长期隐睾症对生殖细胞凋亡和睾丸精子计数的影响。

Effect of prolonged cryptorchidism on germ cell apoptosis and testicular sperm count.

作者信息

Barqawi Albaha, Trummer Herald, Meacham Randall

机构信息

Division of Urology, Department of Surgery, University of Colorado School of Medicine, Denver, CO 80262, USA.

出版信息

Asian J Androl. 2004 Mar;6(1):47-51.

PMID:15064834

Abstract

AIM

To evaluate the long term effect of experimental cryptorchidism on germ cell apoptotic rate and testicular sperm content in adult rats.

METHODS

Bilateral cryptorchidism was created in 40 adult male Sprague-Dawley rats by surgically manipulating the testes into the abdominal cavity and closing the internal inguinal ring. The rats were sacrificed and the testes removed 6 hours and 2, 4, 7, 21, 28 and 56 days after cryptorchidism. Germ cell apoptosis was quantified by means of TUNEL assay and apoptosis was confirmed using transmission electron microscopy.

RESULTS

The rate of apoptosis peaked at 4 days of cryptorchidism and then progressively declined to a nadir at 14 days of cryptorchidism. At 56 days of cryptorchidism, the germinal epithelium was largely depleted by the apoptotic process and only a few mature sperm were seen within the testis. At this point, a few tubules were seen to be repopulating with primary spermatocytes and the level of germ cell apoptosis began to increase marginally. Testicular sperm count (TSC) began to decline rapidly at day 7 of cryptorchidism. Only a few mature sperm were found in the testes of rats following 56 days of cryptorchidism. Multinucleated giant cells (MGC) were most numerous within the seminiferous tubules at day 4. At day 7, 35 % of MGCs were TUNEL positive. At all subsequent time points, however, MGCs fail to stain positive for apoptosis. This resumption of increased apoptosis coincided with the appearance of a population of primary spermatocytes in some seminiferous tubules. Moreover, there was not a corresponding increase in the number of mature sperm after 56 days of cryptorchidism.

CONCLUSION

The decline in germ cell apoptosis after 4 days of cryptorchidism can be attributed to be the result of an overall depletion of germ cells. It appears that after a prolonged cryptorchidism (56 days), there is a limited resumption of spermatogenesis presumably as a result of a decrease in the maturing germ cells undergoing programmed cell death.

摘要

目的

评估实验性隐睾对成年大鼠生殖细胞凋亡率和睾丸精子含量的长期影响。

方法

通过手术将40只成年雄性斯普拉格-道利大鼠的睾丸移入腹腔并关闭腹股沟内环，制造双侧隐睾模型。在隐睾术后6小时、2天、4天、7天、21天、28天和56天处死大鼠并取出睾丸。采用TUNEL法对生殖细胞凋亡进行定量分析，并用透射电子显微镜确认凋亡情况。

结果

隐睾术后4天凋亡率达到峰值，然后逐渐下降，在隐睾术后14天降至最低点。隐睾术后56天，生精上皮因凋亡过程而大量减少，睾丸内仅见少数成熟精子。此时，可见一些小管开始有初级精母细胞重新填充，生殖细胞凋亡水平开始略有上升。隐睾术后7天，睾丸精子计数（TSC）开始迅速下降。隐睾术后56天，大鼠睾丸中仅发现少数成熟精子。第4天时，曲细精管内多核巨细胞（MGC）数量最多。第7天时，35%的MGCs TUNEL染色呈阳性。然而，在所有后续时间点，MGCs凋亡染色均未呈阳性。凋亡增加的这种恢复与一些曲细精管中出现的初级精母细胞群体一致。此外，隐睾术后56天成熟精子数量并未相应增加。