Spermatogonial transplantation can contribute to developing a novel method of producing seedlings for both aquaculture and biotic conservation. This study's purpose was to investigate aging- and temperature-related changes in the numbers and stem cell functions of type-A spermatogonia (ASG) in the model fish medaka (Oryzias latipes). The ASG numbers in medaka of different ages were quantified via histological observation and enzymatic dissociation of vasa-Gfp medaka testes. The ASG numbers were higher in eight-month-old medaka (maturation) than in four-month-old medaka (the onset of maturation). However, ASG numbers decreased in 18-month-old medaka (senescence). Low water temperature appeared to slow down both testis development and aging processes. To study the effects of aging on ASG stem cell activity, testicular cell suspensions containing GFP-expressed ASG were prepared from vasa-Gfp medaka donors at 4 and 18 months of age and transplanted into recipient hybrid larvae of medaka (O. latipes x O. curvinotus), which provided young stem-cell-niches. The findings revealed no significant differences in ASG colonization rates isolated from medaka of different ages. Each group displayed similar rates of germ-line transmission. Furthermore, water temperature had no significant effects on each ASG's stem cell activity. Taken together, these results indicated that aging and temperature affect ASG numbers. However, ASG isolated from medaka with different ages were transplanted into gonads with a young niche microenvironment, and there was no evidence of donor aging on stem cell activity.

中文翻译：

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用于青鳉生殖细胞移植的精原干细胞的衰老和温度相关活性

精原细胞移植有助于开发一种新的水产养殖和生物保护育苗方法。本研究的目的是调查模型鱼鳉（Oryzias latipes）中 A 型精原细胞 (ASG) 的数量和干细胞功能的衰老和温度相关变化。通过组织学观察和 vasa-Gfp 青鳉睾丸的酶解对不同年龄青鳉中的 ASG 数量进行量化。八个月大的青鳉（成熟）的 ASG 数字高于四个月大的青鳉（成熟的开始）。然而，18 个月大的青鳉（衰老）的 ASG 数量下降。低水温似乎减缓了睾丸发育和老化过程。为了研究衰老对 ASG 干细胞活性的影响，含有 GFP 表达的 ASG 的睾丸细胞悬液从 vasa-Gfp 青鳉供体在 4 个月和 18 个月大时制备，并移植到青鳉（O. latipes x O. curvinotus）的受体杂交幼虫中，提供年轻的干细胞生态位。研究结果显示，从不同年龄的青鳉中分离出的 ASG 定植率没有显着差异。每组都显示出相似的种系传播率。此外，水温对每个 ASG 的干细胞活性没有显着影响。总之，这些结果表明老化和温度会影响 ASG 值。然而，从不同年龄的青鳉中分离出的 ASG 被移植到具有年轻生态位微环境的性腺中，并且没有证据表明供体老化对干细胞活性的影响。