Zhang Jun, Deng Yanfei, Chen Weili, Zi Yonghong, Shi Deshun, Lu Fenghua
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, China.
Reprod Domest Anim. 2020 Nov;55(11):1501-1510. doi: 10.1111/rda.13799. Epub 2020 Oct 28.
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.
卵泡膜细胞（TCs）在卵泡生长和闭锁过程中起关键作用。TCs合成雄激素，作为颗粒细胞（GCs）将其芳香化生成卵母细胞成熟所需雌激素的底物。然而，以条件培养基形式存在的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，我们检测了TC条件培养基（TCCM）对水牛卵母细胞孤雌激活（PA）后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%比例添加到IVM培养基中的TCCM（2天&20%）对IVM率没有显著影响（43.06%对44.71%），但与对照组相比，显著（p<0.05）提高了PA后水牛卵母细胞的胚胎发育（卵母细胞裂解，80.93%对69.66%；囊胚形成，39.85%对32.84%）。然而，与对照组相比，单层TC显著（p<0.05）促进了PA后水牛卵母细胞的成熟效率（48.84%对44.53%）和胚胎发育（卵母细胞裂解，80.39%对69.32%；囊胚形成，35.38%对29.25%）。此外，TCs向条件培养基中分泌了一些睾酮，这显著（p<0.05）促进了水牛卵丘-卵母细胞复合体（COCs）中雌激素合成相关基因（CYP11A1、CYP19A1和17β-HSD）的表达水平。我们的研究表明，TCCM（2天&20%）对IVM效率没有显著影响，但主要通过刺激睾酮分泌和促进水牛COCs的雌二醇合成，提高了PA后卵母细胞的胚胎发育能力。
