration of sperm transit in the epididymis, damaging the fertility of the animals. The aim of present work was to evaluate the influence of altered sperm transit time through the epididymis on sperm parameters and fertility of rats, as well as the role of testosterone in the alterations. For this, two experimental models were used: DES was administered to the rats to accelerate the sperm transit time, and guanethidine, to delay it, through a selective chemical sympathectomy of the male internal organs. Sprague- Dawley adult male rats were divided into four experimental groups: 1) treated with sc injections of DES, for 12 days, 10µg/rat/day, dissolved in corn oil; 2) treated with guanethidine sulfate via ip injections, for 12 days, at the dose of 6.25mg/kg/day, dissolved in saline solution; 3) same treatment as group 1, plus androgen supplementation, using testosterone-filled subcutaneous implants; 4) control animals received the vehicles. Guanethidine treatment delayed the sperm transit time through the epididymal cauda, provoking an increase in the sperm reserves in this region. On the other hand, exposure to DES accelerated the sperm transit time in the epididymis, decreasing the sperm density in both epididymal regions, the caput-corpus and cauda, and diminishing sperm motility. In both cases sperm production was not altered. Testosterone supplementation was able to restore the transit time to values close to normality, since they were higher than in the control rats. The same occurred in relation to sperm motility. Rats exposed to DES presented a trend toward lower fertility after in utero artificial insemination using sperm collected from the proximal cauda epididymidis. Thus, it was concluded that the acceleration of sperm transit time seemed to harm the normal sperm maturation in the rat, decreasing (AU) | |