Department of Endocrinology, Institute of Zoology, Jagiellonian University, Krakow, Poland.
Acta Vet Scand. 2011 Feb 22;53(1):12. doi: 10.1186/1751-0147-53-12.
The dynamic cross-talk between epididymal cells is hormonally regulated and, in part, through direct cell-to-cell interactions. To date, no information is available regarding possible impact of anti-androgens on the proteins involved in the gap junctional communication within the boar epididymis. Thus, a question arised whether prenatal or postnatal exposure to an anti-androgen flutamide alters the expression of gap junction protein - connexin43 (Cx43) and androgen receptor (AR) expression in the caput, corpus and cauda epididymis and leads to delayed effects on morphology and function of adult pig epididymis.
First two experimental groups received flutamide prenatally on gestational days 20-28 and 80-88 (GD20 and GD80) and further two groups were exposed to flutamide postanatally on days 2-10 and 90-98 after birth (PD2 and PD90). Epididymides were collected from adult boars. Routine histology was performed using hematoxylin-eosin staining. The expression of Cx43 and AR were analyzed using immunohistochemistry and Western blotting. Both analyses were supported by quantitative approaches to demonstrate the variations of the expression levels following the treatment. Apoptotic cells were identified using TUNEL assay.
Histological examination revealed differences in epididymal morphology of flutamide-exposed boars when compared to controls. Scarce spermatic content were seen within the corpus and cauda lumina of GD20, PD2 and PD90 groups. Concomitantly, frequency of epididymal cell apoptosis was significantly higher (p < 0.05) after exposure to flutamide at GD20. Moreover, in GD20, PD2, and PD90 groups, significantly lower AR expression (p < 0.05) was found in the principal and basal cells of the corpus and cauda regions, while in the stromal cells AR expression was significantly reduced (p < 0.05) along the epididymal duct. Concomitantly, a decrease in Cx43 expression (p < 0.05) was noticed in the stromal cells of the cauda region of GD20 and PD2 groups. This indicates high sensitivity of the stromal cells to androgen withdrawal.
The region-specific alterations in the epididymis morphology and scarce spermatic content within the lumina of the corpus and cauda indicate that flutamide can induce delayed effects on the epididymal function of the adult boar by decrease in AR protein levels that results in altered androgen signaling. This may cause disturbances in androgen-dependent processes including Cx43 (de)regulation, however, we can not exclude the possibility that in response to flutamide decreased Cx43 expression may represent one mechanism responsible for functional disturbance of the boar epididymis.
附睾细胞之间的动态串扰受激素调节，部分通过细胞间直接相互作用进行调节。迄今为止，尚无关于抗雄激素对猪附睾中缝隙连接通讯相关蛋白的可能影响的信息。因此，人们提出了一个问题，即产前或产后暴露于抗雄激素氟他胺是否会改变 caput、corpus 和 cauda 附睾中缝隙连接蛋白 - 连接蛋白 43（Cx43）和雄激素受体（AR）的表达，并导致对成年猪附睾形态和功能的延迟影响。
前两组实验动物在妊娠第 20-28 天和第 80-88 天（GD20 和 GD80）接受氟他胺治疗，后两组在出生后第 2-10 天和第 90-98 天（PD2 和 PD90）接受氟他胺治疗。从成年公猪中采集附睾。使用苏木精-伊红染色进行常规组织学检查。使用免疫组织化学和 Western blot 分析 Cx43 和 AR 的表达。这两种分析均采用定量方法来证明治疗后的表达水平变化。使用 TUNEL 测定法鉴定凋亡细胞。
与对照组相比，氟他胺处理的公猪的附睾形态存在差异。GD20、PD2 和 PD90 组的 corpus 和 cauda 管腔中精子含量稀少。同时，GD20 时暴露于氟他胺后，附睾细胞凋亡的频率显著升高（p < 0.05）。此外，在 GD20、PD2 和 PD90 组中，corpus 和 cauda 区域的主细胞和基底细胞中的 AR 表达显著降低（p < 0.05），而在基质细胞中 AR 表达显著降低（p < 0.05）沿附睾管。同时，在 GD20 和 PD2 组的 cauda 区域的基质细胞中发现 Cx43 表达降低（p < 0.05）。这表明基质细胞对雄激素剥夺非常敏感。
附睾形态的区域特异性改变和 corpus 和 cauda 管腔中精子含量稀少表明，氟他胺可通过降低 AR 蛋白水平导致成年公猪的附睾功能发生延迟变化，从而改变雄激素信号。这可能导致包括 Cx43（去）调节在内的雄激素依赖性过程发生紊乱，但是，我们不能排除在氟他胺的作用下，Cx43 表达降低可能是导致公猪附睾功能障碍的一种机制。
