Enhancing embryonic and full-term development during mouse cloning through post-activation treatment with JNJ-7706621

Somatic cell nuclear transfer (SCNT) is widely researched for animal cloning. However, SCNT embryos frequently exhibit reduced developmental potential compared to those generated through natural reproduction. This study aimed to improve SCNT mouse embryo development by assessing the effects of JNJ-7706621 (JNJ, a specific inhibitor of cyclin-dependent kinase 1 and aurora kinases) as a post-activation treatment, replacing cytochalasin B (CB). Parthenogenetically activated (PA) mouse embryos were cultured with CB (5 μg/mL) or JNJ (1, 10, or 50 μM) to determine the optimal concentration. The 10 μM JNJ and CB groups showed significantly higher developmental competency compared to the 1 and 50 μM JNJ groups. The 10 μM JNJ group also exhibited an increase in total cell number and a decrease in apoptotic cells compared to the CB group. SCNT mouse embryos treated with 10 μM JNJ showed improved development (CB: 39.9 % ± 6.4; JNJ: 61.4 % ± 4.4), with increases in total cell number (CB: 52.7 ± 3.6; JNJ: 70.7 ± 2.9), inner cell mass (CB: 10.4 ± 0.7; JNJ: 15.4 ± 1.1), and trophectoderm cells (CB: 42.3 ± 3.3; JNJ: 55.3 ± 2.5). JNJ treatment significantly reduced aberrant F-actin and tubulin compared to CB. It also reduced abnormal spindles in one-cell embryos and decreased blastomere fragmentation and DNA damage in two-cell SCNT embryos compared to CB. Importantly, JNJ treatment led to significantly higher implantation (CB: 50.8 % ± 3.7; JNJ: 68.3 % ± 4.3) and live birth rates (CB: 2.4 % ± 2.4; JNJ: 10.9 % ± 2.8) compared to CB. These results demonstrate that JNJ enhances cytoskeletal integrity and chromosome stability, ultimately improving both preimplantation development and full-term success in mouse SCNT embryos.