Stimulated by retinoic acid 8 (Stra8), one of genes induced by
retinoic acid (RA), is required for the meiotic initiation of male spermatogenesis. The present study found that Stra8 inhibited apoptosis in male Stra8‑knockout mice, and in mice with
vitamin A deficiency and
vitamin A recovery in vivo. This phenotype was also verified in GC1 spermatogonia (spg) cells overexpressing Stra8. In addition, microarray analysis identified that there were nine differentially expressed genes (DEGs) in the Stra8‑overexpressed GC1 spg cells compared with the control groups; the expression of these nine genes was verified via
mRNA expression levels. The DEGs were as follows: Phosphatidylinositol‑dependent kinase 1 (PDK1), a key gene upstream of
protein kinase B (AKT); angiopoietin 2, a B‑cell
lymphoma 2 (Bcl‑2)‑inhibited gene; transcription factor 4,
glutathione S‑transferase P91 and ubiquitin‑specific protease 33, mitogen‑activated
protein kinase (MAPK)‑related genes; oxidative stress induced growth inhibitor 1, related to the P53 pathway; Bcl‑2, P53, ERK (MAPK1/3), c‑Jun N‑terminal
kinase (MAPK8/9), and P38 (
MAPK14), all of which are key genes involved in the AKT signaling pathway. Therefore, the present study further verified these genes and found that the
mRNA and
protein expression levels of PDK1, AKT, Bcl‑2 and ERK were increased. Although the
mRNA expression level of P53 was decreased, there was no significant difference in the
protein expression level in Stra8‑overexpressing GC1 spg cells compared with controls. In addition, Caspase 3, one of the executioner
caspases, was decreased in Stra8‑overexpressing GC1 spg cells compared with the control groups. Therefore, it was suggested that Stra8 may directly or indirectly inhibit
caspases through the AKT signaling pathway and ultimately exert an anti‑apoptotic effect in the male reproductive system.