Impact of exogenous adrenocorticotropic hormone on gelatinase expression and steroidogenesis in the newly formed corpus luteum in sows

The development and sustained function of the corpus luteum (CL) after ovulation are important for embryo implantation and early pregnancy maintenance in mammals. Sows raised in commercial group-housing systems are vulnerable to stress and have elevated blood cortisol levels; therefore, it is pivotal to study the influence of increased cortisol levels in circulation on the reproduction of sows. In this study, we aimed to investigate whether stress induced by adrenocorticotropic hormone (ACTH) administration before estrus affected either the development or the functions of the newly formed CL in sows. The results showed that the gene expression levels of the P450 cholesterol side chain cleavage (P450scc) and 3β-hydroxysteroid dehydrogenase (3β-HSD) proteins of newly formed CLs were lower in the ACTH-treated sows than in the controls, whereas the expression and activity of matrix metalloproteinases (MMPs) were significantly downregulated (P < 0.05). Moreover, the vascular endothelial growth factor (VEGF)164 gene expression levels were significantly lower in the ACTH group than in the controls (P < 0.05). These findings indicate that ACTH-induced stress impairs vascularization, and affects the steroidogenesis of newly developed CLs in sows.