Effect of alpha lipoic acid on in vitro development of bovine secondary preantral follicles

The present study aimed to evaluate the in vitro effect of alpha lipoic acid (ALA) addition to the culture medium on the development of the bovine secondary preantral follicles. Bovine secondary preantral follicles were collected and divided into two groups depending on their size (80–100 μm and 100–110 μm). They were cultured in vitro for 15 days (D) using different media including at three different doses of ALA. The genes expression levels of follicle-stimulating hormone beta-subunit (FSHR), insulin-like growth factor (IGF-1), Activin, luteinizing hormone/choriogonadotropin receptor, bone morphogenetic protein receptor type IA, transforming growth factor beta receptor 1, growth differentiation factor 9, BCL2-associated X protein (BAX), and C-Myc were studied using real-time polymerase chain reaction. The protein expression levels of FSHR, IGF-1, and BAX were measured using Western blot analysis. The results of the present work revealed that in vitro addition of ALA-induced significant increase in the growth and development of secondary preantral follicles throughout the culture period as compared to control. The FSHR, IGF-1, luteinizing hormone/choriogonadotropin receptor, bone morphogenetic protein receptor type IA, transforming growth factor beta receptor 1, growth differentiation factor 9, and Activin A genes were upregulated in ALA-treated follicles as compared to the control. On contrary, preapoptotic genes BAX and C-Myc were downregulated in treated follicles compared to control ones. The protein levels of FSHR and IGF-1 were highly expressed in treated follicles compared to control; however, BAX protein was downregulated in the treated follicles groups. The addition of ALA to the culture medium enhances secondary preantral follicles development and growth.