The occurrence of follicular cyst affects the embryonic developmental competences of buffalo oocytes under in vitro culture conditions

Abstract

Cystic ovarian disease (COD) is a major cause of infertility in dairy cows. This study aimed to investigate the impact of follicular cysts on the invitro blastocyst developmental competence of oocytes and the relative gene expression of blastocysts developed from the subordinate follicles of ipsilateral (ovary with cyst), contralateral (ovary opposite to cyst), and normal ovaries of buffaloes. A total of 2059 ovaries were collected from slaughterhouse and classified into three categories based on the presence of follicular cysts: a) ipsilateral, b) contralateral, and c) control (absence of cysts). Oocytes of grades A, B, and C were used for invitro maturation, invitro fertilization, and invitro culture. The cleavage rates of the ipsilateral (91.54 %) and contralateral (95.71 %) categories were higher (P < 0.01) than those of the control (76.82 %). Conversely, the blastocyst development rate was higher (P < 0.01) in control (32.67 %) than in ipsilateral (8.46 %) and contralateral (7.14 %) groups. The mRNA expression levels of maturation (BMP15), steroidogenesis (STAR, CYP19), antioxidant (SOD2, HSPB1) and anti-apoptotic (BCL2) genes were decreased in arrested embryos derived from both cystic (ipsilateral and contralateral) and control category follicles when compared to blastocysts derived from their respective category follicles. Conversely, BAX expression increased in arrested embryos. Expression of SOD2 and BAX was downregulated in blastocysts from both ipsilateral and contralateral categories compared to controls. The presence of one or more follicular cysts in either ovary affected the developmental competence of oocytes derived from subordinate follicles. Therefore, the buffaloes with cysts in either ovary should be avoided when aspirating follicles for IVF.