Theca cells (TCs) play a key role in follicular growth and atresia. TCs synthesize androgens that act as substrate for granulosa cells (GCs) aromatization to estrogens needed for oocyte maturation. However, the effects of TCs in the form of conditioned medium on in vitro maturation (IVM) and developmental competence of buffalo oocytes remain unclear. In the present study, we examined the impacts of TC‐conditioned medium (TCCM) on maturation efficiency and embryo development of buffalo oocytes after parthenogenic activation (PA). Our results showed that TCCM that was collected on day 2 and added to IVM medium at a 20% proportional level (2 days & 20%) exerted no significant effect on IVM rate (43.06% vs. 44.71%), but significantly (p < .05) enhanced embryo development (oocyte cleavage, 80.93% vs. 69.66%; blastocyst formation, 39.85% vs. 32.84%) of buffalo oocytes after PA compared with the control group. However, monolayer TC significantly (p < .05) promoted both maturation efficiency (48.84% vs. 44.53%) and embryo development (oocyte cleavage, 80.39% vs. 69.32%; blastocyst formation, 35.38% vs. 29.25%) of buffalo oocytes after PA compared to that in the control group. Furthermore, TCs secreted some testosterone into the conditioned medium, which significantly (p < .05) promoted the expression levels of oestrogen synthesis‐related genes (CYP11A1, CYP19A1 and 17β‐HSD) in buffalo cumulus–oocyte complexes (COCs). Our study indicated that TCCM (2 days & 20%) did not significantly affect IVM efficiency, but enhanced embryo developmental competence of oocytes after PA principally by stimulating the secretion of testosterone and facilitating estradiol synthesis of buffalo COCs.

中文翻译：

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添加到IVM中的theca细胞条件培养基可增强孤雌性激活后水牛（Bubalus bubalis）卵母细胞的胚胎发育能力。

卵泡膜细胞（TCs）在卵泡生长和闭锁中起关键作用。TC合成雄激素，作为颗粒细胞（GCs）芳香化的底物，成为卵母细胞成熟所需的雌激素。但是，条件培养基形式的TCs对水牛卵母细胞体外成熟（IVM）和发育能力的影响仍不清楚。在本研究中，我们检查了TC条件培养基（TCCM）对单性生殖激活（PA）后水牛卵母细胞成熟效率和胚胎发育的影响。我们的结果表明，在第2天收集并以20％比例（2天和20％）添加到IVM培养基中的TCCM对IVM发生率没有显着影响（43.06％对44.71％），但显着（p<0.05）与对照组相比，PA后水牛卵母细胞的胚胎发育增强（卵母细胞裂解率分别为80.93％和69.66％；胚泡形成率分别为39.85％和32.84％）。然而，单层TC显着（p  <.05）促进了水牛卵母细胞的成熟效率（48.84％vs. 44.53％）和胚胎发育（卵母细胞裂解，80.39％vs. 69.32％；胚泡形成，35.38％vs. 29.25％）。 PA后与对照组相比。此外，TCs在条件培养基中分泌了一些睾丸激素，这显着（p  <.05）促进了雌激素合成相关基因（CYP11A1，CYP19A1和17β-HSD）的表达水平）在水牛卵丘-卵母细胞复合体（COC）中。我们的研究表明，TCCM（2天和20％）不会显着影响IVM效率，但主要是通过刺激睾丸激素的分泌和促进水牛COC的雌二醇合成来增强PA后卵母细胞的胚胎发育能力。