Imaging seminiferous tubules - a 9.4T MRI mouse model
Imaging seminiferous tubules - a 9.4T MRI mouse model
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生精小管成像 - 9.4T MRI 小鼠模型
DOI：
10.1101/155762
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Herigstad M
中科院分区：
文献类型：
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作者：
Herigstad M
生育问题影响了许多夫妇。关于男性生育能力的研究通常使用小鼠模型，因为它们的可用性和精子生成与人类相似。一个常见的目标是生精小管，这是精子产生的地方，通常使用活组织检查和组织分析进行研究。高场磁共振(MR)可能为研究不育模型的睾丸功能提供一种非侵入性的替代方法。在这里，我们评估了牺牲的小鼠的生精小管结构，以确定MR与组织学的比较是否有用。12只小鼠(11只35-57天龄，1只9个月龄)处死，在9.4T进行松弛增强序列快速获取磁共振成像。对所有小鼠的睾丸进行原位扫描，并对一组小鼠(n=4)进行切除。第二组小鼠(n=4)的睾丸被选作组织学分析。从MRI和组织学图像中手动测量生精小管直径。为自动分割生精小管和计算组织体积创建了定制的图像分析脚本。所有的体外和原位图像都显示了清晰的生精小管轮廓。总睾丸体积与生精小管体积的比率在体外和原位测量之间没有显著差异，在成熟和年轻小鼠中相似。成年动物的睾丸总体积和生精小管体积均较大。虽然组织切片比MRI图像倾向于更大的平均曲细精管直径，但我们发现MRI和组织学测量之间没有显著差异。高场磁共振可用于小鼠模型，以原位评估睾丸结构。所有的体积测量与组织学数据相比较都是有利的。原位扫描也清楚地显示了可识别的睾丸外组织，如附睾和前列腺组织。与精子成熟和精子发生相关的组织成像的可能性强调了MR如何在小鼠生育模型中成为一种有用的技术，然而，需要进一步的工作来优化组织分割并验证这种方法用于纵向研究。这种类型的测量可能会在未来扩展到人类生育研究。
Fertility problems affect many couples. Research into male fertility commonly uses mouse models due to their availability and similar spermatogenesis to humans. A common target is the seminiferous tubules, the site of spermatozoa production, typically studied using biopsies and histological analysis. High-field Magnetic Resonance (MR) may offer a non-invasive alternative to investigate testicular function in infertility models. Here, we assess seminiferous tubules structure in sacrificed mice to determine the usefulness of MR compared to histology. Twelve mice (11 aged 35-57 days, one >9 months) were sacrificed and MR imaged at 9.4T with a Rapid Acquisition with Relaxation Enhancement sequence. Testes were scanned in situ for all mice, and excised in a subset of mice (n=4). A second subset of mice (n=4) had their testes selected for histological analysis. Seminiferous tubule diameter was measured manually from MRI and histology images. Custom image analysis scripts were created for the automated segmentation of seminiferous tubules and calculation of tissue volumes. All ex vivo and in situ images of testes exhibited clear outlines of seminiferous tubules. Ratio of total testis volume to volume of seminiferous tubules did not differ significantly between ex vivo and in situ measurements, and were similar in mature and younger mice. Both total testis volume and seminiferous tubule volume were larger in the mature animal. While histological slices trended towards larger average seminiferous tubules diameter than MRI images, we found no significant differences between MRI and histological measurements. High-field MRI can be used in a mouse model to assess testicular structure in situ. All volumetric measurements compared favourably with histological data. In situ scans also clearly showed identifiable extra-testicular tissues, such as epididymis and prostate tissues. The potential to image tissues associated with sperm maturation as well as spermatogenesis emphasises how MR could be a useful technique in mouse models of fertility, however further work is required to optimize tissue segmentation and validate this method for use in longitudinal studies. This type of measurement could be extended to human fertility studies in the future.