Gene Expression Microarray Analysis Of Porcine Early Atretic Follicles

In follicular growth and development of female mammalian ovaries, only a limited number of follicles develop to ovulation, most of them (70%-99%) undergo degeneration and disappear at any stage of growth and development. This process is called "follicular atresia". Follicular atresia maybe happened in any stage of follicular growth and development, this is a normal physiological processes of reproduction. Follicular atresia is a multi-factors involved complex regulation process, many researches have been done about follicular atresia for a long time, but the exact molecular mechanism of follicular atresia regulation has not yet clarified so far, it still needs further exploration. It is of great significance to clarify the molecular mechanism of this physiological process for rich theory of reproduction, improving animal fertility, promoting development of embryo engineering and the Treatment of human reproductive disease.Mature Duroc×Landrace×Yorkshire sows were selected as experimental animals in this research. Three different criteria were used to classify each follicle into healthy (H), early atresia (EA), and progressive atresia (PA) three groups.In order to gain a comprehensive evaluation of the changes in gene transcriptional profiles during porcine follicular atresia, microarray analysis was performed in porcine ovarian follicles with different atretic status, and then quantitative real-time PCR was carried out to validate the differential expression of6genes (CYP11Al, IRG6, ALCAM, STAR, VEGFA, CYP19A3), representing3upregulated and3downregulated gene respectively. Microarray data showed that a total of12,601probe sets expressed in the healthy follicles,13,541in the early atretic follicles, and11,858in both healthy and early atretic follicles respectively.652transcripts were differentially expressed between healthy and early atretic follicles,211of which were up-regulated while441were down-regulated. Of the652DE transcripts,629matched annotated genes in the UniGene database, representing210and419significantly up-regulated and downregulated unique gene respectively. Further GO analysis revealed that these DE genes were involved in25biological processes categories. KEGG analysis indicated that38potential signaling pathways were related to early follicular atresia, including ECM-receptor interaction, focal adhesion, TGF-beta signaling pathway, MAPK signaling pathway, Wnt signaling pathway, mTOR signaling pathway, insulin signaling pathway and cell cycle and so on. Real-time RT-PCR confirmed the expression pattern of6selected genes. There was significant correlation between qRT-PCR results and microarray data. All the genes were of the similar expression trends in both methods, which indicated the reliability of the microarray analysis. These results provided a new comprehensive view of potential candidate molecules and regulatory pathways involved in early follicular atresia, which would merit further investigation for seeking new insights into the molecular mechanisms of porcine follicular atresia and contribute to a better understanding or approach for enhancing the efficiency of female reproduction in pigs.