Abstract

Background. The domestic cat is a valuable model for the development of assistedreproductive technologies in endangered felids. However, domestic cat embryos culturedwithout the zona pellucida are not able to implant (1). The reason for this lack of implantationis still unknown. The objective of this study was to evaluate the expression of specificmiRNAs in domestic cat embryos cultured without the zona pellucida. Methods. Procedureswere approved by the ethics committee of the Universidad de Concepción (CEBB 616-2019). Experimental groups: 1) domestic cat embryos generated by IVF (ZI group). 2)domestic cat embryos generated by IVF and cultured without the zona pellucida (ZF group).In the ZF group, after IVF the zona pellucida was removed using pronase and embryos werecultured in microwells. Cleavage, morula, and blastocyst rates were estimated at days 2, 5and 7 of IVC. Blastocysts were subjected to RT-qPCR analysis using the standard curvemethod to evaluate miRNAs related to embryo development: miR-21, miR-24, mi25, miR-29, miR-96, miR-98, miR-196, miR-199, miR-130. Meanwhile, miR-103 and miR-191 wereused as internal control (2). The Wilcoxon non-parametric test was used for analysis (P <0.05). Results. No differences (% Mean ± SD) were observed in the cleavage: ZI = 201/455(44.2 ± 18.1), ZF = 240/585 (41.0 ±19.9); morula: ZI = 95/201 (47.3 ± 14.1), ZF = 122/240(50.8 ± 26.5); and blastocyst rates: ZI = 56/201 (27.9 ± 9.2), ZF = 86/240 (35.9 ± 19.7).However, the relative expression of miR-21, miR-25, miR-29 and miR-199 was higher in ZFblastocysts than in their ZI counterparts. Furthermore, the relative expression of miR-96 waslower in ZF blastocysts. Conclusion. Culture of domestic cat embryos without the zonapellucida did not affect in vitro development, but modified the expression of miR-21, miR-25,miR-29, miR-199 and miR-96 in blastocysts.