小鼠生精细胞增殖与凋亡的年龄变化

AGE-SPECIFIC CHANGES OF PROLIFERATION AND APOPTOSIS IN THE SEMINIFEROUS EPITHELIUM OF LABORATORY MICE

为研究雄性小鼠睾丸在发生、发育过程生精细胞增殖与凋亡的年龄变化 ,本研究采用了免疫细胞化学、凋亡细胞原位检测、电镜及体视学图象分析等方法 ,对胚胎 15天到生后 10月各发育阶段生精细胞的超微结构、PCNA表达、凋亡情况进行了较深入地研究。结果 :(1)精原细胞PCNA反应在胚胎 15天为阳性 ,从胚胎 18天到生后 5天 ,降为弱阳性 ,而阳性的精原细胞在生后 7天重新出现 ,一直到生后 6月 ,仍可见部分精原细胞呈阳性反应 ;(2 )生后 3天 ,可见凋亡的精原细胞染色质浓缩 ,核膜出现明显的核周隙 ,核碎裂。凋亡细胞数从生后 1天到生后第 3周有增加的趋势 ,于生后第 3周出现峰值 ,之后降低。结论 :(1)PCNA阳性细胞面密度到生后第 2周出现峰值 ,而凋亡细胞数于生后 3周出现峰值。生精细胞凋亡的高峰要滞后其增殖峰 1周左右 ,而且与其所处生精周期的特定阶段有关 ;(2 )精原细胞在胚胎发育过程中向曲细精管周边迁移 ,其排列由无序到有序 ;(3)在生后各发育阶段中 ,精原细胞始终保持DNA复制的能力。

The ultrastructure, cell apoptosis and proliferation of the spermatogenic cells in mice during a series of development stages from 15th day of fetus to 10th month after birth were observed with a variety of techniques,such as immunocytochemistry (ICC), TUNEL method for detection of apoptotic cells in situ, electron microscopy and analysis of morphometry. The results demonstrated～that:(1)The PCNA positive spermatogonium were found at 15th day of fetus,then decreased from 18th day of fetus to the 5th day postnatal. At postnatal 7th day,the PCNA positive spermatogonium were found again,at the same time ,the spermatogonium were partly found positive till 6th month after birth; (2)At 3rd day after birth,the pyknotic chromatin in nucleus and progressive degeneration in plasmic structures were observed. The number of apoptotic cells reached its peaks on postnatal 21st day. Conclusion:(1)Surface densities of PCNA positive cells reached their peaks on 14th day after birth,but the number of apoptotic cells reached its peaks on 21st day postnatal,so the apoptotic peak was late the proliferating peak for a week,and related to the particular period in cycle of seminiferous epithelium; (2)The spermatogium were found move from center to the periphery of the seminiferous tubule and arrange disorder to order;(3)The spermatogonium remained replicating activity of DNA during the developing stage.