Global changes in gene expression of buffalo cow corpus luteum during prostaglandin F2alpha- induced luteolysis

In monoovulatory species like bovines, a striking diversity in regulation of the corpus luteum (CL) function exists within species during different stages of the luteal phase. The function and life span of CL appears to be regulated by the interplay of both luteotrophic and luteolytic factors, whose roles and actions are varied from one species to another. Although, studies continue to expand our current understanding of the cellular and molecular actions of prostaglandin F 2alpha (PGF2α - a physiological luteolysin)-induced luteolysis, knowledge of the mechanism whereby, PGF2α mediates its luteolytic actions remains poorly understood. The mechanism of PGF2α-induced luteolysis is a complex process involving changes in expression of multiple genes encoding gene products that regulate steroidogenesis, stress related or apoptotic genes, factors involved in immune response and enzymes that stimulate PGF2α production. Thus, in the present study, efforts were made to identify the temporal changes in the global gene expression profile in the CL of buffalo cows in response to PGF2α treatment. The molecular signature of genome-wide transcriptional changes in the CL tissue subjected to PGF2α-induced luteolysis will expand our knowledge on basic mechanism/s that regulates the luteolytic process. The results obtained in this study provide insight into the mechanisms underlying the PGF2α- induced regression of CL.Keywords: CL, PGF2α, gene expression The objective of this study was to identify the PGF2α-induced temporal changes in transcriptome of bovine CL on day 11 of estrous cycle. In the experiments with buffalo cows, animals with history of normal estrous cyclicity were treated with Cloprostenol (an PGF2α analogue; 500 µg i.m.) on day 11 of the estrous cycle to induce luteolysis and CL tissues were collected at (control; n=4 amimals/time point), 3 (n=2 animals/time point), 6 and 18 (n=3 animals/time point) h post PGF2α administration to examine gene expression changes associated with immediate early and delayed changes in the CL, respectively. Following retrieval of CL from the ovary, flash frozen in liquid nitrogen and stored at -70 °C for the purpose of RNA isolation. The isolated RNA was labeled and hybridized to Affymetrix GeneChip Bovine Genome Arrays as per the manufacturer’s instructions.