The Effect of Leptin on Luteal Angiogenic Factors in the Developing Porcine Corpus Luteum - Abstract
Defects or abnormalities in a CL are believed to account for approximately 65% of recurrent miscarriages. Abnormalities can be associated with incomplete angiogenesis, which leads to a decrease in progesterone production and potential loss of a conceptus. Luteal angiogenesis is regulated by factors, such as fibroblast growth factor-2 (FGF2), vascular endothelial growth factor (VEGF), and angiopoietin-1 (Ang1). Leptin can influence the expression of VEGF, Ang1, and FGF2 in a caprine CL. Therefore, it is hypothesized that leptin is involved in luteal angiogenesis during CL development in the porcine species. Twenty-four mature crossbred gilts were allocated to one of four groups relative to day of the estrous cycle in preparation for CL collection: day (D) 4, 5, 6, or 7 of the estrous cycle (n = 6 gilts/D). Luteal tissue was divided and either frozen in liquid nitrogen for RNA analysis or enzymatically dispersed for cell culture. Gene expression for VEGF, Ang1, FGF2, leptin (tissue only), and leptin receptor (ObRb, tissue only) in CL tissue and cell cultures was determined by qPCR. Dispersed cells were cultured with or without leptin (0, 10-12, 10-11, 10-10, 10-9, 10-8 M; n = 3 wells/dose/gilt) for 24 hours. The expression of FGF2 in luteal tissue significantly (P<0.0003) varied relative to D and Ang1 tended (P=0.1) to be highest in D 6 CL. Leptin increased (P<0.05) Ang1 in D4 cultured dispersed lutea and decreased (P<0.03) FGF2 in D7 cultured dispersed lutea. Collectively, leptin appears to be involved in the angiogenic process in the developing CL.