The physical properties of the ovarian extracellular matrix (ECM) regulate the function of ovarian cells, specifically the ability of the ovary to maintain a quiescent primordial follicle pool while allowing a subset of follicles to grow and mature in the estrous cycle. Design of a long-term, cycling artificial ovary has been hindered by the limited information regarding the mechanical properties of the ovary. In particular, differences in the mechanical properties of the two ovarian compartments, the cortex and medulla, have never been quantified. Shear wave (SW) ultrasound elastography is an imaging modality that enables assessment of material properties, such as the mechanical properties, based on the velocity of SWs, and visualization of internal anatomy, when coupled with B-mode ultrasound. We used SW ultrasound elastography to assess whole, ex vivo bovine ovaries. We demonstrated, for the first time, a difference in mechanical properties, as inferred from SW velocity, between the cortex and medulla, as measured along the length (cortex: 2.57 ± 0.53 m/s, medulla: 2.87 ± 0.77 m/s, p < 0.0001) and width (cortex: 2.99 ± 0.81 m/s, medulla: 3.24 ± 0.97 m/s, p < 0.05) and that the spatial distribution and magnitude of SW velocity vary between these two anatomical planes. This work contributes to a larger body of literature assessing the mechanical properties of the ovary and related cells and specialized ECMs and will enable the rational design of biomimetic tissue engineered models and durable bioprostheses.

中文翻译：

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超声剪切波速度在离体牛卵巢的解剖区域中变化。

卵巢细胞外基质 (ECM) 的物理特性调节卵巢细胞的功能，特别是卵巢维持静止原始卵泡池同时允许一部分卵泡在发情周期中生长和成熟的能力。由于有关卵巢机械特性的信息有限，因此阻碍了长期循环人工卵巢的设计。特别是，两个卵巢隔室（皮质和髓质）的机械特性差异从未被量化过。剪切波 (SW) 超声弹性成像是一种成像模式，当与 B 型超声结合使用时，它可以根据 SW 的速度和内部解剖结构的可视化来评估材料特性，例如机械特性。我们使用 SW 超声弹性成像来评估整体，离体牛卵巢。我们首次展示了沿长度测量的皮质和髓质之间从 SW 速度推断出的机械特性差异（皮质：2.57 ± 0.53 m/s，髓质：2.87 ± 0.77 m/s，p  < 0.0001) 和宽度（皮质：2.99 ± 0.81 m/s，髓质：3.24 ± 0.97 m/s，p  < 0.05），并且 SW 速度的空间分布和幅度在这两个解剖平面之间变化。这项工作有助于大量文献评估卵巢和相关细胞以及专门的 ECM 的机械特性，并将使仿生组织工程模型和耐用生物假体的合理设计成为可能。