Belling Kirstine C, Tanaka Masami, Dalgaard Marlene Danner, Nielsen John Erik, Nielsen Henrik Bjørn, Brunak Søren, Almstrup Kristian, Leffers Henrik
Reprod Biol Endocrinol. 2013 May 28;11:50. doi: 10.1186/1477-7827-11-50.
Radiotherapy is used routinely to treat testicular cancer. Testicular cells vary in radio-sensitivity and the aim of this study was to investigate cellular and molecular changes caused by low dose irradiation of mice testis and to identify transcripts from different cell types in the adult testis.
Transcriptome profiling was performed on total RNA from testes sampled at various time points (n = 17) after 1 Gy of irradiation. Transcripts displaying large overall expression changes during the time series, but small expression changes between neighbouring time points were selected for further analysis. These transcripts were separated into clusters and their cellular origin was determined. Immunohistochemistry and in silico quantification was further used to study cellular changes post-irradiation (pi).
We identified a subset of transcripts (n = 988) where changes in expression pi can be explained by changes in cellularity. We separated the transcripts into five unique clusters that we associated with spermatogonia, spermatocytes, early spermatids, late spermatids and somatic cells, respectively. Transcripts in the somatic cell cluster showed large changes in expression pi, mainly caused by changes in cellularity. Further investigations revealed that the low dose irradiation seemed to cause Leydig cell hyperplasia, which contributed to the detected expression changes in the somatic cell cluster.
The five clusters represent gene expression in distinct cell types of the adult testis. We observed large expression changes in the somatic cell profile, which mainly could be attributed to changes in cellularity, but hyperplasia of Leydig cells may also play a role. We speculate that the possible hyperplasia may be caused by lower testosterone production and inadequate inhibin signalling due to missing germ cells.
放射疗法常用于治疗睾丸癌。睾丸细胞的放射敏感性各不相同，本研究的目的是调查低剂量照射小鼠睾丸所引起的细胞和分子变化，并鉴定成年睾丸中不同细胞类型的转录本。
对1 Gy照射后不同时间点（n = 17）采集的睾丸总RNA进行转录组分析。选择在时间序列中显示出总体表达变化较大，但相邻时间点之间表达变化较小的转录本进行进一步分析。将这些转录本聚类并确定其细胞来源。进一步采用免疫组织化学和计算机定量分析来研究照射后（pi）的细胞变化。
我们鉴定出一组转录本（n = 988），其pi表达变化可由细胞数量变化来解释。我们将这些转录本分为五个独特的簇，分别与精原细胞、精母细胞、早期精子细胞、晚期精子细胞和体细胞相关。体细胞簇中的转录本显示出pi表达的巨大变化，主要是由细胞数量变化引起的。进一步研究表明，低剂量照射似乎导致了睾丸间质细胞增生，这促成了体细胞簇中检测到的表达变化。
这五个簇代表成年睾丸不同细胞类型中的基因表达。我们观察到体细胞谱中有较大的表达变化，这主要可归因于细胞数量的变化，但睾丸间质细胞增生也可能起作用。我们推测这种可能的增生可能是由于生殖细胞缺失导致睾酮分泌减少和抑制素信号不足所致。
