PTEN inhibitor and kit ligand increase in vitro activation and survival of primordial follicles in alpaca

Abstract

In mammals, activation of primordial follicles to primary follicle is a progressive and highly regulated process. There is evidence in mice that phosphatase and tensin homologue deleted on Chromosome 10 (PTEN) silencing is an important negative regulator of phosphatidylinositol 3-kinase (PI3K), which initiates activation of dormant follicles. The objective of the study was to evaluate the effect of the addition of PTEN inhibitor (bpV(HOpic)) (10 μM) and/or Kit Ligand (KL) (100 ng/mL) on the in vitro activation and survival of alpaca primordial follicles. Ovarian cortical fragments from 11 adult alpacas were cultured for 24 h in tissue culture medium (α-MEM⁺ ) supplemented with KL and bpV or the association of both. Subsequently, each sample was processed by classical histology and follicular counting and classification were performed. The results obtained show a reduction (p < 0.05) of primordial follicles in more than 50% in follicular tissue cultured in vitro in α-MEM⁺ or supplemented with bpV and/or KL versus the control (not cultured). Further, >25% increase in primary follicles in follicular tissue cultured in vitro in α-MEM⁺ or supplemented with KL and/or bpV versus control. However, the follicular survival rate showed a decrease of 20% in the cultured tissues, except for the α-MEM⁺ supplemented with KL and bpV. In conclusion, supplementation of bpV (HOpic) (10 μM) and KL (100 ng/mL) increased the activation in vitro of primordial follicles and survival after in vitro culture of alpaca ovarian tissue.

Keywords: PTEN inhibitor; follicular activation; follicular survival; kit ligand; primordial follicles.