Determination of Precursor/Stem Cell for Testicular Interstitial Cells of Leydig.

为了确定睾丸间质组织Leydig细胞的增殖是来自前体细胞的成熟还是来自干细胞的分裂，研究了重复给予乙烷二甲磺酸盐（EDS）损害的Leydig细胞的再生，主要是使用形态计量学分析。第二次注射EDS（75 mg/kg BW，ip），间隔30天，诱导了与第一次EDS处理相似的Leydig细胞消失和随后再生的事件，再生过程加快。在第二次EDS处理的2天内，睾丸组织中的Leydig细胞数量和体积百分比显著减少，血清睾酮水平显著降低。第1次EDS后14 d开始出现，第2 d间质中溴脱氧尿苷标记细胞百分率显著增加，第14 d恢复到对照组水平。EDS的重复给药未能耗尽Leydig细胞。第4次注射后30天，间隔30天，大鼠睾丸间质细胞的数量和总体积以及血清睾酮水平与对照组几乎相同。这些结果有力地表明，存在间质细胞的干细胞，并且间质细胞的再生通过干细胞的分裂发生。EDS被认为是专门损害大鼠睾丸间质细胞。然而，本研究表明，重复使用EDS治疗也会损害曲细精管。

To determine whether the proliferation of Leydig cells of testicular interstitial tissue comes from maturation of precursor cells or from division of stem cells, the regeneration of Leydig cells impaired by repeated administration of ethane dimethanesulphonate (EDS) was studied, mainly using morphometric analysis. Second injection of EDS (75 mg/kg BW, ip) with an interval of 30 days induced a similar event of disappearance and subsequent regeneration of Leydig cells as in the first EDS treatment with a fastened course of regeneration. Leydig cells reduced remarkably in number and volume percentage in the testicular tissue, and serum testosterone levels noticeably decreased within 2 days of 2nd EDS treatment. They began to reappear on 7 days, and recovered to the same extent as that in the control rats on 30 days, while they had began to reappear after 14 days of 1st EDS.Percentage of cells labeled by bromodeoxyuridine in the interstitial tissue increased remarkably on 2 days and returned to the level of control on 14 days. Repeated administration of EDS failed to deplete Leydig cells. On 30 days after 4th injection with an interval of respective 30 days, rats had almost the same number and total volume of Leydig cells and serum testosterone levels as in the control. These results strongly suggest that a stem cell for Leydig cells exists, and that the regeneration of Leydig cells occurs by division of the stem cells. EDS has been considered to impair specifically rat Leydig cells. However, the present study revealed that repeated treatments with EDS impair seminiferous tubules as well.