Assisted reproduction of endangered equids, such as Persian onagers (Equus hemionus onager), is vital for species conservation. Little is known about Persian onager reproductive functions, including functions of the uterine endometrium. Recently, successful cryopreservation of the domestic mare endometrium was reported, but there is no information on cryo-sensitivity or in vitro culture of endometrial tissues of any non-domestic equid. In the present study, endometrial explants from Persian onagers were cryopreserved and cultured in vitro for 5 days. There was no difference between endometrial explants when 10% and 20% dimethyl sulfoxide (DMSO) was used for cryopreservation. Cell viability and structural integrity were comparable to fresh tissue. Abundance of estrogen receptor-α (ESR1) and progesterone receptor (PGR) mRNA transcript in endometrial explants was less in most treatment groups compared to the fresh tissue control. There was variation in E-cadherin mRNA abundance in endometrial explants among treatment groups with some treatment groups having a lesser abundance compared to the control group. The abundance of Ki67 mRNA transcript of endometrial explants was not different among treatment groups compared to the control group. Results indicate that DMSO is a suitable cryoprotectant for the Persian onager endometrium, and in vitro culture in a liquid-gas interface can maintain Persian onager endometrial explants for as long as 5 days. Findings allow for a greater understanding of reproductive mechanisms in vitro for this endangered species and other domestic equids including donkeys.

中文翻译：

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波斯onager（马属hemionus onager）子宫内膜外植体冷冻保存和体外培养。

辅助繁殖濒临灭绝的马匹，例如波斯捕食者（Equus hemionus onager），对于物种保护至关重要。波斯对食人鱼的生殖功能，包括子宫内膜的功能知之甚少。近来，已有报道成功冷冻保存母马子宫内膜，但尚无关于冷冻敏感性或体外培养任何非家畜内膜组织的信息。在本研究中，冷冻保存了来自波斯捕食者的子宫内膜外植体，并在体外培养了5天。当使用10％和20％的二甲基亚砜（DMSO）进行冷冻保存时，子宫内膜外植体之间没有差异。细胞活力和结构完整性与新鲜组织相当。与新鲜组织对照相比，在大多数治疗组中，子宫内膜外植体中雌激素受体-α（ESR1）和孕激素受体（PGR）mRNA转录物的含量较少。在治疗组之间，子宫内膜外植体中的E-钙粘蛋白mRNA丰度存在差异，其中一些治疗组的丰度低于对照组。与对照组相比，治疗组子宫内膜外植体的Ki67 mRNA转录丰度无差异。结果表明，DMSO是适合波斯人onager子宫内膜的冷冻保护剂，并且在液-气界面中进行体外培养可以使波斯人onager子宫内膜外植体维持长达5天。